Merge branch 'master' into add_proj_get_suggested_operation

24 files changed, 590 insertions, 157 deletions

diff --git a/configure.ac b/configure.ac
index fab8f0e1..fb185a1e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -360,7 +360,4 @@ fi
 
 AC_CONFIG_FILES([proj.pc])
 
-dnl Ignore WARNING:  'proj.pc.in' seems to ignore the --datarootdir setting
-AC_DEFUN([AC_DATAROOTDIR_CHECKED])
-
 AC_OUTPUT
diff --git a/data/sql/customizations.sql b/data/sql/customizations.sql
index 82328f3c..fd67b8a1 100644
--- a/data/sql/customizations.sql
+++ b/data/sql/customizations.sql
@@ -135,3 +135,35 @@ INSERT INTO "alias_name" VALUES('geodetic_datum','EPSG','6312','hermannskogel','
 INSERT INTO "alias_name" VALUES('geodetic_datum','EPSG','6299','ire65','PROJ');
 INSERT INTO "alias_name" VALUES('geodetic_datum','EPSG','6272','nzgd49','PROJ');
 INSERT INTO "alias_name" VALUES('geodetic_datum','EPSG','6277','OSGB36','PROJ');
+
+---- PROJ unit short names -----
+
+-- Linear units
+UPDATE unit_of_measure SET proj_short_name = 'mm'        WHERE auth_name = 'EPSG' AND code = '1025';
+UPDATE unit_of_measure SET proj_short_name = 'cm'        WHERE auth_name = 'EPSG' AND code = '1033';
+UPDATE unit_of_measure SET proj_short_name = 'm'         WHERE auth_name = 'EPSG' AND code = '9001';
+UPDATE unit_of_measure SET proj_short_name = 'ft'        WHERE auth_name = 'EPSG' AND code = '9002';
+UPDATE unit_of_measure SET proj_short_name = 'us-ft'     WHERE auth_name = 'EPSG' AND code = '9003';
+UPDATE unit_of_measure SET proj_short_name = 'fath'      WHERE auth_name = 'EPSG' AND code = '9014';
+UPDATE unit_of_measure SET proj_short_name = 'kmi'       WHERE auth_name = 'EPSG' AND code = '9030';
+UPDATE unit_of_measure SET proj_short_name = 'us-ch'     WHERE auth_name = 'EPSG' AND code = '9033';
+UPDATE unit_of_measure SET proj_short_name = 'us-mi'     WHERE auth_name = 'EPSG' AND code = '9035';
+UPDATE unit_of_measure SET proj_short_name = 'km'        WHERE auth_name = 'EPSG' AND code = '9036';
+UPDATE unit_of_measure SET proj_short_name = 'ind-ft'    WHERE auth_name = 'EPSG' AND code = '9081';
+UPDATE unit_of_measure SET proj_short_name = 'ind-yd'    WHERE auth_name = 'EPSG' AND code = '9085';
+UPDATE unit_of_measure SET proj_short_name = 'mi'        WHERE auth_name = 'EPSG' AND code = '9093';
+UPDATE unit_of_measure SET proj_short_name = 'yd'        WHERE auth_name = 'EPSG' AND code = '9096';
+UPDATE unit_of_measure SET proj_short_name = 'ch'        WHERE auth_name = 'EPSG' AND code = '9097';
+UPDATE unit_of_measure SET proj_short_name = 'link'      WHERE auth_name = 'EPSG' AND code = '9098';
+
+-- Angular units
+UPDATE unit_of_measure SET proj_short_name = 'rad'       WHERE auth_name = 'EPSG' AND code = '9101';
+UPDATE unit_of_measure SET proj_short_name = 'deg'       WHERE auth_name = 'EPSG' AND code = '9102';
+UPDATE unit_of_measure SET proj_short_name = 'grad'      WHERE auth_name = 'EPSG' AND code = '9105';
+
+-- PROJ specific units
+INSERT INTO "unit_of_measure" VALUES('PROJ','DM','decimeter','length',0.01,'dm',0);
+INSERT INTO "unit_of_measure" VALUES('PROJ','IN','inch','length',0.0254,'in',0);
+INSERT INTO "unit_of_measure" VALUES('PROJ','US_IN','US survey inch','length',0.025400050800101,'us-in',0);
+INSERT INTO "unit_of_measure" VALUES('PROJ','US_YD','US survey yard','length',0.914401828803658,'us-yd',0);
+INSERT INTO "unit_of_measure" VALUES('PROJ','IND_CH','Indian chain','length',20.11669506,'ind-ch',0);
diff --git a/data/sql/proj_db_table_defs.sql b/data/sql/proj_db_table_defs.sql
index 166929af..df20de31 100644
--- a/data/sql/proj_db_table_defs.sql
+++ b/data/sql/proj_db_table_defs.sql
@@ -14,6 +14,7 @@ CREATE TABLE unit_of_measure(
     name TEXT NOT NULL CHECK (length(name) >= 2),
     type TEXT NOT NULL CHECK (type IN ('length', 'angle', 'scale', 'time')),
     conv_factor FLOAT,
+    proj_short_name TEXT, -- PROJ string name, like 'm', 'ft'. Might be NULL
     deprecated BOOLEAN NOT NULL CHECK (deprecated IN (0, 1)),
     CONSTRAINT pk_unit_of_measure PRIMARY KEY (auth_name, code)
 );
diff --git a/data/sql/unit_of_measure.sql b/data/sql/unit_of_measure.sql
index a3011c94..d361c159 100644
--- a/data/sql/unit_of_measure.sql
+++ b/data/sql/unit_of_measure.sql
@@ -1,97 +1,97 @@
 --- This file has been generated by scripts/build_db.py. DO NOT EDIT !
 
-INSERT INTO "unit_of_measure" VALUES('EPSG','1024','bin','scale',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1025','millimetre','length',0.001,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1026','metre per second','length',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1027','millimetres per year','length',3.16887651727314875889e-11,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1028','parts per billion','scale',1.0e-09,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1029','year','time',31556925.445,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1030','parts per billion per year','scale',3.16887651727314834646e-17,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1031','milliarc-second','angle',4.84813681109535528357e-09,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1032','milliarc-seconds per year','angle',1.53631468932075975278e-16,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1033','centimetre','length',0.01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1034','centimetres per year','length',3.1688765172731483714e-10,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1035','radian per second','angle',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1036','unity per second','scale',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1040','second','time',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1041','parts per million per year','scale',3.1688765172731486173e-14,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1042','metres per year','length',3.16887651727314861947e-08,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','1043','arc-seconds per year','angle',1.53631468932075975646e-13,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9001','metre','length',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9002','foot','length',0.3048,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9003','US survey foot','length',3.04800609601219241184e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9005','Clarke''s foot','length',0.3047972654,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9014','fathom','length',1.8288,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9030','nautical mile','length',1852.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9031','German legal metre','length',1.0000135965,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9033','US survey chain','length',2.01168402336804703618e+01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9034','US survey link','length',2.0116840233680469141e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9035','US survey mile','length',1.60934721869443751532e+03,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9036','kilometre','length',1000.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9037','Clarke''s yard','length',0.9143917962,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9038','Clarke''s chain','length',20.1166195164,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9039','Clarke''s link','length',0.201166195164,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9040','British yard (Sears 1922)','length',9.14398414616028665236e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9041','British foot (Sears 1922)','length',3.04799471538676203241e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9042','British chain (Sears 1922)','length',2.01167651215526319683e+01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9043','British link (Sears 1922)','length',2.01167651215526294139e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9050','British yard (Benoit 1895 A)','length',0.9143992,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9051','British foot (Benoit 1895 A)','length',3.04799733333333322526e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9052','British chain (Benoit 1895 A)','length',20.1167824,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9053','British link (Benoit 1895 A)','length',0.201167824,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9060','British yard (Benoit 1895 B)','length',9.14399204289812361778e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9061','British foot (Benoit 1895 B)','length',3.04799734763270768755e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9062','British chain (Benoit 1895 B)','length',2.01167824943758724023e+01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9063','British link (Benoit 1895 B)','length',2.01167824943758705158e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9070','British foot (1865)','length',3.04800833333333354158e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9080','Indian foot','length',3.04799510248146943158e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9081','Indian foot (1937)','length',0.30479841,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9082','Indian foot (1962)','length',0.3047996,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9083','Indian foot (1975)','length',0.3047995,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9084','Indian yard','length',9.14398530744440773965e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9085','Indian yard (1937)','length',0.91439523,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9086','Indian yard (1962)','length',0.9143988,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9087','Indian yard (1975)','length',0.9143985,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9093','Statute mile','length',1609.344,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9094','Gold Coast foot','length',3.04799710181508809458e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9095','British foot (1936)','length',0.3048007491,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9096','yard','length',0.9144,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9097','chain','length',20.1168,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9098','link','length',0.201168,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9099','British yard (Sears 1922 truncated)','length',0.914398,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9101','radian','angle',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9102','degree','angle',1.74532925199432781271e-02,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9103','arc-minute','angle',2.90888208665721309346e-04,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9104','arc-second','angle',4.84813681109535476055e-06,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9105','grad','angle',1.57079632679489496205e-02,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9106','gon','angle',1.57079632679489496205e-02,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9107','degree minute second','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9108','degree minute second hemisphere','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9109','microradian','angle',1.0e-06,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9110','sexagesimal DMS','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9111','sexagesimal DM','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9112','centesimal minute','angle',1.57079632679489491868e-04,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9113','centesimal second','angle',1.57079632679489496951e-06,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9114','mil_6400','angle',9.81747704246809351283e-04,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9115','degree minute','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9116','degree hemisphere','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9117','hemisphere degree','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9118','degree minute hemisphere','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9119','hemisphere degree minute','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9120','hemisphere degree minute second','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9121','sexagesimal DMS.s','angle',NULL,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9122','degree (supplier to define representation)','angle',1.74532925199432781271e-02,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9201','unity','scale',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9202','parts per million','scale',1.0e-06,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9203','coefficient','scale',1.0,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9204','Bin width 330 US survey feet','length',1.00584201168402344707e+02,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9205','Bin width 165 US survey feet','length',5.02921005842011723538e+01,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9206','Bin width 82.5 US survey feet','length',2.51460502921005861769e+01,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9207','Bin width 37.5 metres','length',37.5,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9208','Bin width 25 metres','length',25.0,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9209','Bin width 12.5 metres','length',12.5,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9210','Bin width 6.25 metres','length',6.25,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9211','Bin width 3.125 metres','length',3.125,1);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9300','British foot (Sears 1922 truncated)','length',3.04799333333333366535e-01,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9301','British chain (Sears 1922 truncated)','length',20.116756,0);
-INSERT INTO "unit_of_measure" VALUES('EPSG','9302','British link (Sears 1922 truncated)','length',0.20116756,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1024','bin','scale',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1025','millimetre','length',0.001,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1026','metre per second','length',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1027','millimetres per year','length',3.16887651727314875889e-11,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1028','parts per billion','scale',1.0e-09,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1029','year','time',31556925.445,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1030','parts per billion per year','scale',3.16887651727314834646e-17,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1031','milliarc-second','angle',4.84813681109535528357e-09,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1032','milliarc-seconds per year','angle',1.53631468932075975278e-16,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1033','centimetre','length',0.01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1034','centimetres per year','length',3.1688765172731483714e-10,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1035','radian per second','angle',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1036','unity per second','scale',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1040','second','time',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1041','parts per million per year','scale',3.1688765172731486173e-14,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1042','metres per year','length',3.16887651727314861947e-08,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','1043','arc-seconds per year','angle',1.53631468932075975646e-13,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9001','metre','length',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9002','foot','length',0.3048,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9003','US survey foot','length',3.04800609601219241184e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9005','Clarke''s foot','length',0.3047972654,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9014','fathom','length',1.8288,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9030','nautical mile','length',1852.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9031','German legal metre','length',1.0000135965,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9033','US survey chain','length',2.01168402336804703618e+01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9034','US survey link','length',2.0116840233680469141e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9035','US survey mile','length',1.60934721869443751532e+03,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9036','kilometre','length',1000.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9037','Clarke''s yard','length',0.9143917962,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9038','Clarke''s chain','length',20.1166195164,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9039','Clarke''s link','length',0.201166195164,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9040','British yard (Sears 1922)','length',9.14398414616028665236e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9041','British foot (Sears 1922)','length',3.04799471538676203241e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9042','British chain (Sears 1922)','length',2.01167651215526319683e+01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9043','British link (Sears 1922)','length',2.01167651215526294139e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9050','British yard (Benoit 1895 A)','length',0.9143992,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9051','British foot (Benoit 1895 A)','length',3.04799733333333322526e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9052','British chain (Benoit 1895 A)','length',20.1167824,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9053','British link (Benoit 1895 A)','length',0.201167824,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9060','British yard (Benoit 1895 B)','length',9.14399204289812361778e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9061','British foot (Benoit 1895 B)','length',3.04799734763270768755e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9062','British chain (Benoit 1895 B)','length',2.01167824943758724023e+01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9063','British link (Benoit 1895 B)','length',2.01167824943758705158e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9070','British foot (1865)','length',3.04800833333333354158e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9080','Indian foot','length',3.04799510248146943158e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9081','Indian foot (1937)','length',0.30479841,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9082','Indian foot (1962)','length',0.3047996,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9083','Indian foot (1975)','length',0.3047995,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9084','Indian yard','length',9.14398530744440773965e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9085','Indian yard (1937)','length',0.91439523,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9086','Indian yard (1962)','length',0.9143988,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9087','Indian yard (1975)','length',0.9143985,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9093','Statute mile','length',1609.344,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9094','Gold Coast foot','length',3.04799710181508809458e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9095','British foot (1936)','length',0.3048007491,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9096','yard','length',0.9144,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9097','chain','length',20.1168,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9098','link','length',0.201168,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9099','British yard (Sears 1922 truncated)','length',0.914398,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9101','radian','angle',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9102','degree','angle',1.74532925199432781271e-02,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9103','arc-minute','angle',2.90888208665721309346e-04,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9104','arc-second','angle',4.84813681109535476055e-06,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9105','grad','angle',1.57079632679489496205e-02,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9106','gon','angle',1.57079632679489496205e-02,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9107','degree minute second','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9108','degree minute second hemisphere','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9109','microradian','angle',1.0e-06,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9110','sexagesimal DMS','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9111','sexagesimal DM','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9112','centesimal minute','angle',1.57079632679489491868e-04,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9113','centesimal second','angle',1.57079632679489496951e-06,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9114','mil_6400','angle',9.81747704246809351283e-04,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9115','degree minute','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9116','degree hemisphere','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9117','hemisphere degree','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9118','degree minute hemisphere','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9119','hemisphere degree minute','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9120','hemisphere degree minute second','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9121','sexagesimal DMS.s','angle',NULL,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9122','degree (supplier to define representation)','angle',1.74532925199432781271e-02,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9201','unity','scale',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9202','parts per million','scale',1.0e-06,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9203','coefficient','scale',1.0,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9204','Bin width 330 US survey feet','length',1.00584201168402344707e+02,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9205','Bin width 165 US survey feet','length',5.02921005842011723538e+01,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9206','Bin width 82.5 US survey feet','length',2.51460502921005861769e+01,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9207','Bin width 37.5 metres','length',37.5,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9208','Bin width 25 metres','length',25.0,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9209','Bin width 12.5 metres','length',12.5,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9210','Bin width 6.25 metres','length',6.25,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9211','Bin width 3.125 metres','length',3.125,NULL,1);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9300','British foot (Sears 1922 truncated)','length',3.04799333333333366535e-01,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9301','British chain (Sears 1922 truncated)','length',20.116756,NULL,0);
+INSERT INTO "unit_of_measure" VALUES('EPSG','9302','British link (Sears 1922 truncated)','length',0.20116756,NULL,0);
diff --git a/docs/source/development/reference/functions.rst b/docs/source/development/reference/functions.rst
index 983e8a50..2d68ff68 100644
--- a/docs/source/development/reference/functions.rst
+++ b/docs/source/development/reference/functions.rst
@@ -521,6 +521,9 @@ Lists
     entry of the returned array is a NULL-entry. The array is statically
     allocated and does not need to be freed after use.
 
+    Note: starting with PROJ 7.1, this function is deprecated by
+    :cpp:func:`proj_get_units_from_database`
+
     :returns: :c:type:`PJ_UNITS*`
 
 .. c:function:: const PJ_PRIME_MERIDIANS* proj_list_prime_meridians(void)
diff --git a/include/proj/io.hpp b/include/proj/io.hpp
index 3dcf7928..f07f78b8 100644
--- a/include/proj/io.hpp
+++ b/include/proj/io.hpp
@@ -1013,6 +1013,8 @@ class PROJ_GCC_DLL AuthorityFactory {
 
     PROJ_DLL std::string getDescriptionText(const std::string &code) const;
 
+    // non-standard
+
     /** CRS information */
     struct CRSInfo {
         /** Authority name */
@@ -1049,7 +1051,33 @@ class PROJ_GCC_DLL AuthorityFactory {
 
     PROJ_DLL std::list<CRSInfo> getCRSInfoList() const;
 
-    // non-standard
+    /** Unit information */
+    struct UnitInfo {
+        /** Authority name */
+        std::string authName;
+        /** Code */
+        std::string code;
+        /** Name */
+        std::string name;
+        /** Category: one of "linear", "linear_per_time", "angular",
+         * "angular_per_time", "scale", "scale_per_time" or "time" */
+        std::string category;
+        /** Conversion factor to the SI unit.
+         * It might be 0 in some cases to indicate no known conversion factor.
+         */
+        double convFactor;
+        /** PROJ short name (may be empty) */
+        std::string projShortName;
+        /** Whether the object is deprecated */
+        bool deprecated;
+
+        //! @cond Doxygen_Suppress
+        UnitInfo();
+        //! @endcond
+    };
+
+    PROJ_DLL std::list<UnitInfo> getUnitList() const;
+
     PROJ_DLL static AuthorityFactoryNNPtr
     create(const DatabaseContextNNPtr &context,
            const std::string &authorityName);
diff --git a/proj.pc.in b/proj.pc.in
index f66da74d..7e462138 100644
--- a/proj.pc.in
+++ b/proj.pc.in
@@ -2,6 +2,7 @@ prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
 includedir=@includedir@
+datarootdir=@datarootdir@
 datadir=@datadir@/@PACKAGE@
 
 Name: PROJ
diff --git a/scripts/build_db.py b/scripts/build_db.py
index 6eed3867..5897a2d8 100755
--- a/scripts/build_db.py
+++ b/scripts/build_db.py
@@ -68,7 +68,7 @@ def ingest_epsg():
 
 def fill_unit_of_measure(proj_db_cursor):
     proj_db_cursor.execute(
-        "INSERT INTO unit_of_measure SELECT ?, uom_code, unit_of_meas_name, unit_of_meas_type, factor_b / factor_c, deprecated FROM epsg.epsg_unitofmeasure", (EPSG_AUTHORITY,))
+        "INSERT INTO unit_of_measure SELECT ?, uom_code, unit_of_meas_name, unit_of_meas_type, factor_b / factor_c, NULL, deprecated FROM epsg.epsg_unitofmeasure", (EPSG_AUTHORITY,))
 
 
 def fill_ellipsoid(proj_db_cursor):
diff --git a/src/apps/cs2cs.cpp b/src/apps/cs2cs.cpp
index 6c85d4aa..affd2bec 100644
--- a/src/apps/cs2cs.cpp
+++ b/src/apps/cs2cs.cpp
@@ -425,11 +425,18 @@ int main(int argc, char **argv) {
                             (void)printf("%9s %-16s %-16s %s\n", le->id,
                                          le->major, le->ell, le->name);
                     } else if (arg[1] == 'u') { /* list units */
-                        const struct PJ_UNITS *lu;
-
-                        for (lu = proj_list_units(); lu->id; ++lu)
-                            (void)printf("%12s %-20s %s\n", lu->id,
-                                         lu->to_meter, lu->name);
+                        auto units = proj_get_units_from_database(nullptr, nullptr, "linear", false, nullptr);
+                        for( int i = 0; units && units[i]; i++ )
+                        {
+                            if( units[i]->proj_short_name )
+                            {
+                                (void)printf("%12s %-20.15g %s\n",
+                                                units[i]->proj_short_name,
+                                                units[i]->conv_factor,
+                                                units[i]->name);
+                            }
+                        }
+                        proj_unit_list_destroy(units);
                     } else if (arg[1] == 'm') { /* list prime meridians */
                         const struct PJ_PRIME_MERIDIANS *lpm;
 
diff --git a/src/apps/geod.cpp b/src/apps/geod.cpp
index b46188d3..919430ca 100644
--- a/src/apps/geod.cpp
+++ b/src/apps/geod.cpp
@@ -185,11 +185,18 @@ noargument:		   emess(1,"missing argument for -%c",*arg);
                                         (void)printf("%9s %-16s %-16s %s\n",
                                                      le->id, le->major, le->ell, le->name);
 				} else if (arg[1] == 'u') { /* list of units */
-                                    const struct PJ_UNITS *lu;
-                                    
-                                    for (lu = proj_list_units();lu->id ; ++lu)
-                                        (void)printf("%12s %-20s %s\n",
-                                                     lu->id, lu->to_meter, lu->name);
+                                    auto units = proj_get_units_from_database(nullptr, nullptr, "linear", false, nullptr);
+                                    for( int i = 0; units && units[i]; i++ )
+                                    {
+                                        if( units[i]->proj_short_name )
+                                        {
+                                            (void)printf("%12s %-20.15g %s\n",
+                                                         units[i]->proj_short_name,
+                                                         units[i]->conv_factor,
+                                                         units[i]->name);
+                                        }
+                                    }
+                                    proj_unit_list_destroy(units);
 				} else
                                     emess(1,"invalid list option: l%c",arg[1]);
                                 exit( 0 );
diff --git a/src/apps/geod_set.cpp b/src/apps/geod_set.cpp
index ed7edeb9..603f0d95 100644
--- a/src/apps/geod_set.cpp
+++ b/src/apps/geod_set.cpp
@@ -14,7 +14,6 @@ geod_set(int argc, char **argv) {
 	paralist *start = nullptr, *curr;
 	double es;
 	char *name;
-	int i;
 
     /* put arguments into internal linked list */
 	if (argc <= 0)
@@ -22,7 +21,7 @@ geod_set(int argc, char **argv) {
 	start = curr = pj_mkparam(argv[0]);
 	if (!curr)
 		emess(1, "memory allocation failed");
-	for (i = 1; curr != nullptr && i < argc; ++i) {
+	for (int i = 1; curr != nullptr && i < argc; ++i) {
 		curr->next = pj_mkparam(argv[i]);
 		if (!curr->next)
 			emess(1, "memory allocation failed");
@@ -32,13 +31,20 @@ geod_set(int argc, char **argv) {
 	if (pj_ell_set(pj_get_default_ctx(),start, &geod_a, &es)) emess(1,"ellipse setup failure");
 	/* set units */
 	if ((name = pj_param(nullptr,start, "sunits").s) != nullptr) {
-		const char *s;
-                const struct PJ_UNITS *unit_list = proj_list_units();
-		for (i = 0; (s = unit_list[i].id) && strcmp(name, s) ; ++i) ;
-		if (!s)
-			emess(1,"%s unknown unit conversion id", name);
-		to_meter = unit_list[i].factor;
-		fr_meter = 1 / to_meter;
+            bool unit_found = false;
+            auto units = proj_get_units_from_database(nullptr, nullptr, "linear", false, nullptr);
+            for( int i = 0; units && units[i]; i++ )
+            {
+                if( units[i]->proj_short_name &&
+                    strcmp(units[i]->proj_short_name, name) == 0 ) {
+                    unit_found = true;
+                    to_meter = units[i]->conv_factor;
+                    fr_meter = 1 / to_meter;
+                }
+            }
+            proj_unit_list_destroy(units);
+            if( !unit_found )
+                emess(1,"%s unknown unit conversion id", name);
 	} else
 		to_meter = fr_meter = 1;
 	geod_f = es/(1 + sqrt(1 - es));
diff --git a/src/apps/proj.cpp b/src/apps/proj.cpp
index 852cea04..0bf98b3a 100644
--- a/src/apps/proj.cpp
+++ b/src/apps/proj.cpp
@@ -380,11 +380,18 @@ int main(int argc, char **argv) {
                         (void)printf("%9s %-16s %-16s %s\n",
                                      le->id, le->major, le->ell, le->name);
                 } else if (arg[1] == 'u') { /* list units */
-                    const struct PJ_UNITS *lu;
-
-                    for (lu = proj_list_units(); lu->id ; ++lu)
-                        (void)printf("%12s %-20s %s\n",
-                                     lu->id, lu->to_meter, lu->name);
+                    auto units = proj_get_units_from_database(nullptr, nullptr, "linear", false, nullptr);
+                    for( int i = 0; units && units[i]; i++ )
+                    {
+                        if( units[i]->proj_short_name )
+                        {
+                            (void)printf("%12s %-20.15g %s\n",
+                                            units[i]->proj_short_name,
+                                            units[i]->conv_factor,
+                                            units[i]->name);
+                        }
+                    }
+                    proj_unit_list_destroy(units);
                 } else
                     emess(1,"invalid list option: l%c",arg[1]);
                 exit(0);
diff --git a/src/conversions/unitconvert.cpp b/src/conversions/unitconvert.cpp
index f8439aee..6ce55b02 100644
--- a/src/conversions/unitconvert.cpp
+++ b/src/conversions/unitconvert.cpp
@@ -393,9 +393,7 @@ static double get_unit_conversion_factor(const char* name,
 /***********************************************************************/
     int i;
     const char* s;
-    const PJ_UNITS *units;
-
-    units = proj_list_units();
+    const PJ_UNITS *units = pj_list_linear_units();
 
     /* Try first with linear units */
     for (i = 0; (s = units[i].id) ; ++i) {
diff --git a/src/grids.cpp b/src/grids.cpp
index b9da072c..c5fc6c74 100644
--- a/src/grids.cpp
+++ b/src/grids.cpp
@@ -309,8 +309,11 @@ constexpr uint16 TIFFTAG_GEOTRANSMATRIX = 34264;
 constexpr uint16 TIFFTAG_GEOKEYDIRECTORY = 34735;
 constexpr uint16 TIFFTAG_GEODOUBLEPARAMS = 34736;
 constexpr uint16 TIFFTAG_GEOASCIIPARAMS = 34737;
+#ifndef TIFFTAG_GDAL_METADATA
+// Starting with libtiff > 4.1.0, those symbolic names are #define in tiff.h
 constexpr uint16 TIFFTAG_GDAL_METADATA = 42112;
 constexpr uint16 TIFFTAG_GDAL_NODATA = 42113;
+#endif
 
 // ---------------------------------------------------------------------------
 
@@ -1373,7 +1376,8 @@ VerticalShiftGridSet::open(PJ_CONTEXT *ctx, const std::string &filename) {
 
     if (IsTIFF(header_size, header)) {
 #ifdef TIFF_ENABLED
-        auto set = GTiffVGridShiftSet::open(ctx, std::move(fp), actualName);
+        auto set = std::unique_ptr<VerticalShiftGridSet>(
+            GTiffVGridShiftSet::open(ctx, std::move(fp), actualName));
         if (!set)
             pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
         return set;
@@ -2351,7 +2355,8 @@ HorizontalShiftGridSet::open(PJ_CONTEXT *ctx, const std::string &filename) {
     } else if (IsTIFF(header_size,
                       reinterpret_cast<const unsigned char *>(header))) {
 #ifdef TIFF_ENABLED
-        auto set = GTiffHGridShiftSet::open(ctx, std::move(fp), actualName);
+        auto set = std::unique_ptr<HorizontalShiftGridSet>(
+            GTiffHGridShiftSet::open(ctx, std::move(fp), actualName));
         if (!set)
             pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
         return set;
@@ -2686,8 +2691,8 @@ GenericShiftGridSet::open(PJ_CONTEXT *ctx, const std::string &filename) {
 
     if (IsTIFF(header_size, header)) {
 #ifdef TIFF_ENABLED
-        auto set =
-            GTiffGenericGridShiftSet::open(ctx, std::move(fp), actualName);
+        auto set = std::unique_ptr<GenericShiftGridSet>(
+            GTiffGenericGridShiftSet::open(ctx, std::move(fp), actualName));
         if (!set)
             pj_ctx_set_errno(ctx, PJD_ERR_FAILED_TO_LOAD_GRID);
         return set;
diff --git a/src/init.cpp b/src/init.cpp
index a25d1ccd..101fc8ad 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -738,7 +738,7 @@ pj_init_ctx_with_allow_init_epsg(projCtx ctx, int argc, char **argv, int allow_i
         return pj_default_destructor (PIN, PJD_ERR_K_LESS_THAN_ZERO);
 
     /* Set units */
-    units = proj_list_units();
+    units = pj_list_linear_units();
     s = nullptr;
     if ((name = pj_param(ctx, start, "sunits").s) != nullptr) {
         for (i = 0; (s = units[i].id) && strcmp(name, s) ; ++i) ;
diff --git a/src/iso19111/c_api.cpp b/src/iso19111/c_api.cpp
index d9def9d6..d7fb35f3 100644
--- a/src/iso19111/c_api.cpp
+++ b/src/iso19111/c_api.cpp
@@ -667,7 +667,8 @@ PJ *proj_create_from_database(PJ_CONTEXT *ctx, const char *auth_name,
 // ---------------------------------------------------------------------------
 
 //! @cond Doxygen_Suppress
-static const char *get_unit_category(UnitOfMeasure::Type type) {
+static const char *get_unit_category(const std::string &unit_name,
+                                     UnitOfMeasure::Type type) {
     const char *ret = nullptr;
     switch (type) {
     case UnitOfMeasure::Type::UNKNOWN:
@@ -677,19 +678,26 @@ static const char *get_unit_category(UnitOfMeasure::Type type) {
         ret = "none";
         break;
     case UnitOfMeasure::Type::ANGULAR:
-        ret = "angular";
+        ret = unit_name.find(" per ") != std::string::npos ? "angular_per_time"
+                                                           : "angular";
         break;
     case UnitOfMeasure::Type::LINEAR:
-        ret = "linear";
+        ret = unit_name.find(" per ") != std::string::npos ? "linear_per_time"
+                                                           : "linear";
         break;
     case UnitOfMeasure::Type::SCALE:
-        ret = "scale";
+        ret = unit_name.find(" per year") != std::string::npos ||
+                      unit_name.find(" per second") != std::string::npos
+                  ? "scale_per_time"
+                  : "scale";
         break;
     case UnitOfMeasure::Type::TIME:
         ret = "time";
         break;
     case UnitOfMeasure::Type::PARAMETRIC:
-        ret = "parametric";
+        ret = unit_name.find(" per ") != std::string::npos
+                  ? "parametric_per_time"
+                  : "parametric";
         break;
     }
     return ret;
@@ -709,8 +717,9 @@ static const char *get_unit_category(UnitOfMeasure::Type type) {
  * @param out_conv_factor Pointer to a value to store the conversion
  * factor of the prime meridian longitude unit to radian. or NULL
  * @param out_category Pointer to a string value to store the parameter name. or
- * NULL. This value might be "unknown", "none", "linear", "angular", "scale",
- * "time" or "parametric";
+ * NULL. This value might be "unknown", "none", "linear", "linear_per_time",
+ * "angular", "angular_per_time", "scale", "scale_per_time", "time",
+ * "parametric" or "parametric_per_time"
  * @return TRUE in case of success
  */
 int proj_uom_get_info_from_database(PJ_CONTEXT *ctx, const char *auth_name,
@@ -731,7 +740,7 @@ int proj_uom_get_info_from_database(PJ_CONTEXT *ctx, const char *auth_name,
             *out_conv_factor = obj->conversionToSI();
         }
         if (out_category) {
-            *out_category = get_unit_category(obj->type());
+            *out_category = get_unit_category(obj->name(), obj->type());
         }
         ctx->cpp_context->autoCloseDbIfNeeded();
         return true;
@@ -2590,6 +2599,100 @@ void proj_crs_info_list_destroy(PROJ_CRS_INFO **list) {
 
 // ---------------------------------------------------------------------------
 
+/** \brief Enumerate units from the database, taking into account various
+ * criteria.
+ *
+ * The returned object is an array of PROJ_UNIT_INFO* pointers, whose last
+ * entry is NULL. This array should be freed with proj_unit_list_destroy()
+ *
+ * @param ctx PROJ context, or NULL for default context
+ * @param auth_name Authority name, used to restrict the search.
+ * Or NULL for all authorities.
+ * @param category Filter by category, if this parameter is not NULL. Category
+ * is one of "linear", "linear_per_time", "angular", "angular_per_time",
+ * "scale", "scale_per_time" or "time"
+ * @param allow_deprecated whether we should return deprecated objects as well.
+ * @param out_result_count Output parameter pointing to an integer to receive
+ * the size of the result list. Might be NULL
+ * @return an array of PROJ_UNIT_INFO* pointers to be freed with
+ * proj_unit_list_destroy(), or NULL in case of error.
+ *
+ * @since 7.1
+ */
+PROJ_UNIT_INFO **proj_get_units_from_database(PJ_CONTEXT *ctx,
+                                              const char *auth_name,
+                                              const char *category,
+                                              int allow_deprecated,
+                                              int *out_result_count) {
+    SANITIZE_CTX(ctx);
+    PROJ_UNIT_INFO **ret = nullptr;
+    int i = 0;
+    try {
+        auto factory = AuthorityFactory::create(getDBcontext(ctx),
+                                                auth_name ? auth_name : "");
+        auto list = factory->getUnitList();
+        ret = new PROJ_UNIT_INFO *[list.size() + 1];
+        for (const auto &info : list) {
+            if (category && info.category != category) {
+                continue;
+            }
+            if (!allow_deprecated && info.deprecated) {
+                continue;
+            }
+            ret[i] = new PROJ_UNIT_INFO;
+            ret[i]->auth_name = pj_strdup(info.authName.c_str());
+            ret[i]->code = pj_strdup(info.code.c_str());
+            ret[i]->name = pj_strdup(info.name.c_str());
+            ret[i]->category = pj_strdup(info.category.c_str());
+            ret[i]->conv_factor = info.convFactor;
+            ret[i]->proj_short_name =
+                info.projShortName.empty()
+                    ? nullptr
+                    : pj_strdup(info.projShortName.c_str());
+            ret[i]->deprecated = info.deprecated;
+            i++;
+        }
+        ret[i] = nullptr;
+        if (out_result_count)
+            *out_result_count = i;
+        ctx->cpp_context->autoCloseDbIfNeeded();
+        return ret;
+    } catch (const std::exception &e) {
+        proj_log_error(ctx, __FUNCTION__, e.what());
+        if (ret) {
+            ret[i + 1] = nullptr;
+            proj_unit_list_destroy(ret);
+        }
+        if (out_result_count)
+            *out_result_count = 0;
+    }
+    ctx->cpp_context->autoCloseDbIfNeeded();
+    return nullptr;
+}
+
+// ---------------------------------------------------------------------------
+
+/** \brief Destroy the result returned by
+ * proj_get_units_from_database().
+ *
+ * @since 7.1
+ */
+void proj_unit_list_destroy(PROJ_UNIT_INFO **list) {
+    if (list) {
+        for (int i = 0; list[i] != nullptr; i++) {
+            pj_dalloc(list[i]->auth_name);
+            pj_dalloc(list[i]->code);
+            pj_dalloc(list[i]->name);
+            pj_dalloc(list[i]->category);
+            pj_dalloc(list[i]->proj_short_name);
+            delete list[i];
+        }
+        delete[] list;
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 /** \brief Return the Conversion of a DerivedCRS (such as a ProjectedCRS),
  * or the Transformation from the baseCRS to the hubCRS of a BoundCRS
  *
@@ -6754,8 +6857,9 @@ int proj_coordoperation_get_param_index(PJ_CONTEXT *ctx,
  * unit code. or NULL
  * @param out_unit_category Pointer to a string value to store the parameter
  * name. or
- * NULL. This value might be "unknown", "none", "linear", "angular", "scale",
- * "time" or "parametric";
+ * NULL. This value might be "unknown", "none", "linear", "linear_per_time",
+ * "angular", "angular_per_time", "scale", "scale_per_time", "time",
+ * "parametric" or "parametric_per_time"
  * @return TRUE in case of success.
  */
 
@@ -6857,7 +6961,8 @@ int proj_coordoperation_get_param(
                 *out_unit_code = unit.code().c_str();
             }
             if (out_unit_category) {
-                *out_unit_category = get_unit_category(unit.type());
+                *out_unit_category =
+                    get_unit_category(unit.name(), unit.type());
             }
         }
     }
diff --git a/src/iso19111/common.cpp b/src/iso19111/common.cpp
index f2e4de4c..4606905b 100644
--- a/src/iso19111/common.cpp
+++ b/src/iso19111/common.cpp
@@ -39,6 +39,7 @@
 #include "proj/internal/io_internal.hpp"
 
 #include "proj.h"
+#include "proj_internal.h"
 
 #include <cmath> // M_PI
 #include <cstdlib>
@@ -312,7 +313,7 @@ bool UnitOfMeasure::operator!=(const UnitOfMeasure &other) PROJ_PURE_DEFN {
 //! @cond Doxygen_Suppress
 std::string UnitOfMeasure::exportToPROJString() const {
     if (type() == Type::LINEAR) {
-        auto proj_units = proj_list_units();
+        auto proj_units = pj_list_linear_units();
         for (int i = 0; proj_units[i].id != nullptr; i++) {
             if (::fabs(proj_units[i].factor - conversionToSI()) <
                 1e-10 * conversionToSI()) {
diff --git a/src/iso19111/factory.cpp b/src/iso19111/factory.cpp
index 1c836367..6a707e0d 100644
--- a/src/iso19111/factory.cpp
+++ b/src/iso19111/factory.cpp
@@ -5214,6 +5214,64 @@ std::list<AuthorityFactory::CRSInfo> AuthorityFactory::getCRSInfoList() const {
 
 // ---------------------------------------------------------------------------
 
+//! @cond Doxygen_Suppress
+AuthorityFactory::UnitInfo::UnitInfo()
+    : authName{}, code{}, name{}, category{}, convFactor{}, projShortName{},
+      deprecated{} {}
+//! @endcond
+
+// ---------------------------------------------------------------------------
+
+/** \brief Return the list of units.
+ * @throw FactoryException
+ *
+ * @since 7.1
+ */
+std::list<AuthorityFactory::UnitInfo> AuthorityFactory::getUnitList() const {
+    std::string sql = "SELECT auth_name, code, name, type, conv_factor, "
+                      "proj_short_name, deprecated FROM unit_of_measure";
+    ListOfParams params;
+    if (d->hasAuthorityRestriction()) {
+        sql += " WHERE auth_name = ?";
+        params.emplace_back(d->authority());
+    }
+    sql += " ORDER BY auth_name, code";
+
+    auto sqlRes = d->run(sql, params);
+    std::list<AuthorityFactory::UnitInfo> res;
+    for (const auto &row : sqlRes) {
+        AuthorityFactory::UnitInfo info;
+        info.authName = row[0];
+        info.code = row[1];
+        info.name = row[2];
+        const std::string &raw_category(row[3]);
+        if (raw_category == "length") {
+            info.category = info.name.find(" per ") != std::string::npos
+                                ? "linear_per_time"
+                                : "linear";
+        } else if (raw_category == "angle") {
+            info.category = info.name.find(" per ") != std::string::npos
+                                ? "angular_per_time"
+                                : "angular";
+        } else if (raw_category == "scale") {
+            info.category =
+                info.name.find(" per year") != std::string::npos ||
+                        info.name.find(" per second") != std::string::npos
+                    ? "scale_per_time"
+                    : "scale";
+        } else {
+            info.category = raw_category;
+        }
+        info.convFactor = row[4].empty() ? 0 : c_locale_stod(row[4]);
+        info.projShortName = row[5];
+        info.deprecated = row[6] == "1";
+        res.emplace_back(info);
+    }
+    return res;
+}
+
+// ---------------------------------------------------------------------------
+
 /** \brief Gets the official name from a possibly alias name.
  *
  * @param aliasedName Alias name.
diff --git a/src/proj.h b/src/proj.h
index 75c46fc8..4988e1d0 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -151,6 +151,24 @@ extern "C" {
 #endif
 #endif
 
+#ifdef PROJ_SUPPRESS_DEPRECATION_MESSAGE
+  #define PROJ_DEPRECATED(decl, msg)            decl
+#elif defined(__has_extension)
+  #if __has_extension(attribute_deprecated_with_message)
+    #define PROJ_DEPRECATED(decl, msg)          decl __attribute__ ((deprecated(msg)))
+  #elif defined(__GNUC__)
+    #define PROJ_DEPRECATED(decl, msg)          decl __attribute__ ((deprecated))
+  #else
+    #define PROJ_DEPRECATED(decl, msg)          decl
+  #endif
+#elif defined(__GNUC__)
+  #define PROJ_DEPRECATED(decl, msg)            decl __attribute__ ((deprecated))
+#elif defined(_MSVC_VER)
+  #define PROJ_DEPRECATED(decl, msg)            __declspec(deprecated(msg)) decl
+#else
+  #define PROJ_DEPRECATED(decl, msg)            decl
+#endif
+
 /* The version numbers should be updated with every release! **/
 #define PROJ_VERSION_MAJOR 7
 #define PROJ_VERSION_MINOR 1
@@ -608,7 +626,7 @@ PJ_INIT_INFO PROJ_DLL proj_init_info(const char *initname);
 /* Get lists of operations, ellipsoids, units and prime meridians. */
 const PJ_OPERATIONS       PROJ_DLL *proj_list_operations(void);
 const PJ_ELLPS            PROJ_DLL *proj_list_ellps(void);
-const PJ_UNITS            PROJ_DLL *proj_list_units(void);
+PROJ_DEPRECATED(const PJ_UNITS            PROJ_DLL *proj_list_units(void), "Deprecated by proj_get_units_from_database");
 const PJ_UNITS            PROJ_DLL *proj_list_angular_units(void);
 const PJ_PRIME_MERIDIANS  PROJ_DLL *proj_list_prime_meridians(void);
 
@@ -912,6 +930,39 @@ typedef struct
     int allow_deprecated;
 } PROJ_CRS_LIST_PARAMETERS;
 
+/** \brief Structure given description of a unit.
+ *
+ * This structure may grow over time, and should not be directly allocated by
+ * client code.
+ * @since 7.1
+ */
+typedef struct
+{
+    /** Authority name. */
+    char* auth_name;
+
+    /** Object code. */
+    char* code;
+
+    /** Object name. For example "metre", "US survey foot", etc. */
+    char* name;
+
+    /** Category of the unit: one of "linear", "linear_per_time", "angular",
+     * "angular_per_time", "scale", "scale_per_time" or "time" */
+    char* category;
+
+    /** Conversion factor to apply to transform from that unit to the
+     * corresponding SI unit (metre for "linear", radian for "angular", etc.).
+     * It might be 0 in some cases to indicate no known conversion factor. */
+    double conv_factor;
+
+    /** PROJ short name, like "m", "ft", "us-ft", etc... Might be NULL */
+    char* proj_short_name;
+
+    /** Whether the object is deprecated */
+    int deprecated;
+} PROJ_UNIT_INFO;
+
 
 /**@}*/
 
@@ -1077,6 +1128,15 @@ PROJ_CRS_INFO PROJ_DLL **proj_get_crs_info_list_from_database(
 
 void PROJ_DLL proj_crs_info_list_destroy(PROJ_CRS_INFO** list);
 
+PROJ_UNIT_INFO PROJ_DLL **proj_get_units_from_database(
+                                            PJ_CONTEXT *ctx,
+                                            const char *auth_name,
+                                            const char *category,
+                                            int allow_deprecated,
+                                            int *out_result_count);
+
+void PROJ_DLL proj_unit_list_destroy(PROJ_UNIT_INFO** list);
+
 /* ------------------------------------------------------------------------- */
 
 
diff --git a/src/proj_internal.h b/src/proj_internal.h
index f3e1e2e8..ffc73b06 100644
--- a/src/proj_internal.h
+++ b/src/proj_internal.h
@@ -880,12 +880,15 @@ std::vector<CoordOperation> pj_create_prepared_operations(PJ_CONTEXT *ctx,
                                                      const PJ *source_crs,
                                                      const PJ *target_crs,
                                                      PJ_OBJ_LIST* op_list);
+
 int pj_get_suggested_operation(PJ_CONTEXT *ctx,
                                const std::vector<CoordOperation>& opList,
                                const int iExcluded[2],
                                PJ_DIRECTION direction,
                                PJ_COORD coord);
 
+const PJ_UNITS *pj_list_linear_units();
+
 /* classic public API */
 #include "proj_api.h"
 
diff --git a/src/units.cpp b/src/units.cpp
index 34a71db1..36f2d4c7 100644
--- a/src/units.cpp
+++ b/src/units.cpp
@@ -36,6 +36,12 @@ pj_units[] = {
     {nullptr,      nullptr,                   nullptr,                           0.0}
 };
 
+// For internal use
+const PJ_UNITS *pj_list_linear_units()
+{
+    return pj_units;
+}
+
 const PJ_UNITS *proj_list_units()
 {
     return pj_units;
diff --git a/test/unit/gie_self_tests.cpp b/test/unit/gie_self_tests.cpp
index 720c13ca..6f1b3c32 100644
--- a/test/unit/gie_self_tests.cpp
+++ b/test/unit/gie_self_tests.cpp
@@ -334,7 +334,6 @@ TEST(gie, info_functions) {
 
     const PJ_OPERATIONS *oper_list;
     const PJ_ELLPS *ellps_list;
-    const PJ_UNITS *unit_list;
     const PJ_PRIME_MERIDIANS *pm_list;
 
     char buf[40];
@@ -453,11 +452,6 @@ TEST(gie, info_functions) {
     ASSERT_NE(n, 0U);
 
     n = 0;
-    for (unit_list = proj_list_units(); unit_list->id; ++unit_list)
-        n++;
-    ASSERT_NE(n, 0U);
-
-    n = 0;
     for (pm_list = proj_list_prime_meridians(); pm_list->id; ++pm_list)
         n++;
     ASSERT_NE(n, 0U);
diff --git a/test/unit/test_c_api.cpp b/test/unit/test_c_api.cpp
index f274af57..c984e84e 100644
--- a/test/unit/test_c_api.cpp
+++ b/test/unit/test_c_api.cpp
@@ -3425,6 +3425,48 @@ TEST_F(CApi, proj_get_crs_info_list_from_database) {
 
 // ---------------------------------------------------------------------------
 
+TEST_F(CApi, proj_get_units_from_database) {
+    { proj_unit_list_destroy(nullptr); }
+
+    {
+        auto list = proj_get_units_from_database(nullptr, nullptr, nullptr,
+                                                 true, nullptr);
+        ASSERT_NE(list, nullptr);
+        ASSERT_NE(list[0], nullptr);
+        ASSERT_NE(list[0]->auth_name, nullptr);
+        ASSERT_NE(list[0]->code, nullptr);
+        ASSERT_NE(list[0]->name, nullptr);
+        proj_unit_list_destroy(list);
+    }
+
+    {
+        int result_count = 0;
+        auto list = proj_get_units_from_database(nullptr, "EPSG", "linear",
+                                                 false, &result_count);
+        ASSERT_NE(list, nullptr);
+        EXPECT_GT(result_count, 1);
+        EXPECT_EQ(list[result_count], nullptr);
+        bool found9001 = false;
+        for (int i = 0; i < result_count; i++) {
+            EXPECT_EQ(std::string(list[i]->auth_name), "EPSG");
+            if (std::string(list[i]->code) == "9001") {
+                EXPECT_EQ(std::string(list[i]->name), "metre");
+                EXPECT_EQ(std::string(list[i]->category), "linear");
+                EXPECT_EQ(list[i]->conv_factor, 1.0);
+                ASSERT_NE(list[i]->proj_short_name, nullptr);
+                EXPECT_EQ(std::string(list[i]->proj_short_name), "m");
+                EXPECT_EQ(list[i]->deprecated, 0);
+                found9001 = true;
+            }
+            EXPECT_EQ(list[i]->deprecated, 0);
+        }
+        EXPECT_TRUE(found9001);
+        proj_unit_list_destroy(list);
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 TEST_F(CApi, proj_normalize_for_visualization) {
 
     {
diff --git a/test/unit/test_factory.cpp b/test/unit/test_factory.cpp
index c7ae458e..aee2f572 100644
--- a/test/unit/test_factory.cpp
+++ b/test/unit/test_factory.cpp
@@ -1401,16 +1401,18 @@ class FactoryWithTmpDatabase : public ::testing::Test {
     void populateWithFakeEPSG() {
 
         ASSERT_TRUE(execute("INSERT INTO unit_of_measure "
-                            "VALUES('EPSG','9001','metre','length',1.0,0);"))
+                            "VALUES('EPSG','9001','metre','length',1.0,NULL,"
+                            "0);"))
             << last_error();
         ASSERT_TRUE(execute("INSERT INTO unit_of_measure "
                             "VALUES('EPSG','9102','degree','angle',1."
-                            "74532925199432781271e-02,0);"))
+                            "74532925199432781271e-02,NULL,0);"))
             << last_error();
         ASSERT_TRUE(execute(
             "INSERT INTO unit_of_measure VALUES('EPSG','9122','degree "
             "(supplier to "
-            "define representation)','angle',1.74532925199432781271e-02,0);"))
+            "define representation)','angle',1.74532925199432781271e-02,NULL,"
+            "0);"))
             << last_error();
         ASSERT_TRUE(
             execute("INSERT INTO area "
@@ -1470,7 +1472,8 @@ class FactoryWithTmpDatabase : public ::testing::Test {
             << last_error();
 
         ASSERT_TRUE(execute("INSERT INTO unit_of_measure "
-                            "VALUES('EPSG','9201','unity','scale',1.0,0);"))
+                            "VALUES('EPSG','9201','unity','scale',1.0,"
+                            "NULL,0);"))
             << last_error();
 
         ASSERT_TRUE(execute(
@@ -1547,7 +1550,7 @@ class FactoryWithTmpDatabase : public ::testing::Test {
 
         ASSERT_TRUE(execute(
             "INSERT INTO unit_of_measure VALUES('EPSG','9110','sexagesimal "
-            "DMS','angle',NULL,0);"))
+            "DMS','angle',NULL,NULL,0);"))
             << last_error();
 
         ASSERT_TRUE(execute(
@@ -2933,7 +2936,7 @@ TEST(factory, getCRSInfoList) {
         auto list = factory->getCRSInfoList();
         EXPECT_GT(list.size(), 1U);
         bool foundEPSG = false;
-        bool foundIGNF = true;
+        bool foundIGNF = false;
         bool found4326 = false;
         for (const auto &info : list) {
             foundEPSG |= info.authName == "EPSG";
@@ -3023,4 +3026,73 @@ TEST(factory, getCRSInfoList) {
         EXPECT_TRUE(found6871);
     }
 }
+
+// ---------------------------------------------------------------------------
+
+TEST(factory, getUnitList) {
+    auto ctxt = DatabaseContext::create();
+    {
+        auto factory = AuthorityFactory::create(ctxt, std::string());
+        auto list = factory->getUnitList();
+        EXPECT_GT(list.size(), 1U);
+        bool foundEPSG = false;
+        bool foundPROJ = false;
+        bool found1027 = false;
+        bool found1028 = false;
+        bool found1032 = false;
+        bool found1036 = false;
+        bool found9001 = false;
+        bool found9101 = false;
+        for (const auto &info : list) {
+            foundEPSG |= info.authName == "EPSG";
+            foundPROJ |= info.authName == "PROJ";
+            if (info.authName == "EPSG" && info.code == "1027") {
+                EXPECT_EQ(info.name, "millimetres per year");
+                EXPECT_EQ(info.category, "linear_per_time");
+                found1027 = true;
+            } else if (info.authName == "EPSG" && info.code == "1028") {
+                EXPECT_EQ(info.name, "parts per billion");
+                EXPECT_EQ(info.category, "scale");
+                found1028 = true;
+            } else if (info.authName == "EPSG" && info.code == "1032") {
+                EXPECT_EQ(info.name, "milliarc-seconds per year");
+                EXPECT_EQ(info.category, "angular_per_time");
+                found1032 = true;
+            } else if (info.authName == "EPSG" && info.code == "1036") {
+                EXPECT_EQ(info.name, "unity per second");
+                EXPECT_EQ(info.category, "scale_per_time");
+                found1036 = true;
+            } else if (info.authName == "EPSG" && info.code == "9001") {
+                EXPECT_EQ(info.name, "metre");
+                EXPECT_EQ(info.category, "linear");
+                EXPECT_EQ(info.convFactor, 1.0);
+                EXPECT_EQ(info.projShortName, "m");
+                EXPECT_FALSE(info.deprecated);
+                found9001 = true;
+            } else if (info.authName == "EPSG" && info.code == "9101") {
+                EXPECT_EQ(info.name, "radian");
+                EXPECT_EQ(info.category, "angular");
+                EXPECT_FALSE(info.deprecated);
+                found9101 = true;
+            }
+        }
+        EXPECT_TRUE(foundEPSG);
+        EXPECT_TRUE(foundPROJ);
+        EXPECT_TRUE(found1027);
+        EXPECT_TRUE(found1028);
+        EXPECT_TRUE(found1032);
+        EXPECT_TRUE(found1036);
+        EXPECT_TRUE(found9001);
+        EXPECT_TRUE(found9101);
+    }
+    {
+        auto factory = AuthorityFactory::create(ctxt, "EPSG");
+        auto list = factory->getUnitList();
+        EXPECT_GT(list.size(), 1U);
+        for (const auto &info : list) {
+            EXPECT_EQ(info.authName, "EPSG");
+        }
+    }
+}
+
 } // namespace