Implement RFC 2: Initial integration of "GDAL SRS barn" work

This work mostly consists of:
- a C++ implementation of the ISO-19111:2018 / OGC Topic 2
  "Referencing by coordinates" classes to represent Datums,
  Coordinate systems, CRSs (Coordinate Reference Systems) and
  Coordinate Operations.
- methods to convert between this C++ modeling and WKT1, WKT2
  and PROJ string representations of those objects
- management and query of a SQLite3 database of CRS and Coordinate Operation definition
- a C API binding part of those capabilities

This is all-in-one squashed commit of the work of
https://github.com/OSGeo/proj.4/pull/1040

1 files changed, 23 insertions, 0 deletions

diff --git a/data/sql/grid_transformation_custom.sql b/data/sql/grid_transformation_custom.sql
new file mode 100644
index 00000000..a43312fe
--- /dev/null
+++ b/data/sql/grid_transformation_custom.sql
@@ -0,0 +1,23 @@
+-- This file is hand generated.
+
+INSERT INTO "grid_transformation" VALUES(
+    'PROJ','EPSG_5799_TO_EPSG_4937','DVR90 height to ETRS89',
+    NULL,NULL,
+    'PROJ','HEIGHT_TO_GEOGRAPHIC3D','GravityRelatedHeight to Geographic3D',
+    'EPSG','5799', -- source CRS (DVR90 height)
+    'EPSG','4937', -- target CRS (ETRS89)
+    'EPSG','3237', -- area of use: Denmark onshore
+    NULL,
+    'EPSG','8666','Geoid (height correction) model file','dvr90.gtx',
+    NULL,NULL,NULL,NULL,NULL,NULL,0);
+
+INSERT INTO "grid_transformation" VALUES(
+    'PROJ','EPSG_5733_TO_EPSG_4937','DNN height to ETRS89',
+    NULL,NULL,
+    'PROJ','HEIGHT_TO_GEOGRAPHIC3D','GravityRelatedHeight to Geographic3D',
+    'EPSG','5733', -- source CRS (DNN height)
+    'EPSG','4937', -- target CRS (ETRS89)
+    'EPSG','3237', -- area of use: Denmark onshore
+    NULL,
+    'EPSG','8666','Geoid (height correction) model file','dnn.gtx',
+    NULL,NULL,NULL,NULL,NULL,NULL,0);