From 5f6fac3afdb03aef5a26ce5f60c10ed612fa6fc2 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Thu, 17 Jun 2021 17:53:11 +0200
Subject: proj_trans/cs2cs: If two operations have the same accuracy, use the
 one that is contained within a larger one

Relates to https://github.com/OSGeo/gdal/issues/3998

Before that change, cs2cs on a NAD83(HARN) to WGS84 transformation would
use the "NAD83(HARN) to WGS 84 (1)" transformation (a null Helmert
shift) that is valid for whole US, including non-CONUS areas, even when
used on points located on CONUS that has a "NAD83(HARN) to WGS 84 (3)"
transformation (non-null Helmert shift) with same accuracy (1m).

But if doing  EPSG:2874 "NAD83(HARN) / California zone 5 (ftUS)" to
WGS84, we would use this later "NAD83(HARN) to WGS 84 (3)"
transformation because the area of use of EPSG:2874 restricts to CONUS.
This isn't consistant.

With that change, we now have more consistent behavior, even if it can
be argued which of the 2 transformations is the best...

$ echo 34 -120 | src/cs2cs -d 8 EPSG:4326 "NAD83(HARN)" | src/cs2cs "NAD83(HARN)"  EPSG:2874
5955507.74	1828410.98 0.00

$ echo 34 -120 | src/cs2cs  EPSG:4326   EPSG:2874
5955507.74	1828410.98 0.00
---
 test/cli/testvarious | 6 ++++++
 test/cli/tv_out.dist | 3 +++
 2 files changed, 9 insertions(+)

(limited to 'test/cli')

diff --git a/test/cli/testvarious b/test/cli/testvarious
index e88cf68b..6e9cd43c 100755
--- a/test/cli/testvarious
+++ b/test/cli/testvarious
@@ -1047,6 +1047,12 @@ $EXE -E EPSG:2636 "WGS 84" >> ${OUT} <<EOF
 5540944.47  500000.001
 EOF
 
+echo  "##############################################################" >> ${OUT}
+echo  "Check that we select the operation that has the smallest area of use, when 2 have the same accuracy" >> ${OUT}
+$EXE -E EPSG:4326 "NAD83(HARN)" >> ${OUT} <<EOF
+34 -120
+EOF
+
 
 # Done!
 # do 'diff' with distribution results
diff --git a/test/cli/tv_out.dist b/test/cli/tv_out.dist
index 44926677..9bb85933 100644
--- a/test/cli/tv_out.dist
+++ b/test/cli/tv_out.dist
@@ -504,3 +504,6 @@ Check that we can use a transformation spanning the antimeridian (should use Pul
 Check that we can use a transformation spanning the antimeridian (should use Pulkovo 1942 to WGS 84 (20))
 5540944.47  499999.999	49d59'59.36"N	179d59'52.133"W 0.000
 5540944.47  500000.001	49d59'59.36"N	179d59'52.133"W 0.000
+##############################################################
+Check that we select the operation that has the smallest area of use, when 2 have the same accuracy
+34 -120	33d59'59.983"N	119d59'59.955"W 0.000
-- 
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