Region for 3s tiles fails if not multiple of 3s (#4124)

* Regino for 3s tiles fails if not multiple of 2s

See form post for details. This PR simply adds a failing test.

* Add orig PS

* Pre-download two 3s tiles

* Cache two tiles of earth_relief_03s data

* Remove one unnecessary comment

Co-authored-by: Dongdong Tian <[email protected]>

Author: PaulWessel

ci/azure-pipelines-mac.yml

@@ -102,6 +102,9 @@ steps:
     gmt which -Ga $data
     gmt which -Ga $data
     gmt get -Dcache
+    # Download extra tiles for tests
+    # test/grdimage/rounding.sh
+    gmt grdcut -R3:57/4:18/44:00/44:15 @earth_relief_03s -G/dev/null
   displayName: Download remote data
   condition: ne(variables['CACHE_CACHEDATA_RESTORED'], true)
 

test/grdimage/rounding.ps

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Failing script while fixing https://forum.generic-mapping-tools.org/t/error-pygmt-gmtcliberror-module-grdimage-failed-with-status-code-78/829
+# Now reported as issue https://github.com/GenericMappingTools/gmt/pull/4130
+
+gmt begin rounding ps
+	gmt subplot begin 2x1 -SCb -SRl -Bwsne -Fs10c/0 -R3:57/4:18/44:00/44:15 -JM10c -X5c
+		gmt grdimage -R3:57/4:18/44:00/44:15 -JM? @earth_relief_03s -Cgeo -I -c0
+		gmt grdimage -R3.970/4.270/44.000/44.250 -JM? @earth_relief_03s -Cgeo -I -c1
+	gmt subplot end
+gmt end show