[GRASS-dev] [GRASS GIS] #3930: reprojection error in r.proj / GRASS 7.8.1 -- N-S-coordinates interchanged with W-E

[GRASS GIS]

#3930: reprojection error in r.proj / GRASS 7.8.1 -- N-S-coordinates interchanged
with W-E
--------------------------------+---------------------------------
 Reporter:  guilo               |      Owner:  grass-dev@…
     Type:  defect              |     Status:  new
 Priority:  normal              |  Milestone:
Component:  Projections/Datums  |    Version:  git-releasebranch78
 Keywords:                      |        CPU:  x86-64
 Platform:  Linux               |
--------------------------------+---------------------------------
 = Description =

 There is observed a serious error in map reprojection, using r.proj,
 resulting in an interchange of N-S-coordinates with those of East-West.

 The error occurs in GRASS version 7.8 (proj4 version 6.2, gdal version
 2.42), in the reprojection with r.proj, from a newly created source map
 projection, to an existent target map projection. Repeating the same
 procedure, but using a formerly created source map projection (same
 projection, but prior to GRASS 7.6), the maps are reprojected in a correct
 way.

 Under GRASS 7.6, the reprojection procedure is carried out correctly, for
 both source map projection versions.

 == Minimal working example ==

 The example is based on the reprojection of a small section of a Landsat 8
 image, from WGS84 / UTM 20N projection, into POSGAR 2007 / Argentina 4
 projection. The file "testLandsatUTM20Nsection.tif" is attached to this
 mail.

 1. system: debian linux 10 (buster), gdal: 2.42, proj4: 6.2

 2. new source map projection, created under GRASS 7.8:

  (Thu Oct  3 07:22:23 2019)\\
  g.proj -p\\
  -PROJ_INFO-------------------------------------------------\\
  name       : WGS 84 / UTM zone 20N\\
  datum      : wgs84\\
  ellps      : wgs84\\
  proj       : utm\\
  zone       : 20\\
  no_defs    : defined\\
  towgs84    : 0.000,0.000,0.000\\
  -PROJ_EPSG-------------------------------------------------\\
  epsg       : 32620\\
  -PROJ_UNITS------------------------------------------------\\
  unit       : meter\\
  units      : meters\\
  meters     : 1\\
  (Thu Oct  3 07:22:23 2019) Command finished (0 sec)


 3. old source map projection, creation with GRASS prior to 7.6)

  (Thu Oct  3 07:31:21 2019)\\
  g.proj -p\\
  -PROJ_INFO-------------------------------------------------\\
  name       : Universal Transverse Mercator\\
  proj       : utm\\
  datum      : wgs84\\
  ellps      : wgs84\\
  zone       : 20\\
  no_defs    : defined\\
  towgs84    : 0.000,0.000,0.000\\
  -PROJ_UNITS------------------------------------------------\\
  unit       : meter\\
  units      : meters\\
  meters     : 1\\
  (Thu Oct  3 07:31:22 2019) Command finished (0 sec)

 4. target map projection:

  (Thu Oct  3 07:19:24 2019)\\
  g.proj -p\\
  -PROJ_INFO-------------------------------------------------\\
  name       : POSGAR 2007 / Argentina 4\\
  ellps      : grs80\\
  proj       : tmerc\\
  lat_0      : -90\\
  lon_0      : -63\\
  k          : 1\\
  x_0        : 4500000\\
  y_0        : 0\\
  towgs84    : 0,0,0,0,0,0,0\\
  no_defs    : defined\\
  -PROJ_EPSG-------------------------------------------------\\
  epsg       : 5346\\
  -PROJ_UNITS------------------------------------------------\\
  unit       : meter\\
  units      : meters\\
  meters     : 1\\
  (Thu Oct  3 07:19:24 2019) Command finished (0 sec)


 5. Reprojection results:

    5.1 correct reprojection with GRASS 7.6.2, from both, old and new
 source projection

     a) from old source projection

     (Sat Nov  2 05:54:58 2019)\\
     r.proj -p location=L8utm20N mapset=PERMANENT
 input=testLandsatUTM20Nsection\\
     Source cols: 500\\
     Source rows: 200\\
     Local north: 6959148.60238428\\
     Local south: 6953146.20142391\\
     Local west: 4310724.28971634\\
     Local east: 4325730.29211732\\
     Input map <testLandsatUTM20Nsection at PERMANENT> in location
 <L8utm20N>:\\
     (Sat Nov  2 05:54:59 2019) Command finished (0 sec)\\

     b) from new source projection

     r.proj -p location=L8utm20N2019 input=testLandsatUTM20Nsection\\
     Source cols: 500\\
     Source rows: 200\\
     Local north: 6959148.60238428\\
     Local south: 6953146.20142391\\
     Local west: 4310724.28971634\\
     Local east: 4325730.29211732\\
     Input map <testLandsatUTM20Nsection at PERMANENT> in location
 <L8utm20N2019>:\\
     (Sat Nov  2 05:56:10 2019) Command finished (0 sec)\\

  5.2 incorrect reprojection in GRASS 7.8.1, from new source projection

   N/S coordinates are interchanged with those of W/E

   r.proj -p location=L8utm20N2019 input=testLandsatUTM20Nsection\\
   Input map <testLandsatUTM20Nsection at PERMANENT> in location
 <L8utm20N2019>:\\
   Source cols: 500\\
   Source rows: 200\\
   Local north: 4325730.29211624\\
   Local south: 4310724.28971522\\
   Local west: 6953146.20150881\\
   Local east: 6959148.60246907\\
   (Sat Nov  2 06:01:24 2019) Command finished (0 sec)\\

  5.3 correct reprojection in GRASS 7.8.1, from old source projection

   (Sat Nov  2 05:59:57 2019)\\
   r.proj -p location=L8utm20N mapset=PERMANENT
 input=testLandsatUTM20Nsection\\
   Source cols: 500\\
   Source rows: 200\\
   Local north: 6959148.60238337\\
   Local south: 6953146.201423\\
   Local west: 4310724.28971655\\
   Local east: 4325730.29211746\\
   Input map <testLandsatUTM20Nsection at PERMANENT> in location <L8utm20N>:\\
   (Sat Nov  2 05:59:58 2019) Command finished (0 sec)\\

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/3930>
GRASS GIS <https://grass.osgeo.org>