[GRASS-dev] [GRASS GIS] #2654: r.thin crashes

[GRASS GIS]

#2654: r.thin crashes
----------------------+-----------------------------------------------------
 Reporter:  pairmand  |       Owner:  grass-dev@…              
     Type:  defect    |      Status:  new                      
 Priority:  normal    |   Milestone:  7.0.1                    
Component:  Raster    |     Version:  7.0.0                    
 Keywords:  r.thin    |    Platform:  MSWindows 7              
      Cpu:  x86-64    |  
----------------------+-----------------------------------------------------

Comment(by pairmand):

 Thank you both for your help - I think it was actually multiple unrelated
 problems.
 If I create a new location/mapset then g.region -p produces;

 {{{
 g.region -p
 projection: 99 (Transverse Mercator)
 zone:       0
 datum:      nzgd2k
 ellipsoid:  grs80
 north:      1
 south:      0
 west:       0
 east:       1
 nsres:      1
 ewres:      1
 rows:       1
 cols:       1
 cells:      1
 (Mon Apr 20 11:50:24 2015) Command finished (0 sec)
 }}}

 If I then import the Imagine file with extend region and repeat I get;

 {{{
 r.in.gdal input=D:\temp_work\temukaSub_rasterEdges.img
 output=temukaSub_rasterEdges -e
 WARNING: Datum <NZGD2000_NTv2> not recognised by GRASS and no parameters
 found
 Raster map <temukaSub_rasterEdges> created.
 Region for the current mapset updated
 r.in.gdal complete.
 (Mon Apr 20 11:53:07 2015) Command finished (0 sec)
 (Mon Apr 20 11:53:20 2015)
 g.region -p
 projection: 99 (Transverse Mercator)
 zone:       0
 datum:      nzgd2k
 ellipsoid:  grs80
 north:      5117010
 south:      0
 west:       0
 east:       1474010
 nsres:      1
 ewres:      1
 rows:       5117010
 cols:       1474010
 cells:      7542523910100
 (Mon Apr 20 11:53:20 2015) Command finished (0 sec)
 }}}


 That is, the map coordinates seem to be set to the north east corner but
 south, west, cols and rows are all incorrect. This appears to be a bug
 importing from the Imagine file using the gdal importer. If I try and thin
 at this point then the thin crashes - see screenshot.
 [[Image(http://trac.osgeo.org/grass/attachment/ticket/2654/GrassCrash.JPG)]]

 However, if I use g.region to correct the above I get a result that looks
 good;

 {{{
 g.region raster=temukaSub_rasterEdges
 (Mon Apr 20 12:03:08 2015) Command finished (0 sec)
 (Mon Apr 20 12:03:22 2015)
 g.region -p
 projection: 99 (Transverse Mercator)
 zone:       0
 datum:      nzgd2k
 ellipsoid:  grs80
 north:      5117010
 south:      5108000
 west:       1463000
 east:       1474010
 nsres:      10
 ewres:      10
 rows:       901
 cols:       1101
 cells:      992001
 (Mon Apr 20 12:03:22 2015) Command finished (0 sec)
 }}}

 At this point running r.thin still produces an error and only appears to
 have processed the middle section of the image.

 {{{
 ...
 Thinning not completed, consider to increase 'iterations' parameter.
 Output map 901 rows X 1101 columns
 Window 901 rows X 1101 columns
 (Mon Apr 20 12:04:46 2015) Command finished (17 sec)
 }}}

 Setting 0 as null cells fixes that problem also;

 {{{
 r.null map=temukaSub_rasterEdges setnull=0
 (Mon Apr 20 12:06:49 2015) Command finished (0 sec)
 (Mon Apr 20 12:07:20 2015)
 r.thin --overwrite input=temukaSub_rasterEdges at canTest
 output=temukaThinned
 Raster map <temukaSub_rasterEdges at canTest> - 901 rows X 1101 columns
 Bounding box:  l = 2, r = 1102, t = 2, b = 902
 Pass number 1
 Deleted 68577 pixels
 Pass number 2
 Deleted 2270 pixels
 Pass number 3
 Deleted 37 pixels
 Pass number 4
 Deleted 0 pixels
 Thinning completed successfully.
 Output map 901 rows X 1101 columns
 Window 901 rows X 1101 columns
 (Mon Apr 20 12:07:21 2015) Command finished (0 sec)
 }}}

 So I'm now a happy camper - but suggest there is a bug in the raster
 importer, in that it doesn't set the extent correctly, and the
 documentation of r.thin definitely needs to clarify that it is working on
 nulls not zeros.

 Thanks again for your help.
 David

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/2654#comment:3>
GRASS GIS <http://grass.osgeo.org>