[GRASS-dev] [GRASS GIS] #2878: "v.in.ogr -i" throws an error when importing a GeoJSON file containing a single point.

[GRASS GIS]

#2878: "v.in.ogr -i" throws an error when importing a GeoJSON file containing a
single point.
--------------------------+-------------------------------
  Reporter:  pmav99       |      Owner:  grass-dev@…
      Type:  defect       |     Status:  new
  Priority:  normal       |  Milestone:
 Component:  Vector       |    Version:  unspecified
Resolution:               |   Keywords:  v.in.ogr v.import
       CPU:  Unspecified  |   Platform:  Unspecified
--------------------------+-------------------------------
Changes (by mlennert):

 * milestone:  7.0.4 =>


Comment:

 Replying to [comment:4 pmav99]:
 > 2. These are the contents of the file. This is directly created by
 GRASS/GDAL:
 > {{{
 > GRASS 7.0.3svn (damflood):~/repo > cat sample.json
 > {
 > "type": "FeatureCollection",
 > "crs": { "type": "name", "properties": { "name":
 "urn:ogc:def:crs:OGC:1.3:CRS84" } },
 > "features": [
 > { "type": "Feature", "properties": { "cat": 1 }, "geometry": { "type":
 "Point", "coordinates": [ -78.690549087210798, 35.769783222348899 ] } },
 > { "type": "Feature", "properties": { "cat": 2 }, "geometry": { "type":
 "Point", "coordinates": [ -78.687924462941851, 35.769783222348899 ] } }
 > ]
 > }
 > }}}

 [...]

 > 5. Trying to create a new location using `v.in.ogr -i` fails. This
 failure is actually the reason that `v.import` fails too (step 3):
 > {{{
 > v.in.ogr -i --verbose input=/home/grassuser/repo/sample.json output=qwer
 location=new_location
 > Location <new_location> created
 > ERROR: Syntax error in cell header
 > }}}

 Interestingly, when I convert the json file to shape before import, I get
 the same error:


 {{{
 v.in.ogr -i in=test.json location=new_location1 --verbose
 ATTENTION: All available OGR layers will be imported into vector map
            <OGRGeoJSON>
 Location <new_location1> created
 ERREUR :Syntax error in cell header
 }}}

 then

 {{{
 ogr2ogr test.shp test.json
 }}}

 and


 {{{
 v.in.ogr -i in=test.shp location=new_location2 --verbose
 ATTENTION: All available OGR layers will be imported into vector map
 <test>
 Location <new_location2> created
 ERREUR :Syntax error in cell header
 }}}

 I also opened the json file in QGIS, saved as a new shapefile and tried to
 import that: same error.

 IIUC the error comes from the fact that the Y coordinates are strictly
 identical and that thus N = S in the DEFAULT_WIND & WIND files and GRASS
 has trouble dealing with a mapset with 0 resolution in any direction...

 The following hack let's you import the file, but this is not a complete
 solution. One question we have to answer is whether GRASS should allow the
 creation of mapsets with 0 resolution in any direction, and, if not (as I
 think it should be), then what would be a reasonable default when creating
 a location from a file containing data with identical coordinates in
 either of the directions or with just one point.


 {{{
 Index: vector/v.in.ogr/main.c
 ===================================================================
 --- vector/v.in.ogr/main.c      (révision 67579)
 +++ vector/v.in.ogr/main.c      (copie de travail)
 @@ -535,6 +535,8 @@
      if ((OGR_L_GetExtent(Ogr_layer, &oExt, 1)) == OGRERR_NONE) {
         cellhd.north = ymax = oExt.MaxY;
         cellhd.south = ymin = oExt.MinY;
 +        if (cellhd.north == cellhd.south)
 +               cellhd.north += 0.0001;
         cellhd.west = xmin = oExt.MinX;
         cellhd.east = xmax = oExt.MaxX;
         cellhd.rows = 20;       /* TODO - calculate useful values */
 }}}

--
Ticket URL: <http://trac.osgeo.org/grass/ticket/2878#comment:10>
GRASS GIS <https://grass.osgeo.org>