[GRASS-dev] Possible bug in r.out.gdal?

Markus Metz markus.metz.giswork at googlemail.com
Tue Aug 11 10:25:00 EDT 2009


 From the DTED specs:

A data file of DTED Level 0, DTED Level 1 or
DTED Level 2 is a 1° by 1° cell defined by whole degree latitude and
longitude
lines on WGS. A DTED file shall not cross whole degree latitude or longitude
lines.

Matrix intervals for DTED Level 0.
ZONE LATITUDE latitude x longitude INTERVAL
I 0° - 50° North-South 30 x 30 seconds
II 50° - 70° North-South 30 x 60 seconds
III 70° - 75° North-South 30 x 90 seconds
IV 75° - 80° North-South 30 x 120 seconds
V 80° - 90° North-South 30 x 180 seconds

Matrix intervals for DTED Level 1.
ZONE LATITUDE latitude x longitude INTERVAL
I 0° - 50° North-South 3 x 3 seconds
II 50° - 70° North-South 3 x 6 seconds
III 70° - 75° North-South 3 x 9 seconds
IV 75° - 80° North-South 3 x 12 seconds
V 80° - 90° North-South 3 x 18 seconds

Matrix intervals for DTED Level 2.
ZONE LATITUDE latitude x longitude INTERVAL
I 0° - 50° North-South 1 x 1 seconds
II 50° - 70° North-South 1 x 2 seconds
III 70° - 75° North-South 1 x 3 seconds
IV 75° - 80° North-South 1 x 4 seconds
V 80° - 90° North-South 1 x 6 seconds

No idea how strict the gdal driver for DTED is, but it seems that it is
very strict and won't work without reprojection, followed by setting
region extends and resolution according to the desired DTED level.

Markus M


Soeren Gebbert wrote:
> Dear Devs,
> i found a strange behavior in r.out.gdal while updating the GRASS test 
> suite.
>
> Im using the grass6.4svn snapshot: 
> grass-6.4.svn_src_snapshot_2009_08_01.tar.gz.
> on openSuse 10.3 Linux 2.6.22.19-0.2-bigsmp
> gdal version 1.6.1
>
> The test i am implementing tries to export a DCELL raster map (named 
> elevation ) to a DTED file with r.out.gdal.
> r.out.gdal reports plenty of errors (all of the same type) an exits 
> with return code 0.
> A dted file is created, but im not sure if it is valid.
> Exporting the same file with r.out.gdal in ENVI and ELAS formats seems 
> to work correctly.
>
> These steps are performed:
>
> GRASS 6.4.0svn > g.region -p
> projection: 1 (UTM)
> zone:       32
> datum:      wgs84
> ellipsoid:  wgs84
> north:      5582000
> south:      5580000
> west:       400000
> east:       402000
> nsres:      20
> ewres:      20
> rows:       100
> cols:       100
> cells:      10000
>
> GRASS 6.4.0svn > r.info <http://r.info> elevation
>  +----------------------------------------------------------------------------+
>  | Layer:    elevation                      Date: Sun Apr 30 12:48:58 
> 2006    |
>  | Mapset:   PERMANENT                      Login of Creator: 
> soeren          |
>  | Location: 
> TestLocation                                                     |
>  | DataBase: 
> /1/gebbert/src/GRASS_Testsuite                                   |
>  | Title:     ( elevation 
> )                                                   |
>  | Timestamp: 
> none                                                            |
>  |----------------------------------------------------------------------------|
>  |                                                                            
> |
>  |   Type of Map:  raster               Number of Categories: 
> 255             |
>  |   Data Type:    
> DCELL                                                      |
>  |   Rows:         
> 100                                                        |
>  |   Columns:      
> 100                                                        |
>  |   Total Cells:  
> 10000                                                      |
>  |        Projection: UTM (zone 
> 32)                                           |
>  |            N:    5582000    S:    5580000   Res:    
> 20                     |
>  |            E:     402000    W:     400000   Res:    
> 20                     |
>  |   Range of data:    min = 68.246322  max = 
> 363.529491                      |
>  |                                                                            
> |
>  |   Data 
> Description:                                                        |
>  |    generated by 
> r.mapcalc                                                  |
>  |                                                                            
> |
>  |   
> Comments:                                                                |
>  |    sin(col() * 5) * col() + cos(row() * 5) * row() + 
> 200                   |
>  |                                                                            
> |
>  +----------------------------------------------------------------------------+
>
>
> GRASS 6.4.0svn > r.out.gdal --verbose format=DTED type=Float32 
> input=elevation output=/tmp/test.dted 
> ....
> ERROR 5: Access window out of range in RasterIO().  Requested
> (0,994) of size 201x1 on raster of 100x100.
> ERROR 5: Access window out of range in RasterIO().  Requested
> (0,995) of size 201x1 on raster of 100x100.
> ERROR 5: Access window out of range in RasterIO().  Requested
> (0,996) of size 201x1 on raster of 100x100.
> More than 1000 errors or warnings have been reported. No more will be 
> reported from now.
> r.out.gdal complete.
>
>
> GRASS 6.4.0svn > gdalinfo -nomd -noct -stats /tmp/test.dted
> Driver: DTED/DTED Elevation Raster
> Files: /tmp/test.dted
>        /tmp/test.dted.aux.xml
> Size is 201, 1201
> Coordinate System is:
> GEOGCS["WGS 84",
>     DATUM["WGS_1984",
>         SPHEROID["WGS 84",6378137,298.257223563]],
>     PRIMEM["Greenwich",0],
>     UNIT["degree",0.0174532925199433],
>     AUTHORITY["EPSG","4326"]]
> Origin = (399.997500000000002,559.000416666666638)
> Pixel Size = (0.005000000000000,-0.000833333333333)
> Corner Coordinates:
> Upper Left  (     399.998,     559.000) (399d59'51.00"E,559d 0'1.50"N)
> Lower Left  (     399.998,     558.000) (399d59'51.00"E,557d59'58.50"N)
> Upper Right (     401.002,     559.000) (401d 0'9.00"E,559d 0'1.50"N)
> Lower Right (     401.002,     558.000) (401d 0'9.00"E,557d59'58.50"N)
> Center      (     400.500,     558.500) (400d30'0.00"E,558d30'0.00"N)
> Band 1 Block=1x1201 Type=Int16, ColorInterp=Palette
>   Min=0.000 Max=0.000
>   Minimum=0.000, Maximum=0.000, Mean=0.000, StdDev=0.000
>   NoData Value=-32767
>   Unit Type: m
>   Color Table (RGB with 365 entries)
>
>
> Any suggestions what i did wrong?
> Maybe the region settings are incompatible with the dted output 
> coordinate system?
> Or is this a correct behavior of r.out.gdal?
>
> Thanks in advance
> best regards
> Soeren
>
>
>
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>
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