[GRASS-dev] limits of r.patch

[Markus Metz]

On Wed, Jul 18, 2012 at 9:00 AM, Margherita Di Leo
<dileomargherita at gmail.com> wrote:
> Hi,
>
> On Tue, Jul 17, 2012 at 4:51 PM, Margherita Di Leo
> <dileomargherita at gmail.com> wrote:
>>
>>
>> Now tried:
>>  gdalbuildvrt -input_file_list elenco_aster_europa mosaic.vrt
>> (all in the same folder)
>>
>> then in GRASS:
>>
>> GRASS 6.4.3svn (ASTER_GDEM):~ > r.external
>> input=/forest/ASTER-GDEM/Dem_lzw/mosaic.vrt output=mosaic --verbose
>>
>> Projection of input dataset and current location appear to match
>> Proceeding with import...
>>
>> Importing band 1 of 1...
>> Setting grey color table for <mosaic> (data range)
>> Creating support files for mosaic
>>
>> Link to raster map <mosaic> created
>> GRASS 6.4.3svn (ASTER_GDEM):~ > r.info map=mosaic
>>
>> +----------------------------------------------------------------------------+
>>  | Layer:    mosaic                         Date: Tue Jul 17 16:49:06 2012
>> |
>>
>>  | Mapset:   PERMANENT                      Login of Creator: leomarg
>> |
>>  | Location: ASTER_GDEM
>> |
>>  | DataBase: /forest/GRASS/grassdata
>> |
>>  | Title:     ( mosaic )
>> |
>>
>>  | Timestamp: none
>> |
>>
>> |----------------------------------------------------------------------------|
>>  |
>> |
>>  |   Type of Map:  raster               Number of Categories: 0
>> |
>>  |   Data Type:    CELL
>> |
>>  |   Rows:         140401
>> |
>>  |   Columns:      198001
>> |
>>  |   Total Cells:  27799538401
>> |
>>  |        Projection: Latitude-Longitude
>> |
>>  |            N: 72:00:00.5N    S: 32:59:59.5N   Res: 0:00:01
>> |
>>  |            E: 44:00:00.5E    W: 11:00:00.5W   Res: 0:00:01
>> |
>>  |   Range of data:    min = 0  max = 0
>> |
>>
>>  |
>> |
>>  |   Data Description:
>> |
>>  |    generated by r.external
>> |
>>  |
>> |
>>  |   Comments:
>> |
>>  |    r.external input="/forest/ASTER-GDEM/Dem_lzw/mosaic.vrt"
>> output="mos\   |
>>  |    aic"
>> |
>>  |
>> |
>>
>> +----------------------------------------------------------------------------+
>>
>
> I've imported the same map with r.in.gdal:
>
> r.in.gdal input=/forest/ASTER-GDEM/Dem_lzw/mosaic.vrt output=mosaic
> --overwrite
>
> r.info map=mosaic
>
> +----------------------------------------------------------------------------+
>  | Layer:    mosaic                         Date: Tue Jul 17 17:57:31 2012
> |
>
>  | Mapset:   PERMANENT                      Login of Creator: leomarg
> |
>  | Location: ASTER_GDEM
> |
>  | DataBase: /forest/GRASS/grassdata
> |
>  | Title:     ( mosaic )
> |
>  | Timestamp: none
> |
>
> |----------------------------------------------------------------------------|
>  |
> |
>  |   Type of Map:  raster               Number of Categories: 6518
> |
>
>  |   Data Type:    CELL
> |
>  |   Rows:         140401
> |
>  |   Columns:      198001
> |
>  |   Total Cells:  27799538401
> |
>  |        Projection: Latitude-Longitude
> |
>  |            N: 72:00:00.5N    S: 32:59:59.5N   Res: 0:00:01
> |
>  |            E: 44:00:00.5E    W: 11:00:00.5W   Res: 0:00:01
> |
>  |   Range of data:    min = -9999  max = 6518
> |
>  |
> |
>  |   Data Description:
> |
>  |    generated by r.in.gdal
> |
>  |
> |
>  |   Comments:
> |
>  |    r.in.gdal input="/forest/ASTER-GDEM/Dem_lzw/mosaic.vrt" output="mosa\
> |
>  |    ic"
> |
>  |
> |
>
> +----------------------------------------------------------------------------+
>
> So I guess something is wrong with r.external..

Maybe it helps if you use the -r flag with r.external, otherwise the
range will not be correct.

Markus M