[GRASS-user] v.to.rast gives empty raster layer

[Hanlie Pretorius]

Hi Maris,

Thanks, your suggestion worked. With the region's resolution set to
5m, I got some output.


Regards
Hanlie

2011/5/2, Maris Nartiss <maris.gis at gmail.com>:
> g.region vect=contours_20m
>
> Also 20x20m cells wouldn't be too large?!?
>
> Maris.
>
>
> 2011/5/2, Hanlie Pretorius <hanlie.pretorius at gmail.com>:
>> Hi,
>>
>> I'm working in GRASS 6.4.1 on Windows XP.
>>
>> I want to use r.surf.contour to convert contour lines into a DEM.
>> However, I first need to convert my vector contour lines into raster
>> contour lines. My region is set to the contours_20m vector layer, with
>> a 20m resolution.
>>
>> v.to.rast --overwrite input=contours_20m output=contours_20m use=attr
>> column=HEIGHT
>> Loading data...
>> Reading features...
>> Writing raster map...
>> Converted areas: 0 of 0
>> Converted points/lines: 1593 of 1593
>> v.to.rast complete.
>>
>> r.info for the result is:
>>  | Layer:    contours_20m at CDNGI_DEM         Date: Mon May 02 14:18:00 2011
>>  | Mapset:   CDNGI_DEM                      Login of Creator: hanlie
>>  | Location: SA_Lo_29E
>>  | DataBase: F:\grassdata
>>  | Title:    Labels ( contours_20m at CDNGI_DEM )
>>  | Timestamp: none
>> |----------------------------------------------------------------------------
>>  |
>>  |   Type of Map:  raster               Number of Categories: 0
>>  |   Data Type:    DCELL
>>  |   Rows:         1772
>>  |   Columns:      1750
>>  |   Total Cells:  3101000
>>  |        Projection: Transverse Mercator
>>  |            N: -3121229.69982072    S: -3156672.30728643   Res:
>> 20.00147148
>>  |            E: -32474.90929218    W: -67483.27873573   Res: 20.00478254
>>  |   Range of data:    min = 1620  max = 2460
>>
>>  |   Data Source:
>>  |    Vector Map: contours_20m at CDNGI_DEM in mapset CDNGI_DEM
>>  |    Original scale from vector map: 1:1
>>  |
>>  |   Data Description:
>>  |    generated by v.to.rast
>>  |
>>  |   Comments:
>>  |    v.to.rast input="contours_20m at CDNGI_DEM" layer=1
>> type="point,line,ar\
>>  |    ea" output="contours_20m at CDNGI_DEM" use="attr" column="HEIGHT"
>> value\
>>  |    =1 rows=4096
>>
>> As you can see from the number of categories (0), there is no
>> information in this raster file.
>>
>> Can someone perhaps help me figure out why this happens?
>>
>> Thanks
>> Hanlie
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>