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

[Maris Nartiss]

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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