[GRASS-user] Re: TIN (Linear interpolation) from points

[Daniel Lee]

Hi there,

How are your points spatially distributed? It could that 1) the region
you're working with doesn't contain all points or 2) the resolution is so
low that the three points are aggregated to one point.

My suggestion would be to do g.region vect=gfa_niep_work to match the
region spatially to your vector map and then to set the resolution with
g.region res=X to something that you know will place each point in a
discrete pixel. Hope that helps!

Best,
Daniel

--

B.Sc. Daniel Lee
Geschäftsführung für Forschung und Entwicklung
ISIS - International Solar Information Solutions GbR
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Remote Sensing und dem GIS-Lab Marburg.




Am 22. März 2012 11:59 schrieb TheGeographer <dalura86 at googlemail.com>:

> Hi community,
>
> I'm trying to convert my 3 vector points to raster points. The aim is to
> use
> this raster points as input for r.surf.nnbathy.
>
> I created a region with following command:
> g.region --verbose vect=gfa_niep_work at PERMANENT nsres=1 ewres=1
>
> This is the output of the region:
>
> projection: 99 (Transverse Mercator)
> zone:       0
> datum:      potsdam
> ellipsoid:  bessel
> north:      5699460
> south:      5698740
> west:       3328920
> east:       3329940
> nsres:      1
> ewres:      1
> rows:       720
> cols:       1020
> cells:      734400
>
>
> In the next step I used v.to.rast with following commands:
>
> v.to.rast --overwrite --verbose input=gfa_niep_work at PERMANENT type=point
> output=gfa_niep_rast use=attr column=werte
>
> The metadata are these:
>
>
> +----------------------------------------------------------------------------+
>  | Layer:    gfa_niep_rast at PERMANENT        Date: Thu Mar 22 11:49:26 2012
> |
>  | Mapset:   PERMANENT                      Login of Creator: danny
> |
>  | Location: Test
> |
>  | DataBase: /home/danny/GIS
> |
>  | Title:    Labels ( gfa_niep_rast at PERMANENT )
> |
>  | Timestamp: none
> |
>
>
> |----------------------------------------------------------------------------|
>  |
> |
>  |   Type of Map:  raster               Number of Categories: 0
> |
>  |   Data Type:    DCELL
> |
>  |   Rows:         720
> |
>  |   Columns:      1020
> |
>  |   Total Cells:  734400
> |
>  |        Projection: Transverse Mercator
> |
>  |            N:    5699460    S:    5698740   Res:     1
> |
>  |            E:    3329940    W:    3328920   Res:     1
> |
>  |   Range of data:    min = 5.89  max = 5.89
> |
>  |
> |
>  |   Data Source:
> |
>  |    Vector Map: gfa_niep_work at PERMANENT in mapset PERMANENT
> |
>  |    Original scale from vector map: 1:1
> |
>  |
> |
>  |   Data Description:
> |
>  |    generated by v.to.rast
> |
>  |
> |
>  |   Comments:
> |
>  |    v.to.rast input="gfa_niep_work at PERMANENT" layer=1 type="point"
> outpu\
> |
>  |    t="gfa_niep_rast at PERMANENT" use="attr" column="werte" value=1
> rows=4\
> |
>  |    096
> |
>  |
> |
>
>
> +----------------------------------------------------------------------------+
>
> My problem is now that i get only 1 raster point with the value 5.89
> instead
> of 3 points.
> The correct range of the values should be min: 1.853 max: 5.89
>
> What did i wrong?
>
> Cheers
>
> --
> View this message in context:
> http://osgeo-org.1560.n6.nabble.com/TIN-Linear-interpolation-from-points-tp4627723p4644182.html
> Sent from the Grass - Users mailing list archive at Nabble.com.
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