Re: [GRASS-user] Elevation profile from intersecting shapefiles‏

[Micha Silver]

georgew wrote:

> Thanks Micha, here we go:
>
>     Micha Silver wrote:
>     How many shapefiles did you have in the GRASSDATA directory? ....
>
> provide the boundaries. Here is the result: r.info contours_rast 
> +----------------------------------------------------------------------------+ 
> | Layer: contours_rast Date: Thu Dec 4 08:50:19 2008 | | Mapset: 
> test02 Login of Creator: george | | Location: test02 | | DataBase: 
> /home/george/GRASSDATA | | Title: Labels ( contours_rast ) | | 
> Timestamp: none | 
> |----------------------------------------------------------------------------| 
> | | | Type of Map: raster Number of Categories: 0 | | Data Type: DCELL 
> | | Rows: 20 | | Columns: 20 | | Total Cells: 400 | | Projection: x,y 
> | | N: 6020724.5 S: 6013982.586 Res: 337.0957 | | E: 2481099.136 W: 
> 2467034.878 Res: 703.2129 | | Range of data: min = 520.000000 max = 
> 1840.000000 | | | | Data Source: | | Vector Map: contours at test02 in 
> mapset test02 | | Original scale from vector map: 1:1 | | | | Data 
> Description: | | generated by v.to.rast | | | | Comments: | | 
> v.to.rast input="contours at test02" output="contours_rast" use="attr" \ 
> | | type="line" layer=1 column="ELEVATION" value=1 rows=100000 | | | 
> +----------------------------------------------------------------------------+ 
> GRASS 6.3.0 (test02):~ > g.region -p projection: 0 (x,y) zone: 0 
> north: 6020724.5 south: 6013982.586 west: 2467034.878 east: 
> 2481099.136 nsres: 337.0957 ewres: 703.2129 rows: 20 cols: 20 cells: 
> 400 I hope all this helps. Your help so far has been invaluable, 
> thanks a lot. PS I tried to play around with resolution in the Region 
> dialog but the display never changed from the same chunky coloured 
> squares.
Here's What I can make out from the above:
The X-Y values are about 6,000,000 N and about 2,450,000 E, and the size 
of your region is about 14,000 X 6500. Let's *assume* these numbers are 
in meters (UTM projection??). But your resolution is set to 337 e-w and 
703 n-s, thus giving you a raster of 20X20 cells. That's certainly too 
coarse.
I'd suggest:
Blow away the rasters you made so far.
Set resolution to 10m. X 10m. with
g.region -s -p res=10
You should then see about 1400 columns by 650 rows =~ 910000 cells.
Now recreate those rasters. You should get better looking results.

-- 
Micha