[GRASS-user] Re: Strategies for using v.surf.rst (getting rid of
those segmentation boxes)
Paulo Marcondes (Pmarc)
paulomarcondes at gmail.com
Mon Jun 9 15:39:19 EDT 2008
Jonathan Greenberg <greenberg <at> ucdavis.edu> writes:
>
> Grassers:
>
> I'm using v.surf.rst, and I'm wondering what the best strategies for
> getting rid of those rectangular segmentation boxes are, while also not
> having the high local peaks around lone sample points? Thanks!
Hi All,
I am having the same issue as Jonathan, I know it is being caused by lack of
data.
Original data is unretrievable, but I did digitalize in GRASS 6.2 from a
scanned paper map.
In the pics, you can see the vector lines in blue (v.digit'ized) and the
raster made with r.surf.rst
Those are isopach (thickness) and sand isolite (sand content [%]) maps. I
digitized the values x100 the original, because of some remark in the GRASS
book, but now I think it applied to r.surf.contour
Note that I don't _need_ to use r.surf.rst, but I _need_ a smooth raster.
Whatever method that is capable of that. Also, vector lines are the best _I_
could do, so no increase in resolution is possible, but alternate methods are
nice =]
In the meantime, I'll try Hamish's suggestion.
http://paulomarcondes.googlepages.com/isopaca.jpg
r.info for this raster:
+----------------------------------------------------------------------------+
| Layer: isopaca_sseqC.elev Date: Fri Jun 6 10:45:17 2008 |
| Mapset: PERMANENT Login of Creator: cmp9 |
| Location: Aratu_BC |
| DataBase: /u/cmp9/gisdata |
| Title: ( isopaca_sseqC.elev ) |
| timestamp: none |
|----------------------------------------------------------------------------|
| |
| Type of Map: raster Number of Categories: 255 |
| Data Type: FCELL |
| Rows: 1292 |
| Columns: 1166 |
| Total Cells: 1506472 |
| Projection: UTM (zone -24) |
| N: 7668884.01433 S: 7475133.68393 Res: 149.96155604 |
| E: 450329.267038 W: 275417.899494 Res: 150.00974918 |
| Range of data: min = -11.243400 max = 70065.601562 |
| |
| Data Source: |
| vector file isopaca_sseqC |
| |
| |
| Data Description: |
| generated by v.surf.rst |
| |
| Comments: |
| giventension=40.000000, smoothing=0.100000 |
| dnorm=23529.679966, dmin=100.000000, zmult=1.000000 |
| segmax=40, npmin=300, rmsdevi=22.054472 |
| zmin_data=0.000000, zmax_data=70000.000000 |
| zmin_int=-11.243400, zmax_int=70065.601691 |
| |
| v.surf.rst -t input="isopaca_sseqC" layer=1 zcolumn="isopaca" dmax=3\ |
| 50 dmin=100 elev="isopaca_sseqC.elev" slope="isopaca_sseqC.slope" as\ |
| pect="isopaca_sseqC.aspect" pcurv="isopaca_sseqC.curv" tcurv="isopac\ |
| a_sseqC.tancurv" mcurv="isopaca_sseqC.meancurv" maskmap="isopaca_mas\ |
| k" zmult=1 tension=40. segmax=40 npmin=300 |
| |
+----------------------------------------------------------------------------+
http://paulomarcondes.googlepages.com/isolita.jpg
r.info:
+----------------------------------------------------------------------------+
| Layer: isolita_sseqC.elev Date: Thu Jun 5 15:21:08 2008 |
| Mapset: PERMANENT Login of Creator: cmp9 |
| Location: Aratu_BC |
| DataBase: /u/cmp9/gisdata |
| Title: ( isolita_sseqC.elev ) |
| timestamp: none |
|----------------------------------------------------------------------------|
| |
| Type of Map: raster Number of Categories: 255 |
| Data Type: FCELL |
| Rows: 1292 |
| Columns: 1166 |
| Total Cells: 1506472 |
| Projection: UTM (zone -24) |
| N: 7668884.01433 S: 7475133.68393 Res: 149.96155604 |
| E: 450329.267038 W: 275417.899494 Res: 150.00974918 |
| Range of data: min = -93578.492188 max = 804178.500000 |
| |
| Data Source: |
| vector file isolita_sseqC |
| |
| |
| Data Description: |
| generated by v.surf.rst |
| |
| Comments: |
| tension=40.000000, smoothing=0.100000 |
| dnorm=33181.595517, dmin=100.000000, zmult=100.000000 |
| segmax=40, npmin=300, rmsdevi=4581.273762 |
| zmin_data=200000.000000, zmax_data=800000.000000 |
| zmin_int=-93578.488628, zmax_int=804178.527938 |
| |
| v.surf.rst input="isolita_sseqC" layer=1 zcolumn="isolita" dmax=350 \ |
| dmin=100 elev="isolita_sseqC.elev" slope="isolita_sseqC.slope" aspec\ |
| t="isolita_sseqC.aspect" pcurv="isolita_sseqC.curv" tcurv="isolita_s\ |
| seqC.tancurv" mcurv="isolita_sseqC.meancurv" maskmap="isolita_mask" \ |
| zmult=100 tension=40. segmax=40 npmin=300 treefile="isolita_quadtree\ |
| " overfile="isolita_windows" |
| |
+----------------------------------------------------------------------------+
Also:
GRASS 6.2.3 (Aratu_BC):~/gisdata/Aratu_BC/PERMANENT > g.region -p
projection: 1 (UTM)
zone: -24
datum: ** unknown (default: WGS84) **
ellipsoid: a=6378388 es=0.006722670022333321
north: 7668884.01433
south: 7475133.68393
west: 275417.899494
east: 450329.267038
nsres: 149.96155604
ewres: 150.00974918
rows: 1292
cols: 1166
cells: 1506472
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