[GRASSLIST:4353] s.surf.rst in a lat/long

[Maciek Sieczka]

the "slope" output of s.surf.rst in my wgs84 lat/long projection is wrong -
it's value range is min=89.721184 and max=89.999451 and the raster looks
rubbish

a similar approach in a tmerc projection gave a good result

my fault or some bug?

below is my "procedure" listed in detail

GRASS:~ > g.region -p
projection: 3 (Latitude-Longitude)
zone:       0
datum:      wgs84
ellipsoid:  wgs84
north:      50:45:57N
south:      50:42:12N
west:       15:40:54E
east:       15:46:57E
nsres:      0:00:03
ewres:      0:00:03
rows:       75
cols:       121

GRASS:~ > r.info N50E015.meters_filled

+---------------------------------------------------------------------------
-+
 | Layer:    N50E015.meters_filled          Date: Sun Sep  5 19:34:34 2004
|
 | Mapset:   dem                            Login of Creator: ziutek
|
 | Location: srtm
|
 | DataBase: /home/grassdata
|
 | Title:     ( N50E015.meters_filled )
|

|---------------------------------------------------------------------------
-|
 |
|
 |   Type of Map:  raster              Number of Categories: 1594
|
 |   Data Type:    FCELL
|
 |   Rows:         1201
|
 |   Columns:      1201
|
 |   Total Cells:  1442401
|
 |        Projection: Latitude-Longitude (zone 0)
|
 |            N: 51:00:01.5N    S: 49:59:58.5N   Res: 0:00:03
|
 |            E: 16:00:01.5E    W: 14:59:58.5E   Res: 0:00:03
|
 |   Range of data:    min =  178.000000 max = 1594.000000
|
 |
|
 |   Data Source:
|
 |
|
 |
|
 |
|
 |   Data Description:
|
 |    generated by r.patch
|
 |
|
 |                                      N50E015.meters_filled
|

+---------------------------------------------------------------------------
-+

GRASS:~ > r.to.sites -a input=N50E015.meters_filled output=dem_sites

GRASS:~ > s.info dem_sites

NDIM=2, RTYPE = -1, NSTR=0, NDEC=1
Total sites read: 9075
Total sites outside region: 0
dem_sites read.
----------------------------------------------------------

SITES FILENAME: dem_sites
--------------

Header Information:
------------------
        name          dem_sites
        description   r.to.sites -a input=N50E015.meters_filled
output=dem_sites                                label='No Label'
        format        ||%
        labels        Easting|Northing|%No Label

Number of DIMENSIONS:         2
--------------------
                 - - MIN - -     - - MAX - -
        dim  1     15.682083       15.782083    Easting
        dim  2     50.703750       50.765417    Northing

Type of CATEGORY information: NO CATEGORY
----------------------------

Number of DOUBLE attributes:  1
---------------------------
                 - - MIN - -     - - MAX - -
        dbl  1           682            1594    No Label

Number of STRING attributes:  0
---------------------------

TOTAL SITES COUNTED: 9075
----------------------------------------------------------

GRASS:~ > s.surf.rst input=dem_sites elev=dem_s.surf.rst
slope=dem_s.surf.rst_slp aspect=dem_s.surf.rst_asp

The number of points in sites file is 9075
The number of points outside of region 0
The number of points being used (after reduction) is 9075

Processing all selected output files
will require 84888 bytes of disk space for temp files

 100%
Percent complete: history initiated

GRASS:~ > r.info -r dem_s.surf.rst
min=682.395142
max=1593.271240
GRASS:~ > r.info -r dem_s.surf.rst_asp
min=0.549078
max=360.000000
GRASS:~ > r.info -r dem_s.surf.rst_slp
min=89.721184
max=89.999451