Hi,
I have several raster maps (aspect, slope, tand_curv etc.). I would like to combine these raster maps to one raster but without losing any information. As a result i would like to have one raster map with several attributes (aspect, slope, tang_curv etc.). And then I would like to check Pixel by Pixel
if slope = steep and aspect = North etc.
then
"Value of the checked pixel" + 10
else
....
Has anybody done this before? Is it possible to combine several raster maps without losing any information?
The GIS raster data model states that each cell contains
one and exactly one value.
That's why raster maps are also called "fields" in spatial
statistics. And it is why raster operations are so simple
and efficient.
ESRI ArcGIS 9.2 (not GRASS) has raster maps with multiple
attribute values attached to each cell -- but that's a
perversion of the entire concept in my opinion.
I am sure there must be a way of dividing your problem into smaller
steps such that you will be able to solve it with the standard
raster model.
Hi,
I have several raster maps (aspect, slope, tand_curv etc.). I would like
to combine these raster maps to one raster but without losing any
information. As a result i would like to have one raster map with several
attributes (aspect, slope, tang_curv etc.). And then I would like to check
Pixel by Pixel
if slope = steep and aspect = North etc.
then
"Value of the checked pixel" + 10
else
....
Has anybody done this before? Is it possible to combine several raster
maps without losing any information?
Hi, I have several raster maps (aspect, slope, tand_curv etc.). I would like to combine these raster maps to one raster but without losing any information. As a result i would like to have one raster map with several attributes (aspect, slope, tang_curv etc.). And then I would like to check Pixel by Pixel
if slope = steep and aspect = North etc.
then
"Value of the checked pixel" + 10
else
....
Has anybody done this before? Is it possible to combine several raster maps without losing any information?
Greets
Andreas
Thaw what you described has SpatialGridDataFrame in R. Simply you can import all raster data to one SGDataFrame and you can do there what you need.... It seems, becouse I can't understand for what you need 1 file instead of three or for and use mapcalc for that operation. Simply seems that mapalgebra (r.mapcalc) it is what you realy need
Andruit:
> I have several raster maps (aspect, slope, tand_curv etc.).
..
> And then I would like to check Pixel by Pixel
> if slope = steep and aspect = North etc.
> then
> "Value of the checked pixel" + 10
>
> else
>
> ....
>
> Has anybody done this before? Is it possible to combine several
> raster maps without losing any information?
sure, it is a basic thing for GRASS probably for 20 years. Combining the
maps into one first is a totally unnecessary step.
Jarosław Jasiewicz wrote:
Thaw what you described has SpatialGridDataFrame in R. Simply you can
import all raster data to one SGDataFrame and you can do there what you
need.... It seems, becouse I can't understand for what you need 1 file
instead of three or for and use mapcalc for that operation. Simply
seems that mapalgebra (r.mapcalc) it is what you realy need
e.g. r.mapcalc with the spearfish demo dataset:
g.region rast=elevation.dem
# GRASS usually measures aspect in degrees CCW from East
# logic: if(this is true, then do this, otherwise do this)
# "slope", "aspect", and "elevation.dem" are map names.
r.mapcalc "test = if(slope > 10 && (aspect >= 45 && aspect < 135),
elevation.dem, null())"
d.rast aspect
d.rast -o test
On 10/2/07 4:41 AM, "benjamin.ducke@ufg.uni-kiel.de"
<benjamin.ducke@ufg.uni-kiel.de> wrote:
The GIS raster data model states that each cell contains
one and exactly one value.
That's why raster maps are also called "fields" in spatial
statistics. And it is why raster operations are so simple
and efficient.
ESRI ArcGIS 9.2 (not GRASS) has raster maps with multiple
attribute values attached to each cell -- but that's a
perversion of the entire concept in my opinion.
I am sure there must be a way of dividing your problem into smaller
steps such that you will be able to solve it with the standard
raster model.
Hi,
I have several raster maps (aspect, slope, tand_curv etc.). I would like
to combine these raster maps to one raster but without losing any
information. As a result i would like to have one raster map with several
attributes (aspect, slope, tang_curv etc.). And then I would like to check
Pixel by Pixel
if slope = steep and aspect = North etc.
then
"Value of the checked pixel" + 10
__________________________________________
Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University