NAME
d.region.grid - Drapes a color raster over an shaded relief or aspect map.
KEYWORDS
display,
elevation,
relief,
hillshade,
visualization
SYNOPSIS
d.region.grid
d.region.grid --help
d.region.grid [-r] [region=name] [raster=name] [color=name] [width=float] [--help] [--verbose] [--quiet] [--ui]
Flags:
- -r
- Use the current computation region
- This will not work in cases when region is handled in a special way such as GUI
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- region=name
- Use an existing saved region
- raster=name
- Use a raster map
- color=name
- Color
- Grid color
- Default: gray
- width=float
- Grid line width
d.region.grid plots a grid defined by the computational region
or by a raster map.
The computational region can be the current computational region or a saved
computational region.
To compare how grids (resolutions) of two rasters align,
here a digital elevation model and a Landsat image,
you can zoom to an area of interest and show grids of both rasters.
First, zoom close enough that the raster cells become visible.
Here a small saved region is used and a negative value for
grow
causes
g.region to zoom-in even more:
g.region region=rural_1m grow=-250 -p
Start a monitor (skip this in the GUI):
d.mon start=cairo width=600 height=400 output=two_rasters.png
Optionally, show the digital elevation model and its shaded relief raster:
d.shade shade=elevation_shade color=elevation
Add grid for the elevation raster using a subtle color:
d.region.grid raster=elevation color="#9B520D"
Add grid for the Landsat raster using a high-contrast color:
d.region.grid raster=lsat7_2002_10 color=black
Figure: Grids of two rasters which are not aligned
If you are using
d.mon, you can stop the monitor using:
Let's say you want to render grid cells of a computational region
you plan to resample a raster map into.
First, set the computational region to the raster map, then start
the monitor (here we use file-based rendering in the command line
with the cairo driver), and finally, render the raster map:
g.region raster=elevation
d.mon start=cairo width=600 height=400 output=new_region_grid.png
d.rast map=elevation
Then change to the desired computational region, here the new region resolution
is set to 1000 meters (map units) and fitted into the current region extent
without modifying the 1000 meters value.
Now, you are ready to plot the grid of the current computational region:
Figure: Raster with resolution 10 meters and grid of a computational region
with resolution 1000 meters
Assuming you used
d.mon to start rendering as in the code above,
you can stop it using:
Displaying a saved computational region is extremely helpful in GUI,
were you save the current region first:
Then, you use
Add command layer to add the following command:
d.region.grid region=study_area
-
Use through the Add command layer option in the GUI.
-
In the GUI, it is currently not possible to directly draw the current region.
-
Generally, only the grid resolution is based on the selected region or raster,
with extent of the grid being limited only by what is being displayed
(this happens to be the current computational region when rendering
directly to files in command line).
g.region,
d.grid,
d.rast.num,
d.mon,
v.mkgrid
Vaclav Petras,
NCSU GeoForAll Lab
SOURCE CODE
Available at:
d.region.grid source code
(history)
Latest change: Wednesday Feb 02 21:46:15 2022 in commit: 2e3dcb5eafe36d640aa68585be0192f07ca1eabb
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GRASS Development Team,
GRASS GIS 8.4.1dev Reference Manual