d.rast.edit(1grass) GRASS GIS User's Manual d.rast.edit(1grass)
NAME
d.rast.edit - Edits cell values in a raster map.
KEYWORDS
display, editing, raster
SYNOPSIS
d.rast.edit
d.rast.edit --help
d.rast.edit input=name output=name [aspect=name] [width=integer]
[height=integer] [size=integer] [rows=integer] [cols=integer]
[--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
input=name [required]
Name of input raster map
output=name [required]
Name for output raster map
aspect=name
Name of input aspect raster map
width=integer
Width of display canvas
Default: 640
height=integer
Height of display canvas
Default: 480
size=integer
Minimum size of each cell
Default: 12
rows=integer
Maximum number of rows to load
Default: 100
cols=integer
Maximum number of columns to load
Default: 100
DESCRIPTION
The d.rast.edit program allows users to interactively edit cell cate-
gory values in a raster map layer displayed to the graphics monitor us-
ing a mouse cursor.
Overview window
An overview window shows the entire map with a red box showing the cur-
rent editing region. The edit window shows the cells within the se-
lected area. Click on a new spot on the overview window to move the
editing area.
Raster cell editing
Cell editing is done using the mouse cursor to indicate the cell(s) on
the displayed raster map that are to be edited.
To change the value of a cell put the new value to use in the "New
value" box at the bottom left of the edit window. A value of "*" indi-
cates a NULL value should be used.
Important: the new value in the "New value" box must be confirmed with
ENTER, otherwise it is not yet active.
Saving the edited map
To save the edited map, the "File" menu contains the entry Save. To
leave d.rast.edit, use Exit in the menu.
Map pan with arrow keys
The map can be shifted using the arrow keys on the keyboard.
NOTES
There is no "undo" command nor way to exit edit mode without saving
changes to the output map.
Any MASK in place will be respected when writing the new raster map
layer, including any edits to the MASKed areas.
Geographic Region Concerns
d.rast.edit reads the region definition for the raster map layer being
edited from its internal cell header file. The new, edited copy of the
raster layer will be created with the same resolution and region dimen-
sions.
The primary bane of the d.rast.edit program involves large map layers
with lots of rows and columns) and/or slow computers, since the program
must read and write raster map layers row by row for the full size of
the map layer as dictated by its region size and resolution. (The cur-
rent region settings of north, south, east, and west will not limit the
size of the edited copy of the map layer, since by use of the overview
selection these values may change several times during the editing ses-
sion).
EXAMPLE
Editing raster values in a LiDAR DEM, North Carolina sample data:
g.region raster=elev_lid792_1m -p
# pan to area of interest and edit raster cells (I used "102" as value to modifiy cells
# Use: File > Save to save
# then: File > Exit
d.rast.edit input=elev_lid792_1m output=elev_lid792_1m_modified
# comparison of raster statistics
# original stats, note the min value
r.univar -g elev_lid792_1m
# modified map stats, note the min value
r.univar -g elev_lid792_1m_modified
Figure: Editing of pixels in an elevation raster map using d.rast.edit
TODO
d.rast.edit should not create a new raster map layer if the user makes
no cell edits while running the program and leaving it without saving.
It would be nice to incorporate a scrollable version of d.legend (such
that one could see a label legend for files with many categories on a
standard size sub-frame). It would be even nicer to be able to select
the category values from a graphical legend when editing cell values
(thereby saving a trip to the text frame to type in the new value).
Perhaps method(s) for multiple or mass cell edits would be useful.
This could be done by providing modes in which the user may:
1 edit a block of cells to a given value by drawing a box;
2 be able to choose a given value which is automatically used as
the new value on each cell chosen until a different value is de-
sired.
There is no user-interrupt handling. This could leave files in .tmp or
(rarely) result in half-baked raster maps. The original file would
survive unscathed by an interrupt at most any point in execution. Be-
ware of exiting the program by means other than using exit on the Main
Menu.
SEE ALSO
d.rast.arrow, d.rast.num, wxGUI.rdigit
AUTHOR
Tcl/Tk (2007) and wxPython versions (2008): Glynn Clements
Replaces Xdriver version in C by Chris Rewerts, April 1991, Agricul-
tural Engineering, Purdue University
SOURCE CODE
Available at: d.rast.edit source code (history)
Accessed: unknown
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