1d.rast.edit(1) Grass User's Manual d.rast.edit(1)
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6 d.rast.edit
7
9 The d.rast.edit program allows users to interactively edit cell cate‐
10 gory values in a raster map layer displayed to the graphics monitor
11 using a mouse cursor. This program determines the name of the raster
12 map layer currently displayed in the active frame on the selected
13 graphics monitor (if none, program will abort). The user is then
14 prompted for the name of a new raster layer to be created in his
15 mapset. d.rast.edit does not modify the user's original raster map
16 layer.
17
19 d.rast.edit reads the region definition for the raster map layer being
20 edited from its cell header file. The new, edited copy of the raster
21 layer will be created with the same resolution and region dimensions.
22 If the current region resolution does not match the raster map layer's
23 resolution, the program will abort. The north, south, east, and west
24 geographic region settings of the current region can be set to any
25 view, as long as they fall within the boundaries of the raster map
26 layer described in its cell header. This is important, since the cur‐
27 rent view must be such that individual cell locations are easily visi‐
28 ble and sufficiently large on the graphics monitor to be pointed at
29 with the mouse cursor. Any mask in place will be ignored when writing
30 the new raster map layer.
31
33 Cell editing is done using a mouse cursor to choose menu selections and
34 indicate areas on the displayed raster map that are to be edited.
35 Selections available via the Main Menu and the subsequent functions or
37 sub-menus are described below: 1. Edit
38 invokes edit mode, during which no graphic menus are used, so that none
39 of the displayed map is hidden. At the start of the edit mode, a grid
40 is drawn over displayed cells to help distinguish cell boundaries.
41 Interaction with the program during edit mode is done by using the
42 three mouse buttons as follows: Left Button
43 what's here. Identify the category value of the cell under the mouse
44 cursor when the button is pressed. The category value of this cell is
45 printed in the text frame.
46 Middle Button
48 edit. The current category value of the cell under the mouse cursor is
49 iterated and a prompt for a new cell value appears on the textual com‐
50 mand frame. (Remember to move the mouse to the text frame). Enter a
51 new cell category value which is within the range of current category
52 values for the map layer. Note: the edited cell is displayed in the
53 color of the newly-assigned category value, but is hatched with lines
54 of the grid color to indicate it has been edited, since, if the value
55 of the cell is polled (before leaving edit mode), the old category
56 value will be reported.
57 Right Button
59 exit edit mode. Command is returned to the Main Menu on the graphics
60 monitor. If cell value changes were made during edit mode, they will
61 be saved upon exit.
62 2. Redraw
64 redisplays the raster map layer on the graphics monitor.
65 3. Zoom
67 calls the d.zoom
68 program, to allow changing the view of the raster layer. Zoom's
69 instructions will appear on the text command window. Interaction is
70 conducted using mouse keys.
71 4. Arrow
73 This function is available for users editing aspect maps. The
74 d.rast.arrow program is called, which draws arrows over the displayed
75 cells to indicate the downslope direction of the cell. After selecting
76 the arrow selection from the main menu, sub-menus will appear, allowing
77 input options to be set for the d.rast.arrow program. The first sub-
78 menu selects the type of aspect data displayed. (regular "GRASS" for‐
79 mat, as produced by r.slope.aspect ; a format prepared as input to the
80 "AGNPS" program; and a format prepared for the "ANSWERS" program. The
81 d.rast.arrow program can accept the name of a layer not drawn on the
82 display for use as input, and an option is given to input the name of
83 that layer, if desired. Otherwise, the currently displayed map layer
84 will be used. Next, the color options of d.rast.arrow may be set via
85 separate menus, or a choice for using default settings may be used.
86 5. Number
88 calls the d.rast.num program, which will print the cell category values
89 over the displayed cells on the graphic monitor.
90 6. Exit
92 quit the d.rast.edit program. If edits have been made, the new raster
93 map layer will be created. Support files are constructed. Category
94 labels and color maps (if any) are copied from the original layer.
95 d.rast.edit redisplays the original raster map file on the monitor as
96 it exits.
97
99 d.rast.edit will not create a new raster map layer if the user makes no
100 cell edits while running the program.
101 Be careful not to cover the graphics monitor window with another frame
103 during the editing process. In some cases, the redraw option will be
104 able to remove traces of other frames; otherwise, the graphics monitor
105 will not be refreshed until after d.rast.edit exits. Further note,
106 however, that this has only been tested on SUN workstations, using a
107 modified SUNVIEW graphics monitor driver.
108 The primary bane of the d.rast.edit program involves large map layers
110 (with lots of rows and columns) and/or slow computers, since the pro‐
111 gram must read and write raster map layers row by row for the full size
112 of the map layer as dictated by its region size and resolution. (The
113 current region settings of north, south, east, and west will not limit
114 the size of the edited copy of the map layer, since by use of the
115 d.zoom program, these values may change several times during the edit‐
116 ing session). Their effects could be lessened if the program were to
117 create a table of changes that it could incorporate into the new raster
118 file on a forked process started when the user exits, or otherwise
119 allow the user to issue a "save" command when he has made all desired
120 edits to the raster file. Currently, for instance, if the user needs
121 to use d.zoom to access a different area of the map, he must wait for
122 a read and write for each entrance and egress of the edit mode.
123 There is no "undo" command or way to exit edit mode without saving
125 changes.
126 It would be nice to incorporate a scrollable version of d.legend (such
128 that one could see a legend for files with many categories on a stan‐
129 dard size sub-frame). It would be even nicer to be able to select the
130 category values from a graphical legend when editing cell values
131 (thereby saving a trip to the text frame to type in the new value).
132 Perhaps method(s) for multiple or mass cell edits would be useful.
134 This could be done by providing modes in which the user may: 1) edit a
135 block of cells to a given value by drawing a box; 2) be able to choose
136 a given value which is automatically used as the new value on each cell
137 chosen until a different value is desired.
138 There is no interrupt handling. This could leave files in .tmp or
140 (rarely) result in half-baked raster files. The original file would
141 survive unscathed by an interrupt at most any point in execution, but
142 the graphics monitor may be left in an indeterminate state (try d.erase
143 or d.mon select=monitor_name to bring it back into shape). Beware of
144 exiting the program by means other than using exit on the Main Menu.
145 The program has no method to enter new values beyond the current range
147 of categories, but additional programming could make it so.
148
150 d.erase, d.frame, d.mon, d.rast, d.rast.arrow, d.rast.num, d.zoom,
151 g.region, r.slope.aspect
152
154 Chris Rewerts, Agricultural Engineering, Purdue University
155 Last changed: $Date: 2006/04/13 18:50:10 $
157GRASS 6.2.2 d.rast.edit(1)