DESCRIPTION

Overview

• The Layer Manager includes map layer management, integrated command-line prompt, and command output window tab.
• The Map Display Window integrates basic tools for zooming, panning, data querying, and map elements (north arrows, barscale, etc.). Each display window is associated with its own set of map layers in the layer manager. The user may start multiple map displays during a session. The map layers for each display are grouped under different tabs in the Layer Manager.
• Module dialogs enable running GRASS modules that can be searched and launched via Tools tab.

Layer Manager

Figure: Layer Manager screenshot on Ubuntu

The top left button of the toolbar opens a new Map Display Window. Each map display has a unique set of layers to display and region settings. Other toolbar buttons add layers of different types for display in the selected map display window. There are additional buttons for saving or opening workspace file, and others.

Map layers are listed in the window frame below the toolbar. Layers can include raster and vector maps, vector labels, and commands (where any GRASS command can be written). Layers are displayed as arranged in the layer tree: the bottom layer is displayed first and the top layer is displayed last, as if the layers were a series of stacked overlays.

The check box to the left of each layer makes it active or inactive for display. Only active layers are displayed/redisplayed when the display button is pressed. Layers can be organized into groups; entire groups can be activated or deactivated for display. Layer tree composition can be saved to a workspace file and opened in subsequent sessions, restoring all layers and their display options.

A right mouse click on a layer or left clicking the button to the right of the layer opens a dropdown menu with options to remove or rename the layer (not the actual map), change its display properties (d.rast and d.vect options such as color, symbol, etc.), show its metadata (r.info, v.info) or attributes, if applicable.

A left mouse double click on a layer opens GUI for its display options These options are those for the d.* command for each layer type (d.rast, d.vect, or d.grid, for example).

Layer Manager Toolbar

  Start new map display

Opens a new map display and creates empty layer tree tab in Layer Manager.

  Create new workspace

Removes all layers from the layer tree and creates a new, empty tree where new layers can be added.

  Open existing workspace file

Opens an previously saved workspace file, containing a set of display layers and their option settings.

  Save current workspace to file

Saves current set of layers and their options to a workspace file.

  Load map layers into workspace

Loads selected raster or vector maps into current layer tree.

  Add raster map layer

Adds raster map to layer tree, see d.rast.

  Add various raster map layers (RGB, HIS, shaded relief...)

Opens a dropdown menu that allows user to select to:

  Add 3D raster map layer

Adds 3D raster map to layer tree.

  Add RGB raster layer

Combines and displays three raster maps defined as red, green, and blue channels to create an RGB color map, see d.rgb.

  Add HIS raster layer

Combines and displays two or three raster maps defined as hue, intensity, and (optionally) saturation channels to create a color map, see d.his.

  Add shaded relief raster map layer

Adds shaded relief raster map layer, see r.relief and d.shade.

  Add raster arrows layer

Adds map of raster cells with directional arrows drawn. Arrow direction and length are determined by separate aspect/directional map and (optional) slope/intensity map, see d.rast.arrow.

  Add raster numbers layer

Adds map of raster cells with numbers representing the cell values, see d.rast.num.

  Add vector map layer

Adds a vector map layer, see d.vect.

  Add various vector map layers (thematic, chart...)

Opens a dropdown menu that allows user to select to:

  Add thematic area (choropleth) map layer (for all vector types)

Adds layer for thematic display values from a numeric attribute column associated with a vector map. Options include: thematic display type (graduated colors or point sizes), methods for creating display intervals, SQL query of attribute column to limit vector objects to display, control of point icon types and sizes, control of thematic color schemes, creation of legend for thematic map, and saving the results of thematic mapping to a ps.map instructions file for later printing, see d.vect.thematic.

  Add thematic chart layer (for vector points)

Adds layer in which pie or bar charts can be automatically created at vector point locations. Charts display values from selected columns in the associated attribute table. Options include: chart type, layer and attributes to chart, chart colors, and chart size (fixed or based on attribute column), see d.vect.chart.

  Add group

Adds an empty group. Layers can then be added to the group.

  Add grid or vector labels overlay

Opens a dropdown menu that allows user to select to:

  Add overlay grids and lines

Adds layer to display regular grid (for all locations) see d.grid

  Add labels layer for vector objects (from existing labels file)

Add a layer of text from a labels file for vector objects created with the v.label module. A labels file can also be created with a text editor, see d.labels.

  Add geodesic line layer

Add layer to display geodesic line for latitude/longitude locations only, see d.geodesic

  Add rhumbline layer

Add layer to display rhumblines (for latitude/longitude locations only), see d.rhumbline.

  Add command layer

Adds a layer in which a GRASS GIS command or command list can be entered. For a command list use the semi-colon (";") symbol as a separator. For example:

d.rast soils;d.rast -o roads;d.vect streams col=blue

Note that when an option of the command contains spaces, you need to "escape" them with the backslash ('\') character, for example:

d.text text=Population\ density

  Delete selected layer

Removes selected map layer or map layer group from layer tree.

  Edit vector maps

Opens vector digitizer to allow editing selected vector map.

  Show attribute table

Opens attribute table manager for selected vector map.

  Import raster or vector data

  Import raster data

Import selected raster data into GRASS using r.in.gdal and load them into current layer tree.

  Link external raster data

Link selected external raster data as GRASS raster maps (using r.external) and load them into current layer tree.

  Set raster output format

Define external format for newly created raster maps (see r.external.out for details)

  Import vector data

Import selected vector data into GRASS using v.in.ogr and load them into current layer tree.

  Link external vector data

Link selected external vector data as GRASS vector maps (using v.external) and load them into current layer tree.

  Set vector output format

Define external format for newly created vector maps (see v.external.out for details)

  Raster Map Calculator

Launches Raster Calculator GUI front-end for r.mapcalc.

  Graphical Modeler

Launches graphical modeler to create models and run them.

  Georectifier Tool

Launches GCP Manager to create, edit, and manage Ground Control Points.

  Cartographic Composer

Launches Cartographic Composer to create interactively hardcopy map outputs.

  Show GUI settings

Opens dialog to change GUI settings.

  Show help

Opens GRASS manual.

Map Display Window

Figure: Map Display screenshot on Ubuntu

Each Map Display Window has a unique layer tree (in the layer manager) and geographic region setting. At the top of the window is a toolbar with buttons to manage the map in the display (render, erase, zoom and pan), for query and and analysis (distance measurement, profile, and histogram creation), to overlay map elements onto the display (scale, north arrow, legend, and custom text), and to export or print the display.

In the statusbar, the user can choose to display the geographic coordinates under the cursor, current geographical region extent, computational region (including graphical visualization in map display), map display geometry (number of rows, columns, resolution) and map scale. Checking the render button in the statusbar will cause the map display to update automatically any time a map is added to, removed from, or changed in its layer tree.

It is important to note that zooming in any display will have no effect on the 'computational region' setting (set with g.region). Only by selecting the 'Set current region to match display' item in the zoom menu (in the map display toolbar) will the current display extents be copied to the computational region extents.

Map Display Toolbar

  Re-render display

Re-renders all active map layers regardless of whether they have changed or not, see d.redraw.

  Erase display

Erases the currently selected map display to a white background, see d.erase.

  Pointer

Select arrow cursor for map display.

  Select features from vector map

Interactively select features from given vector map. Selection can be stored to a new vector map, see v.what and v.extract.

  Query raster/vector maps

Query selected raster, RGB raster (all three map channels will be queried), or vector map(s) using the mouse. Map(s) must be selected before query. Vector charts and thematic vector maps cannot be queried. The results of the query will be displayed in a dialog. See r.what, v.what.

  Pan

Interactive selection of a new center of view in the active display monitor. Drag the pan cursor while pressing the left mouse button to pan. Panning changes the location of the region displayed but not the size of the area displayed or the resolution. Panning does not affect the computational region for other GIS processes, see g.region.

  Zoom in

Interactive zooming with the mouse in the active display monitor. Drawing a box or just click with the mouse (left button) and zoom-in cursor causes the display to zoom in so that the area defined by the box fills the display. The map resolution is not changed. Clicking with the zoom-in cursor causes the display to zoom in by 30%, centered on the point where the mouse is clicked. Zooming resets the display region extents (both size and location of area displayed). It does not affect the computational region for other GIS processes, see g.region.

  Zoom out

Interactive zooming with the mouse in the active display monitor. Drawing a box or just click with the mouse (left button) and zoom-out cursor causes the display to zoom in so that the area displayed shrinks to fill the area defined by the box. The map resolution is not changed. Clicking with the zoom-out cursor causes the display to zoom out by 30%, centered on the point where the mouse is clicked. Zooming resets the display region extents (both size and location of area displayed). It does not affect the computational region for other GIS processes, see g.region.

  Zoom to selected map(s)

Set zoom extent based on selected raster or vector maps. Zooming resets the display region extents (both size and location of area displayed). It does not affect the computational region for other GIS processes, see g.region.

  Zoom to computational region extent

Set zoom extent based on the current computational region extent, see g.region.

  Return to previous zoom

Returns to the previous zoom extent. Up to 10 levels of zoom back are maintained, see g.region.

  Various zoom options

Opens a dropdown menu that allows user to:

• Zoom to default region
• Zoom to saved region. Zooms to previously saved named region.
• Set computational region extent from display. The computational region (the mapset's WIND file) is set to match the current display extent (does not change the resolution), see g.region.
• Set computational region extent interactively. The computational region is set simply by drawing a box with the left mouse button on Map Display.
• Set computational region from named region. This option doesn't affect display zoom.
• Save display geometry to named region
• Save computational region to named region

  Analyze menu

Opens a dropdown menu with:

  Measure distance

Interactive measurement of lengths defined with the mouse. The length of each segment and the cumulative length of all segments measuered is displayed in the command output window frame. Lengths are measured in the current measurement unit. Double-click to switch off measuring.

  Measure area

Interactive measurement of area defined with the mouse. Area is measured in the current measurement unit. Double-click to switch off measuring.

  Profile surface map

Interactively create profile of a raster map. Profile transect is drawn with the mouse in map display. The profile may be of the displayed map or a different map. Up to three maps can be profiled simultaneously.

  Create bivariate scatterplot of raster maps

Interactively create bivariate scatterplot of raster maps.

  Create histogram of raster map

Displays histogram of selected raster map or image in new window.

  Create histogram with d.histogram

Displays histogram of selected raster map or image in new window, see d.histogram.

  Vector network analysis tool

See tool's manual page.

  Add overlay

opens a dropdown menu that allows user to

  Add raster map legend

Adds layer to display with legend of selected raster map, see d.legend.

  Add scalebar

Adds layer to display a scalebar. Options include scalebar placement (using screen coordinates or a mouse), scalebar format, and scalebar colors, see d.barscale.

  Add north arrow

Adds layer to display a north arrow. Options include north arrow placement (using screen coordinates or a mouse), north arrow style and color, see d.northarrow.

  Add text layer

Adds layer to display a line of text using default GRASS font (selected with d.font). Options include: text placement (screen coordinates); and text size, bolding, and color, see d.text.

  Save display to graphic file

Save the visible image in map display to different raster graphic formats.

  Print map

Prints map on system native printer or PostScript device; saves visible map display (including PostScript text and labels) to PDF or EPS file.

Map display mode

Opens a dropdown menu for selecting different display mode

2D view

Normal GIS display. All active layers are composited and displayed in 2D mode.

3D view

Experimental replacement for NVIZ. Displays all active layers in 3D perspective using OpenGL. A new control panel opens to manage the 3D view. 3D view can be zoomed, panned, rotated, and tilted. The vertical exaggeration of rasters and 3D vectors can be set. Various color and lighten settings are possible. Not yet functional for Windows platforms

Vector digitizer

Puts display into vector digitizing mode and opens a new digitizing toolbar. The user can digitize a new vector map or edit an existing map.

Raster digitizer

Puts display into raster digitizing mode and opens a new digitizing toolbar. The user can digitize a new raster map or edit an existing map.

Keyboard short-cuts

Layer Manager

Ctrl+Tab

Switch 'Layers' and 'Console' tab

Ctrl+Q

Quit

Ctrl+R

Render map in all map displays

Ctrl+N

Create new workspace

Ctrl+O

Load workspace from file

Ctrl+S

Close workspace

Ctrl+Shift+L

Add multiple raster or vector map layers to current map display

Ctrl+Shift+R

Add raster map layer to current map display

Ctrl+Shift+V

Add vector map layer to current map display

Ctrl+W

Close current map display

Tab

Show command tooltips

Esc

Hide command tooltips

Ctrl+Space

Show auto-complete suggestions

Up/Down

List command history

Enter

Run command

Ctrl++

Increase font size (numerical keyboard plus key)

Ctrl+-

Decrease font size (numerical keyboard minus key)

Ctrl+mouse wheel

Increase or decrease font size

Map Display

F11

Fullscreen mode (toggle on/off)

Ctrl+W

Close map display

Ctrl+R

Render map (re-renders map)

F5

Render map (re-renders map)

Starting the GUI from command line

g.gui

g.gui -d wxpython

g.gui workspace=file.gxw

The user can also start GRASS from the shell command line with the wxGUI specifying the --gui switch:

grass --gui

The GUI can be quit by selecting the 'File > Quit GRASS GIS' menu item which gives options to close only GUI or to quit GRASS GIS entirely if GRASS GIS is running with a command line (a shell in a terminal application). Exiting the shell (typically by the exit command) ends the GRASS session including any running GUIs.

Background information

SEE ALSO

See also wxGUI wiki page (especially various video tutorials), and Quick wxGUI Tutorial.

AUTHORS