Table of Contents

Using Crusta

Crusta is currently in development. This page provides bare-bones instructions for early users. The instructions apply to using Crusta in desktop environment and assume that the software is started with the provided mouse.cfg configuration file (see below).

Crusta visualizes global terrain by rendering crusta globefiles. These files contain terrain data (DEM, imagery, etc.) that have been optimized for use with the visualization. Please see "Use Construo" for details on how to create globefiles. Example datasets can be downloaded from the Crusta Globefiles page.

Launching Crusta

Startup Configuration

Because Crusta is an application built using the Vrui framework it may run on a number of visualization environments from a laptop to an immersive CAVE. To facilitate desktop usage of the application it provides a startup configuration that bind Crusta's virtual tools to inputs on the keyboard with a mouse, and a command to automatically load this configuration (crusta-desktop).

The tool assignments are as follows:

crusta-desktop currently unavailable
Menu 1-key 1-key
Widget interaction left mouse button main trackpad button
Pan left mouse button main trackpad button
Rotate right mouse button z-key
Zoom scroll wheel Page-Up/Down swipe
Map Primary ctrl + left mouse button 2-key
Map Secondary ctrl + right mouse button 3-key

Map Primary is used to create and edit line mapping control points and Map Secondary to select and delete line mappings. See the Mapping section below for details.

Launching

1. Open a Terminal window.

2. cd into the folder from which you want to run crusta. All output generated by the program will be stored in that folder:

cd /path/to/crusta/output/folder

and then launch:

crusta-desktop [crusta globefiles]

You can launch Crusta with no default dataset and use the Crusta menu entry Load Data to select the globefiles to visualize from within the running application.

Examples:

crusta-desktop
crusta-desktop ~/Data/DEM.globeFile ~/Data/Color.globeFile

note: although the Color and DEM globefiles are folders that contain numerous files, only the base folder path should be used to specify the globefile.

The main menu of Crusta is brought up by pressing and holding the 1-key (as in the number one) on the keyboard. Entries of the menu are selected by moving the mouse pointer to the desired entry and then releasing the 1-key. Following features can be accessed through the menu:

Saving a viewpoint

Vrui easily lets you save and restore viewpoints within any program (3DVisualizer/LidarViewer/Crusta). Bring up the main menu (use the 1-key) and navigate to Vrui System –> View –> Save View and Vrui will export a file into the directory where you ran Crusta from. If it is your first saved viewpoint it will be called SavedViewpoint0001.view. You can rename this file, but be sure to leave the .view extension. To load this view back, from the main menu navigate to Vrui System –> View –> Load View and find the view you would like to load when the dialog box opens.

The Crusta desktop navigation binds the viewing manipulations to pivot around a point fixed on the surface of the globe. The left mouse button is used to pan: when held the motion of the mouse shifts the pivot point on the surface. The right mouse button is used to orient the view: when held the motion of the mouse rotates the view-point around the pivot point. Use the scroll-wheel to zoom in and out.

Mapping

In the desktop configuration (mouse.cfg), editing line art can be done as follows (WARNING: NO UNDO FUNCTIONALITY!):

The following applies to active polylines:

Saving mapping to various file formats:

Assigning attributes (this allows you to decorate lines in Arc with map symbols)

Applying color

A color map is generated for each scalar layer that is loaded for visualization. The colors generated for the scalar layers are composited using alpha-blending over the imagery layers.

Editing the color map

To edit the color map for a given scalar layer, open the Layer Settings from the main menu and select the desired scalar layer from the list. Then chose Palette Editor from the main menu to open the editor. The editor shows four workspaces from top to bottom: 1. the color map, where individual control points with color attributes can be set and modified; 2. the range editor that shows and controls how the color is mapped to the scalar domain; 3. information and color picking panel; 4. control point and palette controls.

Under the color map the minimum of the map interval is shown as the left-most value and the maximum as the right-most value. The middle value indicates the value at the center of the map interval. By default the color map is applied by repeating it over intervals which ranges are defined by the minimum and maximum value. This behavior can be changed to clamp the map only to the specified interval boundaries. To do so, open the Layer Settings from the main menu, select the desired scalar layer and click the Clamp button on that panel.

To manipulate the color of the map:

To manipulate the interval of the color map, use the sliders. Unlike a regular slider, where the position directly corresponds to a value, these sliders increment or decrement the manipulated value. The position of the slider off the center defines how fast to decrement (when dragging to the left) or increment (when dragging to the right). Release the slider nob to spring it back to the center position:

To save and load edited color maps:

Applying the color map using the terrain

In addition to the sliders in the Palette Editor, the range of the color map can be manipulated more interactively, by selecting locations on the terrain surface and assigning the scalar value at that location to the interval ends. This requires the use of the Crusta Surface Probe.

Before using the tool we must bind it to a button. Here we will use Alt+Left-Mouse-Button (AL). Press and hold AL to bring up the Vrui tool menu. Navigate to Crusta –> Surface Probe and release AL. This will pop up a small control window with the options “Dual” and “Single”. The “Dual” mode allows us to set the minimum and then the maximum of the interval whereas the “Single” mode shifts the interval.

Setting the minimum and the maximum directly on the terrain:

Sliding the range directly on the terrain:

Generating dynamic contour lines

Since the opacity of the applied color can be controlled, contour lines can be generated by carefully editing a color map of the DEM scalar layer such that it is mostly transparent but contains opaque pixels. For example setting the left and right control points to fully opaque black, then creating two new adjacent transparent control points will produce one line at the boundary of the range (the color map is repeated in periods corresponding to the elevation range). Now using the “Single” mode of the Surface Probe will dynamically move the contour line to the terrain location pointed to by the cursor.

Using the Vrui measurement tool

Use this tool to measure distances on the terrain. Before using the tool we have to bind it to a button, but we also have to make sure the mouse cursor is mapped to the surface of the terrain. For this purpose we will use 3-Button (3).

A menu should open that allows you to select the type of measurement and units. Select options you wish.

Use 3 to select locations on the surface of the terrain to measure. NOTE: after making your first measurement, zoom in and adjust the view (e.g., tilt to ~low-angle relative to the terrain surface) to make sure the nodes are actually plotting on (i.e., embedded within) the terrain surface. If not, the first step did not work.

To kill the measurement tool: move the cursor to the farthest point possible in the lower-left corner of the display and then press and release 3. When you move the cursor to the center of the screen and press 3, the Tool Menu should reappear. If not, kill was not successful.

How to load/process shapefiles into Crusta

Step 1. You will need:

Step 2. Open ArcScene

Step 3. Rename the output shapefile to Crusta_Polylines.shp Step 4. Start Crusta

To Print an Image

On Linux:

On Mac: