The Grid Visualization Tool (GVT) is a computer program for displaying the path of a mobile robotic explorer (rover) on a terrain map. The GVT reads a map-data file in either portable graymap (PGM) or portable pixmap (PPM) format, representing a gray-scale or color map image, respectively.
The GVT also accepts input from path-planning and activity-planning software. From these inputs, the GVT generates a map overlaid with one or more rover path(s), waypoints, locations of targets to be explored, and/or target-status information (indicating success or failure in exploring each target). The display can also indicate different types of paths or path segments, such as the path actually traveled versus a planned path or the path traveled to the present position versus planned future movement along a path. The program provides for updating of the display in real time to facilitate visualization of progress. The size of the display and the map scale can be changed as desired by the user. The GVT was written in the C++ language using the Open Graphics Library (OpenGL) software. It has been compiled for both Sun Solaris and Linux operating systems.
This program was written by Caroline Chouinard, Forest Fisher, Tara Estlin, Daniel Gaines, and Steven Schaffer of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (818) 393-2827. Refer to NPO-40303.
This Brief includes a Technical Support Package (TSP).
Grid Visualization Tool
(reference NPO-40303) is currently available for download from the TSP library.
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Overview
The document provides a technical overview of NASA's Grid Visualization Tool (GVT), a graphics system designed to visualize rover traverses and activities. Developed by Caroline M. Chouinard at the Jet Propulsion Laboratory, the GVT enables users to display and track information related to terrain maps, planned rover paths, and changes in rover movement over time. This tool is essential for monitoring rover operations, allowing scientists to visualize the rover's targets, planned routes, and the status of various activities.
The GVT operates by reading in a terrain map, which can be in various formats, including binary PGM or PPM files. These maps can be hand-generated, artificially created, or captured from real cameras. The document emphasizes the importance of scaling the map appropriately to ensure that each pixel represents an equal distance in the real world. Accompanying the map, a configuration file is required to define the map's dimensions, while path planning output files are necessary to represent goals, waypoints, and path updates.
The GVT is designed to continuously update the display based on several events, such as changes to the map, new path information, window resizing, or changes in goal status. It is written in C++ and utilizes OpenGL libraries, requiring an average of 154MB of RAM. The tool has been compiled for both Sun Solaris and Linux operating systems.
The document also distinguishes between grid-based and vector-based terrain maps. Grid-based maps are represented as images where pixel values indicate free space or obstacles, while vector-based maps consist of vectors outlining obstacle boundaries. The GVT can handle grid-based maps efficiently, regardless of the number of obstacles, and can translate various file formats into a common standard.
In summary, the Grid Visualization Tool is a critical component for rover mission planning and execution, providing real-time visualization of terrain and rover activities. It enhances the ability of scientists and engineers to track rover progress, plan paths, and respond to changes in the environment, ultimately contributing to the success of robotic exploration missions. The document serves as a technical support package, offering insights into the tool's functionality and requirements for effective use.
