GRIDVIEW: A COMPUTER PROGRAM FOR ANALYZING PLANETARY GRIDDED DATA

GRIDVIEW, a product of the Planetary Geodynamics Laboratory at NASA’s Goddard Space Flight Center, is a freely available Interactive Data language (IDL) computer program designed to aid researchers in their efforts to study, visualize, measure, and produce graphics of planetary gridded data. It is often used to study gridded topography products from instruments such as the Mars Orbiter Laser Altimeter (MOLA) or the Lunar Orbiter laser Altimeter (LOLA), but also can work well with other gridded data such as magnetic anomaly or gamma ray spectrometry. The application focuses on the visual display of data and includes tools for color adjustments as well as shaded relief that allow users to highlight and enhance areas of interest.

The program has many additional features, including measurement and plotting tools that have been successfully used for the mapping of craters and buried basins, as well as the measurement of distance, height, slope, area, and volume of various geomorphological features. For measurement accuracy, diameter constants for the Earth, Mars, and the Moon can be selected or the user can enter an arbitrary value to enable accurate measurement of data from nearly any sized circular body. Other program features include: latitude / longitude / data value tracking, global rotation and zooming, color stretching and contouring, profile plotting, image output, overlay of other data contours, image overlay, advanced area and volume calculation, and an interactive data fly through.

Users can load gridded data of various formats into GRIDVIEW, including the Experiment Gridded Data Records (EGDR) “.img” format that NASA’s Planetary Data System (PDS) uses to distribute MOLA topographic data, the IDL specific “.sav” format, and the Generic Mapping Tools NetCDF “.grd” format. Users can also load and view JPEG images such as the planetary images that can be created and downloaded from the USGS Map-a-Planet web site. GRIDVIEW is freely available for download at http://geodynamics.gsfc.nasa.gov/gridview and can run on any computer platform supported by IDL or the IDL Virtual Machine, available at http://www.exelisvis.com/.