Sorry it's taken me so long to respond to you on this.
It's been quite a few years since I created the map data files from maps I downloaded from NASA, and I no longer have the program I wrote to create files.
I did a search for the surface and topographical rectangular maps that I used but have been unable to find them. I think the NASA web servers that they were on are no longer available.
The surface map was a 2880 x 1440 pixel flat map based on color-corrected Viking orbiter data. The topographical map was based on MGS Mola data, and was a little smaller so I had to expand the image a bit to be the same dimensions.
Rectangular globe maps are distorted along the vertical axis, so it's more horizontally spread out near the poles and is accurate at the equator. I didn't need all that distorted data, so wrote a simple program that would sample and store pixels from the map image; only a few pixels at the poles and all the pixels at the equator (sine curve).
The surface and topo files in map_data.jar consists of three files for each: *.sum, *.index and *.dat.
The *.sum files I don't really use any more, but contained the byte index of each line in the *.dat file.
The *.index files contain the number of pixel colors in each row. This is stored sequentally as integer values and read into an array used by the map generator.
The *.map files contain the pixel colors. It's stored sequentually with three bytes representing a color (each byte is red, green and blue components of the color, no alpha component stored).
The class that reads and caches this data in the programs is:
org.mars_sim.msp.ui.standard.tool.navigator.CannedMarsMap.java
The loadIndexData() method shows how to load the index data into an array.
The loadMapData() method shows how to load the map pixels into colors and stored in a list of integer arrays.
Anyway, let me know if you need anymore information on this. If I come across the map images we used in this, I'll be sure to let you know.
Couple questions about the Mars map data...
Is there a spec for interpreting the Mars map data? Also, what is the specific JPL link to the original Mars data?
Thanks,
Louis
Sorry it's taken me so long to respond to you on this.
It's been quite a few years since I created the map data files from maps I downloaded from NASA, and I no longer have the program I wrote to create files.
I did a search for the surface and topographical rectangular maps that I used but have been unable to find them. I think the NASA web servers that they were on are no longer available.
The surface map was a 2880 x 1440 pixel flat map based on color-corrected Viking orbiter data. The topographical map was based on MGS Mola data, and was a little smaller so I had to expand the image a bit to be the same dimensions.
Rectangular globe maps are distorted along the vertical axis, so it's more horizontally spread out near the poles and is accurate at the equator. I didn't need all that distorted data, so wrote a simple program that would sample and store pixels from the map image; only a few pixels at the poles and all the pixels at the equator (sine curve).
The surface and topo files in map_data.jar consists of three files for each: *.sum, *.index and *.dat.
The *.sum files I don't really use any more, but contained the byte index of each line in the *.dat file.
The *.index files contain the number of pixel colors in each row. This is stored sequentally as integer values and read into an array used by the map generator.
The *.map files contain the pixel colors. It's stored sequentually with three bytes representing a color (each byte is red, green and blue components of the color, no alpha component stored).
The class that reads and caches this data in the programs is:
org.mars_sim.msp.ui.standard.tool.navigator.CannedMarsMap.java
The loadIndexData() method shows how to load the index data into an array.
The loadMapData() method shows how to load the map pixels into colors and stored in a list of integer arrays.
Anyway, let me know if you need anymore information on this. If I come across the map images we used in this, I'll be sure to let you know.
Thanks,
Scott Davis
Mars Simulation Project
http://mars-sim.sourceforge.net
scud1@users.sourceforge.net