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soul45

CRISM TRR3 Map projection Algorithm

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Hello,

I am currently working with the CRISM Data in Matlab and when I load it, the data is always saved in a rectangular matrix. But since I need the original shape, I need to transform the cube data into it's original form. I have two screenshots how it should look like. I have also been able to read out the DDR file, but I can't find anything on the web on how to use that data. I would appreciate it if someone could help me further regarding this.

Screenshot_20180803_171122.png

Screenshot_20180803_171144.png

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Greetings: I am the Director of the PDS Geosciences Node and also a CRISM Team Member. I believe that the top image you show is one called sensor space, i.e., how the instrument acquires data row after row. The bottom one is map projected. The DDR file has planes that include the latitude and longitude in sensor space, corresponding to the pixel locations of the actual data. Are you trying to project the data to map form? If so would you be trying to do this in Matlab? ENVI can be used with the CRISM Analysis Tool (CAT) to do this for you. But if you need to use Matlab let me know in more detail what you are trying to do and we can help you get there.

Ray Arvidson

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@Ray Arvidson thank you for the replay.

I am aware of using ENVI and CAT so I can transform the cube data to the map projection. But I am trying to read the data into Matlab in combination with the MOLA data. But since the cube is distorted (stretched to fit in a cube), I can't align the cube data with the MOLA data. I have also been able to read the DDR file and I got a cube with 14 layers in the 3rd dimension. At layer 4 and 5 I have the latitude and longitude map, but I am not quite sure on how to read them, since the data oscillates a lot. Also to be noted, I am using these functions to read the cube and DDR data and at least the cube data look reasonable, but the DDR data look just uniformly gray with salt and pepper noise on them.

Thanks a lot for you help, since I am quite new in the field and I want to understand how to interpret the data I am getting.

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