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Ray Arvidson

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  1. The attached paper will show you how the library was created. Ray Arvidson Viviano-Beck_et_al-2014-Journal_of_Geophysical_Research__Planets.pdf
  2. Rochdi: Glad to have helped you along. Stay safe and healthy. Ray Arvidson
  3. Rochdi: I am not sure what you are asking. CAT has spectral parameters for IR data. Use this function. I am not trying to be judgmental. However, I suggest that you need to read in detail the Viviano-Beck paper that was sent to you and that you become very familiar with CAT and its functions. Many of your queries would have been answered if you had done this homework in detail. Ray Arvidson
  4. Yes, although the Viviano-Beck paper that we sent to you shows which bands to use for her indices. If you use your own indices and select accordingly. Ray Arvidson
  5. It should be a monochrome image with bright areas indicative of a high value for the spectral parameter used, yes. Ray Arvidson
  6. Result is one monochrome image. Do your band math in sensor space, use CAT to flatten the result, and then project. Results will have to be your task. I do not know where the pyroxene is located. Ray Arvidson
  7. Your band math seems to be missing parentheses at the appropriate places. Please read the band math documentation for how to represent algebraic expressions. Ray Arvidson
  8. Yes, for each pixel in the scene R2210 means use the reflectance value at 2210 nm. ENVI's Band Math function will allow you to write an equation that when run produces the parameter map.The tool is in the ENVI5 series interfaces on the right hand side under Band Algebra. Also, the weightings a, b, etc. in the equations allow centering of the computation over the deepest part of the putative absorption feature, all relative to the wavelengths on the continuum on either side of the feature. Ray Arvidson
  9. Yes, your results are what they should be, so congratulations. Ray Arvidson
  10. I suggest you look at the range of values in your cube. If there are extremely high excursions because of noise, or in L data, use of 65535 to indicate non-data, the system will scale its output relative to the extreme values and results will be black. Remove these values before proceeding. Ray
  11. Hi: I am here to help. Tell me what you mean by a 3D cube? Do you want a data cube where planes are images and each pixel has a spectrum associated with it? So when you display the S and L combined cube and use the spectral plot as you move around the image in the display the spectrum for that location shows in a plot window. Is that what you want? Build 3D cube does not do that and only produces a nice perspective view of the cube with an image on the top and color-coded spectral values down the side. https://www.l3harrisgeospatial.com/docs/ImageCubes.html Ray Arvidson Ah, I se
  12. Hi: I am the PDS Geosciences Node Manager and CRISM Team Member. The browse products are byte images and just meant for visual examination. The summary products generated are floating point images that are based on the algorithms shown in the CRISM Software Specification Document. I suggest you read about these products in that document, which is posted on our web site. https://pds-geosciences.wustl.edu/mro/mro-m-crism-2-edr-v1/mrocr_0001/document/crism_dpsis.pdf Ray Arvidson
  13. Hi there: I will see if I can request from the code writers any documentation on the CIRRUS algorithm. I can tell you that there is no need to use any of the CIRRUS functions because the TRR3 I/F data cubes have been through a thorough denoising. I use CRISM data very day and have never used any of the CIRRUS functions. Also, the CRISM Team has generated, and we have posted on the Geosciences site, new versions of denoised cubes, TERs are in sensor space and MTRDRs are projected versions of the TERs. S and L cubes have been joined as one cube. See the CRISM SIS for an explanation of the p
  14. For the radiance data you must convert to IOF using the CAT tool before doing anything else. You need IOF products, i.e., radiance divided by the solar radiance for each band where the solar radiance used in the CAT conversion is for the heliocentric distance for Mars at the time of the observation. Ray
  15. First, do not give up on use of the IOF archive products. The artifacts mentioned in the Leask paper are associated with sharp albedo boundaries. Second, you need to turn the radiance into IOF files in CAT by using the "Radiance to IoF" function. Then you can do volcano scans and other processing steps. This will just produce noisier results than using the archived IOF files. I suggest do your work on archive and radiance to IoF files and compare results. Ray Arvidson
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