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Ray Arvidson

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About Ray Arvidson

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  1. Hi Maeve: Email me at arvidson@wustl.edu and I will send the Zoom invitation for Monday CDT 3pm. Ray
  2. Maeve: I am in the Central Daylight Savings time zone (CDT). What is your time zone? I am thinking about a one hour Zoom session this Friday at 3 PM CDT. Tell me which MTRDR you would like me to load up for the session on how to do some analyses using ENVI. Ray
  3. Hi Maeve: I would be happy to help out. In the past something like a one hour zoom session worked to get other users familiar enough with CRISM data to get them up and running on analysis. Let me know if this would be a good approach and when you might be available next week. Ray
  4. Maeve: You can load MTRDRs directly into ENVI without the need for the CAT extension. This is because these files come with an envi header. Let me know if this works for you. Ray Arvidson
  5. Maeve: You are downloading CAT from our Geosciences Node site? Try incorporating it into ENVI 5.5.3 or 5.6, not the Classic version. If you need help let me know. We can then go from there. Tryi using our PDS Mars Orbital Data Explorer to find and download some MTRDR files. I can help you get started on how to use the data once you get CAT working with ENVI. Ray Arvidson
  6. Hi Maeve: ENVI is the main way that researchers process CRISM data, including mapping mineral parameter maps. Do you have access to ENVI? And do you know which CRISM scenes you would like to use? I can tutor you through using ENVI and CRISM data, but first let me know if you have access to ENVI software. Ray Arvidson Geosciences Node Manager and CRISM Team Member.
  7. See attached paper, Section 5.3, for what we do for thresholds for parameter maps. Choosing a neutral spectrum is a case of trial and error. I do not do this, rather I just look at the volcano scanned spectra for features such as the 2.3 um metal-OH absorption. Ray Arvidson Viviano-Beck_et_al-2014-Journal_of_Geophysical_Research__Planets.pdf
  8. DISORT is a generally applicable radiative transfer program and is available over the internet. We use a front end that is Mars specific. It is incredibly complicated and not meant for distribution. May I suggest that unless you wish to do Hapke-related nonlinear modeling of mineral grain sizes and phases you just stick to what CAT offers. Except for our group very few researchers try and use DISORT in their CRISM data analysis. Ray Arvidson CRISM Team Member PDS Geosciences Node Manager
  9. The attached paper will show you how the library was created. Ray Arvidson Viviano-Beck_et_al-2014-Journal_of_Geophysical_Research__Planets.pdf
  10. Rochdi: Glad to have helped you along. Stay safe and healthy. Ray Arvidson
  11. 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
  12. 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
  13. It should be a monochrome image with bright areas indicative of a high value for the spectral parameter used, yes. Ray Arvidson
  14. 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
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