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Ralph Vidal

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Posts posted by Ralph Vidal

  1. hi Feng,

    I managed to correct the image as you explained.  But when I set the ignore value to  65535 it seems to keep a black stripe on one side that I cannot get rid of ( see attachments ) .  When I set the ignore value to 0,  the black stripe disappears but a white background appears.  There is some kind of white line around the picture too.  Do you maybe have any hints how to fix this ?






  2. Hi Feng,

    the geo-referencing  works now , I did the  images co-registering  as you explained.         The reprojected image is on the right place,   but it seems to  have an issue with the bands :    usually the false color RGB should be  bands 199, 354 and 419.    It shows strange results though ( image is red ,see pics )





  3. Hi Feng,

    thanks, I copied the files to the envi directory.  The error message is gone.      Anyway  the images still do not fit.

    1) CTX image:   

    Data http://murray-lab.caltech.edu/CTX/tiles/beta01/E-024/Murray-Lab_CTX-Mosaic_beta01_E-024_N20_data.zip
    Thumbnail        http://murray-lab.caltech.edu/CTX/tiles/beta01/E-024/Murray-Lab_CTX-Mosaic_beta01_E-024_N20_thumb.png


    2) CRISM image ( unprojected) :       frt0000a5aa_07_if166l_trr3

      http://themis-data.asu.edu/viewer/crism#P=FRT0000A5AA_07_IF166L_TRR3&T=2           ( all links  to download to ddr1 and img files on the page )


    Could the problem lie with the CTX image projection settings ?   





  4. Hi guys,

    I am using the CAT tool (latest version, 4/8/20)  to map project crism data,  I am not getting it right,   when I overlay the projected data on a CTX image  they do not quite fit.  When projecting  the crism tr3 image using CAT I get  error message shown in the first picture.

    The CAT instruction  at  https://astropedia.astrogeology.usgs.gov/download/Docs/PlanetaryDataWorkshop/Presentations2017/Monday/Humphreys/Morgan_CATupdates.pdf  tells that "


    Custom spheres, datum, and reference system definitions must be correctly installed

      Where do I get those definitions ?  Is there some .proj  file I have to put into the envi folder/ CAT folder ?

     The third picture shows the swipe made with a crism image overlain on the CTX image. Latitude seems to fit, longitude does not..






  5. Hi,

    I read in a CRISM doc that following:



    For most band depth and similar measures of absorption,

    • Zero is the minimum realistic value
    • The 99th percentile is typically a good maximum, although there is a empirically-determined “minimum maximum” that varies by parameter (e.g., 0.02 for D2300)

    Is there a table/document where such minimum/maximum  values can be found,  or is it image dependent and has to be found individually each time ?


  6. Hi Ray,

    yes, I got the CAT 7.4 from your website and installed it on ENVI 5.5.3 (  CAT does not appear on the menu when using envi classic, but it does not matter, as I am not using the classic gui ).    I am working with the S data because there is not enough L  data for this crater . Where L data is available , I will use it , otherwise I have use the S data .  It seems  the CAT tool  would only identify  ferric phases,  that is why I am trying to use ENVI's spectral angle mapping tool with the "rocks.sli"  library.

    The CRISM data files I get from  http://themis-data.asu.edu/     ( for example  http://themis-data.asu.edu/viewer/crism#P=FRT0000A5AA_07_IF166L_TRR3&T=2   ) - not the processed ones , but the ones with the link on the page ( ddr1, lbl, .img etc)



  7. Hi Ray,

    I finally managed to install  ENVI 5.5.3   on my computer.  As I wrote before , I  intend to use VNIR  crism data  with the  "rocks.sli" spectral  library.

    The first picture  ( crism VNIR  images overlain on CTX mosaic )  shows the area I want to process .   

    The second pic shows the results using SAM with Bandmax ( threshold of 0.05) applied to one  of  the VNIR images.   Does it make sense  ( using only VNIR  data with CRISM's "rocks.sli"  library ) ?   





  8. Hi,

    I am working with CRISM data on the McLaughlin Crater . I have downloaded following  IR dataset images

    • FRT0000CB488_07_IF166L_TRR3
    • FRT000139F7_07_IF166L_TRR3
    • FRT000247A0_07_IF166L_TRR3
    • HRS00006AC4_07_IF175L_TRR3
    • FRS00029E22_01_IF168L_TRR3
    • FRS0002B4DA_01_IF168L_TRR3
    • FRS0002C9DC_01_IF168L_TRR3
    • FRS0002DB50_01_IF168L_TRR3
    • FRS0002EF79_01_IF168L_TRR3
    • FRS0002FF3C_01_IF168L_TRR3
    • FRS0003134A_01_IF168L_TRR3
    • FRS00035729_01_IF168L_TRR3
    • FRS0003640C_01_IF168L_TRR3
    • FRS0003705A_01_IF168L_TRR3
    • FRT00009CAE_07_IF166L_TRR3
    • FRT0000A27C_07_IF166L_TRR3
    • FRT0000A5AA_07_IF166L_TRR3
    • FRT0000C42E_07_IF166L_TRR3
    • FRT0000C6AF_07_IF166L_TRR3

    as well as those VNIR images:

    • hsv0001bf65_01_if209s_trr3
    • hsv0001e87c_01_if209s_trr3
    • hsv0002e57c_01_if209s_trr3
    • hsv0003f9e0_01_if209s_trr3
    • hsv00043b25_07_if209s_trr3
    • hsv000293cf_01_if209s_trr3
    • hsv000412d4_03_if209s_trr3
    • hsv000478c2_03_if209s_trr3
    • hsv0002003a_01_if209s_trr3
    • hsv0002246d_03_if209s_trr3
    • hsv0003793e_01_if209s_trr3

    What would be the steps needed to process those images? As far as I understood I need to 
    1) Convert PDS to CAT ( is it needed ?  ) before loading image into Envi 
    1) ATM correction ( for VNIR images only photometric correction)
    2) CIRRUS ( despike + destripe)
    3) MRO CRISM remove stripes
    4) Flatten summary products ( what does it do ? is it necessary ? )
    5) Apply crism bad band list

    Are the above steps correct/enough/in the correct order , and is there a script ( IDL whatever ) to process thos images as a batch task ?

    I am doing a geological map of  the McLaughlin crater, using crism's "rock.sli" spectral library to map the geological units. Can this library be used with VNIR data, or only with IR data ?

    Ralph Vidal


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