Jump to content
PDS Geosciences Node Community


  • Content Count

  • Joined

  • Last visited

About Allendej

  • Rank

Recent Profile Visitors

1605 profile views
  1. I wonder if anyone would have a good book recommendation for getting stuck into ENVI+IDL coding with a focus on this type of data? Has anyone self taught with a particularly useful book?
  2. Thanks so much Frank for helping me find a way around this problem. I have now avoided calling select_summary_params entirely by taking the subscripts of the basic parameters from lvl (which just separated basic and advanced): selected_params=where(lvl eq 1, lvlsel) Elyse
  3. Hello, This is largely an IDL question concerning the new release of 2014 CRISM summary parameters in the CAT v7.3.1, so I'm not sure if it's appropriate here. I am working with: CAT_ENVI/save_add/CAT_Programs/Supplementals/select_summary_parameters.pro CAT_ENVI/save_add/CAT_Programs/Event_Handlers/mro_crism_summary_params_2014_event.pro Is there a way to bypass the control widget in 'select_summary_params.pro' and simply generate the default selections (basic products) without waiting for "OK" to be pressed? I want to link several CAT pre-processing steps together and
  4. Hello, When using the CIRRUS corrections within CRISM CAT I obtain an error - part of which is "no good data found". I know that CIRRUS corrections are generally unnecessary with TRR3 data, but the extra pre-processing really helps further on in my analysis. The destriping step is performed correctly, and I obtain an output image, so data exists. I have read the help file and taken a look at the .pro files for these corrections so that I can see what is going on, and varied my input parameters (spatial/spectral kernel size - yet always leaving spectral smoothing at 0) but to no avail. As I
  5. Hello, I notice that when I use the CAT 7.2.1 - Map Utilities - Project Single Cube Data tool, I obtain a different result than when I use the Build GLT tool in ENVI, with: X Geometry band = Band 5 of the associated DDR Y Geometry band = Band 4 of the associated DDR according to the instructions here on slide 23. http://crism.jhuapl.edu/data/CRISM_workshop_2009/docs/agenda/CRISM_Workshop_090322_Nili_Fossae_Walkthrough_FPS.pdf Looking at the IDL projection_event.pro, I see that the lat and lon keywords are defined as follows: ; Pull some planes from the geofile lat
  6. Hello, This is a very simple question, but I'm having trouble finding any information about this. Am I able to download the CRISM spectral library in order to perform spectral matching for spectra I have no prior knowledge about? I see that crism library data can be downloaded as a zip or tar file, but I am not sure how to handle the .tab files so that ENVI can see them as a library.
  7. Ah I see. Thank you. One more question, relating to TRDRs - do you know the approximate number of images that have been studied so far, or perhaps how many images are available? I know that Carter et al. (2014) submitted an abstract to the LPSC this year in which they conducted a survey of 2900 images (http://www.hou.usra.edu/meetings/lpsc2014/pdf/2364.pdf), and I wondered why this number was chosen as I read elsewhere that about 10000 images were taken in MROs PSP.
  8. Hello, I have just downloaded t0902_mrrsu_05s138_0256_1.img covering Gale crater, and just have some general questions: - Is the coverage for all mrrsu* products typically about 40% of a tile? I wasn't expecting such a large amount of missing data. - Is there any reason why each image strip seems to be individually normalised, but only in some products? For example, the IRAC product seems to have consistent values across the mosaic (I can clearly see the crater from the image), however, other products (mainly single band images, eg R440) appear to have each image strip with different
  9. Hello, I'm trying to locate mineral clusters in CRISM I/F data using a Self-Organizing Map, but ultimately, even though I normalize the data prior to running a SOM my output clusters correspond with bright and dark areas. I am working with GRASS and R, so here are my processing steps: - import CRISM data into R, each pixel contains a vector of 254 values corresponding to the I/F values in the first 254 image bands. I am now working with a matrix, of n rows (number of pixels in image) by 254. This CRISM data has previously been though the CAT pre-preprocessing pipeline.
  10. Hi Frank, Thanks very much for your reply. I know there is a list of detection thresholds for the OMEGA parameters in Poulet et al. (2007): 'Martian Surface Mineralogy from OMEGA/Mex', but I was wondering if there was such a list available for CRISM too? I know their formula are in Pelkey et al. (2007): 'CRISM Multispectral Summary Products' but I'd like to threshold each summary product with a realistic detection value - or is ~0.05/~0.1 applicable to most of the parameters?
  11. Hello, I've created some CRISM IR summary products using the CAT and am visualising them in combination with a HiRISE image. To highlight areas with the largest spectral response, in OLINDEX for example, I have read that typically stretching is performed using zero as the minimum realistic value and the 99th percentile as the maximum. The range of the OLINDEX parameter is very small: Minimum -0.107, Maximum: 0.084, so Adjusted Min: 0, Adjusted Max: 0.043. I was wondering what the typical expected values for these parameters are. What constitutes a significant response? For exampl
  • Create New...