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  1. Today
  2. eskandar mamaghani eskandar mamaghani joined the community
  3. June Wang
    October 19th, 2020 - SHARAD EDR and RDR data from ASI for MRO Release 54 loaded into ODE, also loaded missing SHARAD RDRs from previous MRO Release 24. - Loaded delayed SHARAD EDRs and RDRs from release 54 (Data coverage: November 10, 2019, through February 8, 2020) - Loaded SHARAD RDR (ASI) missing data from release 24 (Data coverage: June 3 through August 3, 2012)
  4. Yesterday
  5. Ray Arvidson
    Hi: I am a CRISM Team Member and PDS Geosciences Node Manager. So, you generated an IOF from radiance data. Then you did the "volcano scan" atmospheric correction, both using CAT? And you still have lots of noise in the 2 micrometer region, artifacts from trying to remove the CO2 triplet? Let me know and we can then go from there. Ray Arvidson
  6. ayushman
    Hi June, Have you received any update from the data provider regarding the line projection offset value ? Ayushman
  7. Last week
  8. Deepali Deepali joined the community
  9. Deepali
    Hello, I am a PhD scholar exploring water associated morphology and mineralogy of the Martian surface. I am working with L band of CRISM for detection of sulfates in my area. As Leask et al. (2018) have brought forward concerns with possible artifacts at 1.9 and 2.1 micron, I am having difficulty with confirming sulfates in my area. I have analysed radiance data for the same (as suggested by them). But my study area is dust covered so it has a lot of noise and spikes. I have tried ratioing radiance data but CO2 bands still persist. It does show absorption at those wavelength (similar to ratioed I/F) but CO2 absorption at 2.0 micron are big enough to destroy whole band shape. As of now, I am not sure if they are actual or spurious absorptions. It will be grateful if anyone can help me in confirming the results or suggest any method for resolving this issue. Thank you.
  10. Yuqi Qian Yuqi Qian joined the community
  11. Abinandhan Abinandhan joined the community
  12. Earlier
  13. ayushman
    Thanks June. I made changes as suggested and now am getting results for both lat and long max/min accurate upto 2-3 places after decimal. Is there a chance of further improvement in accuracy (say to 5-6 places after decimal) with updated line projection offset value provided by the data provider ?
  14. June Wang
    No-data area will not change the line and sample value of each pixel in the data. So the data will still start from (1,1) for the top-left corner. All you need is just ignore those no-data pixels in your calculation without changing the line and sample values.
  15. ayushman
    Hi June, Hope you are fine. Thanks for the suggestions. Using y = ( L0 – Line-1) * Scale Central Latitude = -70.8 degree Equation 20-15 for longitude calculation LINE_PROJECTION_OFFSET = 4476 Also, ignored the no data region for calculation (that is took sample = 1 for first data not in NODATA region) for each line. Moreover line = 1 is the line corresponding to the first line which has a pixel that is not in NODATA region. This has given good results for the latitude (obtained Lat range -71.4527 to -70.0472) but they still do not match exactly with expected latitude range of ( -70.06291 to -71. 47199). Longitude range obtained is 21.2084 to 25.46 (Against 21.38 to 26.011) . Maybe, once you get proper line projection offset value from the data provider, the result would match exactly. Ayushman
  16. June Wang started following Discrepancy in Line Projection offset value in PDS label for LRO NAC mosaic file
  17. June Wang
    One more finding is if using the function of “y = (1 - L0 - Line) * Scale” in line 128 of ‘DSMAP.CAT’ file, y value will always be negative with current label value input, which doesn’t match with the real y value in the data. It looks to me this equation could be changed to “y = ( L0 – Line-1) * Scale”. You can try LINE_PROJECTION_OFFSET = 4476. This value is just my guess, may not be correct. I have contacted with the data provider. I will post the final solution here when I hear anything back from the data provider’s.
  18. ayushman started following Discrepancy in Line Projection offset value in PDS label for LRO NAC mosaic file
  19. ayushman
    I have downloaded an LRO NAC mosaic of Vikram landing site (November image, 5m resolution) image from the following link http://wms.lroc.asu.edu/lroc/view_rdr_product/NAC_ROI_VIKRAM__LOC_P708S0237_5M I am trying to calculate and store the latitude and longitude coordinates for all the pixels in the mosaic into an array. As pointed in the 2nd point in the response below by Miss Wang, there appears to be a discrepancy in the LINE PROJECTION OFFSET value mentioned in the PDS label for the dataset. https://geoweb.rsl.wustl.edu/community/index.php?/topic/2804-details-needed-for-lroc-nac-mosaic-img-file/&do=findComment&comment=4621" "The LINE_PROJECTION_OFFSET value in the label doesn’t match with the value of CENTER_LATITUDE. Need to check with the data provider to see what the value used in their processing pipelines" Can you please let me know the correct LINE PROJECTION OFFSET value to be used for calculating Lat /Long values. Thanks Ayushman
  20. June Wang
    Hi Ayushman, Two things here. In your code, you looped around all the pixels. Please don’t include the nodata area in your calculation. The LINE_PROJECTION_OFFSET value in the label doesn’t match with the value of CENTER_LATITUDE. Need to check with the data provider to see what the value used in their processing pipelines. Thanks, June
  21. ayushman
    Hi June, Please find attached my MATLAB code . MATLAB's .m file extension is not supported and hence I am attaching a .txt version of the same. Kindly let me know if you need any more details. Thanks Ayushman mosaic_long_lat_store_code.txt
  22. June Wang started following ODE - The October 2020 PDS Release of MRO HiRISE data loaded into ODE
  23. June Wang
    October 9, 2020 – MRO HiRISE Updates - MRO HiRISE EDR, RDR, DTM and Anaglyph data products released through September 1, 2020 (Orbit 66099) See https://ode.rsl.wustl.edu/odeholdings/Mars_holdings.html
  24. June Wang
    Hi Ayushman, Attached is the screen capture of the LROC RDR (orange color, NAC_ROI_VIKRAM__LOC_P708S0237_5M.TIF) overlain on a WAC mosaic near the South Pole area together with its spatial reference information. The feature matches well. If everything is correct in the book, it looks to me equation 20-15 is a better fit for this case. Have you checked other parameters or steps in your calculation? If you can send me your code and your original value input for the calculation, I can take a further look. Thanks, June
  25. ayushman
    Hi June, Thanks a lot for resolving the queries. However, on going through the chapter on stereo graphic projections in the reference book “Snyder, J. P. (1987). Map Projections: A Working Manual", I have some more queries related to the value of Lat P and the expression to be used for Latitude/Longitude calculation. For LatP not equal to + or - 90 degrees , longitude is to be calculated as given in equation number => 20-15. However, an equation similar to the above equation can't even be found in the DSMAP.CAT file. Secondly equation 20-17 which is found in the DSMAP.CAT file to calculate the longitude can only be used for the case where LatP is -90 degrees Does the above suggest that for Polar Stereographic projection in moon's southern hemisphere we always have to take LatP = -90 degrees which was mentioned in the DSMAP.CAT file earlier and not the one to be used in the label file. I have tried with different combinations of Lat P and Lat/ Long expressions. The results obtained are attached in the excel file. I have not been able to replicate the results for Lat/Long ranges which are mentioned in the label file.Results are calculated using C = 2* ARCTAN[P/(2*Rp)] as pointed by you in the previous post. (Case 4) LatP = -90 degrees gives the best result. However the Latitude ranges are quite different from expected while Longitude range is much closer to the expected values but still different. Surprisingly (Case 2, LatP = -90 degrees) also gives decent result even though the expression used for calculating longitude is one which is reserved for case of LatP not equal to + or - 90 degrees. In any case LatP = -70.8 degrees (value mentioned in the label) doesn't give appropriate result. Kindly clarify. Please let me know of any discrepancies that may exist in the equations for calculating the Latitude and Longitude. Let me know if you need any other details from my side to resolve the issues. Thanks a lot for your patience. Ayushman results_calculated_using_different_LatP_and_Longitude_expressions.xlsx
  26. June Wang
    Hi Ayushman, Question 1-> It looks to me C = 2* ARCTAN[P/(2*Rp)] is correct, when compared this with the equation (21-15) in book page 159 of the book “Snyder, J. P. (1987). Map Projections: A Working Manual. U.S. Geological Survey Professional Paper 1395. Washington, DC: United States Government Printing Office.” Please let me know if this is not correct to your test. Question 2-> Please use the value in the attached label. The sentence written in the DSMAP.CAT is more like a general case. Thanks, June
  27. ayushman
    Thanks June for your reply. I downloaded the DSMAP.CAT file and also was able to access the label of the file. However, I still am not getting proper Latitude values and need certain clarifications with regard to the equations mentioned for obtaining Lat,Long coordinates. In polar stereo graphic projection section it is mentioned that P = SQRT(x^2 + y^2) ; C = 2 * ARCTAN(P / 2 * Rp) Just wanted to confirm if C = 2* ARCTAN[(P*Rp)/2] and not C = 2* ARCTAN[P/(2*Rp)] Secondly, it is mentioned that where LonP is the central longitude, LatP is the latitude of true scale and is always 90 or -90. However in the same section we have LatP defined to be equal to the CENTER_LATITUDE in the PDS Label. When I looked up the label, I found out that the CENTER_LATITUDE mentioned is not -90 but -70.8. Which of the 2 definitions should one take for calculation ?? Ayushman
  28. Rochdi
    Hello Feng, Thank you very much, I'll dive into it.
  29. Feng
    hi Rochdi, My suggestion is that you merge the S (VNIR) and L(IR) cubes into one and then slice them to what you want. The S cubes and L cubes have minor offsets. To merge them, you have to register one another. And then use attached IDL code to merge them. Following are detailed steps: 1, download the CTX covers the S/L cubes area in ODE (using Geotiff format CTX product) for example using crism trdr (frt0001176e_07) as example: first search frt0001176e_07 product then show result on map, you can see frt0001176e_07 area on the map; select CTX layer; on map display, draw a rectangle to cover this area using "Select Products with Rectangle" tool; download the CTX product in Geotiff format for exmaple (B07_012228_1427_XN_37S039W.tiff) 2, in CAT doing map projection for both S and L cubes 3. register map projected S and L cubes to the CTX product by using "Image Registration Workflow" Manually select tie points (I select 9 tie points ) between CTX and TRDR: 4, rename the attached SL_alignment_v5.txt to SL_alignment_v5.pro and open it in IDL, In IDL interface, click "Run', it will ask you select L cubes (results from step 3) , then select S cubes (results from step 3) and output the merged data. Now you have the data covers from 0.3646 to 4. You can select bands you need to export a subset data. SL_alignment_v5.txt
  30. ayushman
    Thanks June for your reply. I will check these links.
  31. June Wang
    Hi Ayushman, To get the lat&lon for each pixel of the LROC map projected RDRs, please read the ‘DSMAP.CAT’ at https://pds.lroc.asu.edu/data/LRO-L-LROC-5-RDR-V1.0/LROLRC_2001/CATALOG/, which gives the equations and steps on how to convert image array coordinates (Sample, Line) to map coordinates (x, y), and then from map coordinates (x, y) to planetocentric coordinates (Lat, Lon) for different kind of projections. All the parameters needed for the calculation could be find in the attached label of this product. Please let me know if you need more information. Thanks, June
  32. June Wang
    Hi Ayushman, Sorry, these are LROC NAC CDR data products. They are not map projected, but you can still use Arcmap and Gdal to read the data. I confused them with the LROC RDR data in your other post at https://geoweb.rsl.wustl.edu/community/index.php?/topic/2804-details-needed-for-lroc-nac-mosaic-img-file/&tab=comments#comment-4594. I will keep a post there on how to get the lat&lon for each pixel of the LROC map projected RDRs. In the index table under INDEX directory of the LROC CDR volumes, e.g., https://pds.lroc.asu.edu/data/LRO-L-LROC-3-CDR-V1.0/LROLRC_10**/INDEX/, you will find the lat&lon coordinates of the center point and 4 corner points. If you want to get the lat&lon for each pixel in the image, you will probably need to try the NAIF SPICE tools https://naif.jpl.nasa.gov/naif/toolkit.html or USGS ISIS https://isis.astrogeology.usgs.gov/index.html to see if they have function for this. Thanks, June
  33. Rochdi started following Complete Near-Infrared Spectrum
  34. Rochdi
    Hello, Expert. I have downloaded CRISM TRDR dataset concerning Ritchey crater. Then, I've implemented CAT extension in order to do some photometric and atmospheric corrections as well. As known, the TRDR dataset broken out into two ranges: VNIR (0.3646 - 1.0560) and includes 107 bands. IR (1.0014 - 4) and includes 438 bands. I want to split up those ranges to Visible, Near-infrared and Short-wave infrared into these following wevelength: Visible (400nm to 700nm) Near Infrared (700nm to 1300nm) Short-wave infrared (1300nm to 3000nm) It means if I split up CRISM VNIR range into visible and NIR spectrums, the visible spectrum starts from band7 to band53 (band7: 0.4036 - band53: 0.7032) and the rest of VNIR bands will be considered as NIR spectrum. However, the NIR spectrum extends till 1300nm and VNIR's last band wavelength is 1.0560, meaning that NIR needs some additional bands to be completed. My question: Can I take some bands from CRISM Infrared range to come up with a complete NIR spectrum? Look forward to your reply, Rochdi.
  35. June Wang started following Location coordinates needed for LRO NAC CDR images and ODE - New MEX OMEGA EDR Data Loaded into ODE
  36. June Wang
    October 6th, 2020 - New MEX OMEGA EDR Data Loaded into ODE - Updated MEX OMEGA EDR data products for extended mission 7 released through December 22nd, 2019 (Orbit 20196). See https://ode.rsl.wustl.edu/odeholdings/Mars_holdings.html
  37. ayushman
    Hi June, Thanks a lot for your reply. I am not familiar with ArcMap or any other GIS tool and am using MATLAB. I wanted to know if it's possible to store the actual Latitude and Longitude coordinates for each pixel in an array or an excel file using ArcMap or any other freely available GIS tool ? Ayushman
  38. June Wang
    Hi Ayushman, You can use gdal_translate command from gdal tool to translate the img data into a Geotiff, and use this Geotiff in any GIS tools. Arcmap can read the PDS IMG data directly with all its spatial reference information. The version I used here is an old one 10.2.2. Higher version should also work. June
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