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Susie Slavney

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  1. We were contacted by a user trying to read SHARAD EDR data with ReadPDS3 for IDL, but that tool does not read the bit fields and three-byte integers in the data product, and as it is a PDS3 tool it is not likely to be developed further. We suggested the following tools for working with SHARAD data. There was a SHARAD/MARSIS workshop at LPSC in 2014. Presentations are on the Geosciences Node’s web site at https://pds-geosciences.wustl.edu/workshops/sharadmarsis_Mar14.html. There's one by Than Putzig about the CO-SHARPS Processing Boutique, software that reads SHARAD products (not clear if he means EDRs, RDRs, or both) and creates radargrams, among other things. To get the software you have to request it from PSI at https://www.psi.edu/SHARAD. There are links to other software packages on the workshop page, but nothing specifically for reading EDRs. Most people prefer to use the RDRs. We have also posted an IDL script for generating browse images on the SHARAD page (https://pds-geosciences.wustl.edu/missions/mro/sharad.htm), as an example of how to read an RDR product. It might be possible to modify the code to read an EDR. Finally, we have some C# code to read the SHARAD EDRs, but the code does not read every field in the *.dat file. If you can let us know which fields you are interested in, we can try to modify the code to see if it works. The user replied, "for now that's fine for us skipping the unread fields. We could read the other data columns by slightly modifying the label/fmts of the SHARAD EDR. In case we would have to actually use those specific fields, I think that we could implement some specific reading routines, but it is some time to spend we don't really have for a non-critical purpose."
  2. The InSight SEIS data for Release 4, which had been delayed, are now available at the PDS Geosciences Node at https://pds-geosciences.wustl.edu/missions/insight/seis.htm.
  3. Data for InSight Release 4 are online at https://pds-geosciences.wustl.edu/missions/insight/index.htm. This includes data for RISE, RAD, and IDA. SEIS data have been delayed, but will be released by April 3.
  4. Some users of LRO Diviner data have asked why there are some data products with negative temperature values. For example: "I'm exploring the temperature data of the Diviner, I have downloaded TB (Brightness Temperature) data for 6,7,8, and 9 channels and I found negative values (in K) in a few of the images after conversion (TB= (DN * scaling factor) + Offset). This negative value is not possible in K, I'm unable to understand this." Answers from Diviner team members: "The shorter wavelength channels are noisy at low temperatures. Each channel has a minimum temperature below which it becomes noisy. These minimum temperature cutoffs go down with longer wavelength channels, so channels 8 and 9 are really the only ones that return useful data in the PSRs. When the channel gets below this minimum temperature, it starts returning negative radiance values. This would explain why channel 4 is giving you negative temperatures, while channel 9 does not. I've attached the Supporting Material from the Paige et al 2010 Science paper [see attachment Paige.SOM.pdf]. The table gives the minimum temperatures for the IR channels (3-9)." (Dr. Jean-Pierre Williams, UCLA, 2019-03-11) "The negative temperatures are actually "good" data. When the net signal at the detectors after calibration gets close to zero, Diviner records both small positive and small negative radiances. When the negative radiances are turned into brightness temperatures, they are reported as brightness temperatures. Zero-ing out the negative radiances would be completely inappropriate, because it is possible to pull signal out of the noise by averaging. You should see more negative temperatures in the shorter wavelength channels (3-6), as well as all channels in the coldest places near the poles. When the thermal emission from the moon is so small that there is no measurable signal, there's a 50% probability that a small negative signal will be measured. We convert these to brightness temperatures, and flag them as negative brightness temperatures, with the understanding that negative temperatures are not possible. In isolation, you can't convert negative temperatures into meaningful temperatures. What we generally do is pick a threshold below which all temperatures should be ignored. This will vary depending on which Diviner channel you are using." (Dr. David Paige, UCLA, 2020-03-24) Paige.SOM.pdf
  5. Many publishers of scientific research, including AGU, are now requiring authors to make their data available in a public repository as a condition of publication. (See AGU's policy here.) The Geosciences Node has been contacted by a few such authors asking whether the PDS will receive their data so that their articles can be published. In some cases the data set in question is a suitable candidate for a PDS archive, but usually it is not. If you are the author of an article for a journal that requires you to archive your data in a public repository, you may not wish to undertake the steps involved in submitting the data to the PDS, steps that include labeling, documenting, and possibly reformatting the data products. The effort involved may not be justified for a small, simple data set. In this case we recommend that you submit the data to one of the many available online data repositories, such as figshare (figshare.com) or Dataverse (dataverse.org). On the other hand, if you believe your data would be a useful addition to the PDS, and you are willing to put in the work and submit the data to a peer review, please send your request to geosci@wunder.wustl.edu.
  6. Data for InSight Release 2 are now available at https://pds-geosciences.wustl.edu/missions/insight/index.htm. This release covers data acquired between April 1 and June 30, 2019.
  7. Release 38 of Lunar Reconnaissance Orbiter data is now online at the Geosciences Node. This release includes new data acquired between December 15, 2018, and March 14, 2019, for most data sets. Data can be reached from the Geosciences Node LRO page. The Lunar Orbital Data Explorer allows searching and downloading of LRO data.
  8. I reported the broken links to the Astrogeology group at USGS-Flagstaff. They were fixed this morning. Thanks for letting us know.
  9. What is the problem you are having? Please be more specific.
  10. From www.mars.asu.edu/data you can download the TES mineral maps with the raw data in VICAR format. GDAL (https://www.gdal.org/) can read and export VICAR files. For example, these GDAL commands work on the VICAR files: gdalinfo TES_Glass_Clay_numeric.vic gdal_translate -of TES_Glass_Clay_numeric.vic TES_Glass_Clay_numeric_gdal.tif For another resource, there is MATLAB code to read VICAR files on Github at https://github.com/jnulzl/vicarRead.
  11. Data from Release 58 of the Mars Exploration Rover mission are now online at the PDS Geosciences Node. This release includes APXS, Atmospheric Opacity, Microscopic Imager, Navcam, Pancam, and RAT data from sols 5041 through 5130 for the Opportunity rover.
  12. Release 36 of Lunar Reconnaissance Orbiter data is now online at the Geosciences Node. This release includes new data acquired between June 15, 2018, and September 14, 2018, for most data sets. Data can be reached from the Geosciences Node LRO page. The Lunar Orbital Data Explorer allows searching and downloading of LRO data.
  13. Release 19 from the Mars Science Laboratory (Curiosity) mission includes new data for APXS, ChemCam, CheMin, DAN, and SAM. The data are online at pds-geosciences.wustl.edu/missions/msl.
  14. I believe the Matlab function "fread" would be the correct way to read a binary file, although I have no experience with Matlab. You will need to know the size and data type of the .img file, which are given in the corresponding label file (.lbl). In the label, look for the keywords LINES, LINE_SAMPLES, SAMPLE_BITS, and SAMPLE_TYPE. For example, for the product at your link above, the label shows LINES = 52224 LINE_SAMPLES = 5064 SAMPLE_BITS = 16 SAMPLE_TYPE = LSB_INTEGER (this means least significant byte first, or little-endian) The label also tells you that the file has 104449 records, each one 5064 bytes long, and the image data start at the second record. So you'll have to skip the first record. RECORD_BYTES = 5064 FILE_RECORDS = 104449 LABEL_RECORDS = 1 ^IMAGE = 2 I am guessing that the Matlab commands would be something like this: fid = fopen('m1185002263rc.img', 'r'); % Open the file to read status = fseek(fid, 5064, 'bof'); % Skip 5064 bytes from the beginning of the file a = fread(fid, [5064,52224], 'int16' 'ieee-le'); % Read in a 5064x52224 array of little-endian signed 16-bit integers Again, I am only guessing about the Matlab commands based on information I found online here. http://matlab.izmiran.ru/help/techdoc/ref/fread.html The image pixels are stored in the file in order from left to right, top to bottom. I understand the fread statement fills the array in column order. So you might have to transpose the array to get it to display correctly.
  15. Dear Shyam, To answer your questions: 1. The '.tif' files are reduced-resolution, compressed versions of the '.img' files. They are browse images; that is, they are intended to be used for a quick look at the data to help choose products of interest. They are not suitable for science analysis because the data have been compressed. The actual LROC image products are in the '.img' files, and yes, they can be very large. Each '.img' file has an embedded text header at the beginning of the file that has the metadata for the product, including the size, byte order, and bytes per pixel. You could use this information in Matlab to read in the image. 2. I think there should be a .tif file for every .img file. The one for M1185002263RC is online here: http://lroc.sese.asu.edu/data/LRO-L-LROC-3-CDR-V1.0/LROLRC_1023/EXTRAS/BROWSE/2015120/M1185002263RC_pyr.tif For more information about the image products, look here: - Lunar Orbital Data Explorer's User Manual page about LROC http://ode.rsl.wustl.edu/mars/pagehelp/quickstartguide/index.html?lroc.htm - LROC EDR/CDR Software Interface Specification http://lroc.sese.asu.edu/data/LRO-L-LROC-3-CDR-V1.0/LROLRC_1035/DOCUMENT/LROCSIS.PDF You might want to use the Lunaserv Global Explorer and the Quickmap 3D tools on the LROC web site, http://lroc.sese.asu.edu/archive. If you need more help, I will put you in contact with someone at the LROC Data Node. Regards, Susan
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