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Jennifer Ward

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Blog Comments posted by Jennifer Ward

  1. User Shashwat Shukla

    Apr 12 2017 05:07 AM

    Hi June,
    I am working on Chandrayaan-1 M3 Data.
    Product ID: m3g20090205t071411_v03_rdn
    I am trying to geo reference the data as the method you suggested in your earlier
    comments, but I am unable to find what should I enter in Central Longitude option in
    customized map projection settings.
    I changed the projection type to Sinusoidal, Sphere Radius: 1737400 Easting and
    Northing as 0 and still couldnt find what to enter for 'Longitude for Central Meridian'. For
    now, I entered 74 as you mentioned.
    Then in edit map information, Datum chosen was D_Moon_2000 as you suggested. What
    should I enter in X, Y Coordinates ?
    Pixel Size I am using is 140 m as Spatial Resolution of M3 in Global Mode of OP1B data
    is 140 m/pixel. Is this right?
    Kindly guide me in the above!
    PS: I am not able find any detail in label file. The label file I am using is :
    Thanks a lot for your time!

    User June Wang

    Apr 12 2017 02:23 PM

    Hi Shashwat Shukla,
    It looks other users may have similar confusion as you when working with Chandrayaan-1
    M3 data in ENVI, so I put some tips here.
    A spectral radiance image cube label (*_L1B.LBL) is detached and points to the following
    L1B data products (Please see data product SIS file pages 20, 81 in 
    "¢ the single multi-band image (*_RDN.IMG) and its respective detached header file
    "¢ the pixel location data (*_LOC.IMG) and its respective detached header file
    "¢ the observation geometry data (*_OBS.IMG) and its respective detached header file
    "¢ the UTC timing data (*_TIM.TAB)
    Download all the *.loc, *.obs, *.rdn cubes together with the ENVI headers from ODE to
    your local drive. You can access the location and geometry information in the *.LOC
    and *.OBS files and relate it to the spectra of the *.RDN files using ENVI. Below link gives
    the instruction for basic viewing of an M3 *.img cube file using ENVI 4.3. Read those M3 
    cube file with high version of ENVI would have similar operations.
    note: In 'M3G20090205T071411_V03_LOC.HDR', it looks to me all the location data are
    in geographic lat and lons in degrees. There is no projection defined in the *.hdr. You can
    re-project the data to the Sinusoidal projection you defined. Central Meridian is the place
    where there is no distortion. Feel free to let me know if you need more help. 

    User Shashwat Shukla

    Apr 13 2017 12:55 AM

    Hi June,
    I had linked all the display to access the location and geometry information in the *.LOC
    and *.OBS files and relate it to the spectra of the *.RDN file.
    I had come across another method of building GLT files and geo referencing through
    The process I followed in that is by choosing X as Longitude and Y as Latitude, and then
    keeping the input projection as Arbitrary with Unknown Datum and output projection as
    you suggested , i.e., Sinusoidal with Sphere Radius 1737400 m , False Easting and False
    Northing as 0 and Central Meridian as 74 (Unsure whether right or not).
    As you said that Central Meridian is the place where there is no distortion, how to know
    the exact value of that. Because I am using the value which you suggested but it might
    vary with datasets (Not sure). Kindly tell whether 74 which I am using is right or there is
    some file in which it is written ?
    And one more doubt, how to reproject the data when the input file is not geo referenced ?
    PS: Since the *_RDN.IMG file is not geo referenced, so reprojecting it to Moon Sinusoidal
    projection can come up with error.
    Thanks a ton for your timely assistance.

    User June Wang

    Apr 13 2017 03:59 PM

    Hi Shashwat,
    It is not right to set 74 as the Central Meridian for the Sinusoidal projection. I didn't
    suggest this value before. I think it is just an example case that Jenn put together for users
    years ago. The Central Meridian of a Sinusoidal projection mainly depends on your own
    application. It is the place where you like it to have the least distortions.
    When you build the GLT in ENVI, you could choose Geographic Lat/Lon and
    D_moon_2000 for both the input and output as below figures.
    There are no data that could be free of errors. Uncertainties come from different sources
    such as instruments, measurements, processing methods and others. You could still reproject
    the data even it is not georeferenced, just with more uncertainties in the output.
    And the kind of projection depends on your own application and needs.
    Hope this will answer your questions. 

    User June Wang

    Apr 13 2017 04:02 PM

    Hi Shashwat,
    It seems I could not attach my screen shots in the above post. Feel free to let me know if
    you like me to send 'Geometry Projection Information' dialogue from ENVI to you by

    User Shashwat Shukla

    Apr 15 2017 04:57 AM

    Hi June,
    I did by assigning Geographic Lat/Long and D_moon_2000, but still I m not getting the
    right output.
    It would be better if you share your 'Geometry Projection Information' dialogue with me.
    My email: sshashwat93@gmail.com
    And I could also share my results with you.
    Thanks a ton June!

    User June Wang

    Apr 17 2017 06:51 AM

    Hi Shashwat,
    Please check your e-mail and let me know more details. 
  2. User Aeronstorm

    Dec 31 2016 05:00 AM

    I am trying to georeference, project and mosaic chandrayaan - 1, HYSI PDS 3 format files.
    It has a .qub and a label fle .lbl containing metadata. Do i need a separate grid file to
    georeference the raster ? What are the alternative softwares that can be used to finish
    the job ?
    It is an old post... But ,hey if anyone is hanging around .... help me.

    User June Wang

    Jan 03 2017 03:05 PM

    Hi Aeronstorm,
    I haven't worked with Chandrayaan HYSI data before, but I would recommend ENVI for
    your work. ENVI works with multi-spectral and hyper spectral PDS data. It also includes
    geometric correction/registration, raster re-projection, and mosaicking tools. As for the
    grid, you can use it or not, depending on your own application. Feel free to let me know if I
    am wrong or if you have any difficulties with ENVI. 

    User Aeronstorm

    Jan 03 2017 08:33 PM

    Thank you June. I did try the data with ENVI and it works fine. I need to know that if the
    polar stereo graphic projection technique mentioned above by you for LRO LOLA produts
    can be used with other Lunar satellite images.

    User June Wang

    Jan 04 2017 10:17 AM

    Hi Aeronstorm,
    Glad that ENVI works for you.
    The polar stereo graphic projection mentioned above should work with other Lunar data in
    ENVI. But please pay attention to below two points.
    1) Three map projection files related to the definition of datum, ellipse and map projections
    were saved under the default system folder where ENVI was first installed. It varies on
    different machines and different versions of ENVI being installed. E.g., for ENVI 5.3 in my
    machine, it was at "C:\Program Files\Exelis\ENVI53\classic\map_proj"
    2) you may need to change the parameters in the string in file map_proj.txt according to
    your own projection being used.
    "31, 1737400.0, 1737400.0, 90.000000, 0.000000, 0., 0., Moon North Polar
    Stereographic" is for Moon North Polar Stereographic projection
    "31, 1737400.0, 1737400.0, -90.000000, 0.000000, 0., 0., Moon South Polar
    Stereographic" is for Moon South Polar Stereographic projection
    In the string, 31 means Polar Stereographic projection in ENVI, 1737400.0 and 1737400.0
    are the a and b value of an ellipse, (90.000000, 0.000000) degrees in (lat, lon)
    corresponds to (0, 0)m in a projected map. You may modified those numbers to apply for
    different projections you would like to use in ENVI. And it is not limited to Moon.
    Hope this will answer your questions. 

    User Aeronstorm

    Jan 05 2017 02:16 AM

    Thanks June. Can i use the datum created as D_moon_2000 for other projections such as
    sinusoidal or should i create new datum file for other projections?

    User June Wang

    Jan 05 2017 09:42 PM

    In the string "D_Moon_2000, GCS_Moon_2000, 0, 0, 0", added to file datum.txt,
    'GCS_Moon_2000' is the name of an ellipse defined in file ellipse.txt
    If you use the same ellipsoid for other lunar projections, you can use the same lunar
    datum, otherwise, change the datum accordingly.

    User Aeronstorm

    Jan 06 2017 02:42 AM

    Thanks June. I am trying to use sinusoidal projection for my satellite image. Should i
    change the sphere radius equal to one mentioned on the ellipse.txt?

    User June Wang

    Jan 06 2017 11:26 AM

    Would you please give me more information about the satellite image you are working on?
    e.g., instrument, product type, product ID etc. And if you can post your current projection
    string for your data, I can take a look. Thanks.

    User Aeronstorm

    Jan 07 2017 01:38 AM

    Thanks June. I am working on Chandrayaan M3 data.
    Product ID- M3G20090421T082045_V03_RDN.
    map_proj.txt - 16, 1734000.0, 276.331769, 0.0, 0.0, moonsinusoidal

    User June Wang

    Jan 09 2017 10:26 AM

    Hi Aeronstorm,
    Is '1734000.0' a typo? The radius should be 1737400.0.
    I am not sure ENVI works with longitude in the range of [0, 360] or [-180, 180]. If
    276.331769 doesn't work for you, you can try to change it in the range of[-180, 180].
    Otherwise, your map projection string looks fine for me. And you can use the same datum
    as above mentioned. thanks
  3. User Shubhra mathur

    Aug 02 2014 02:26 AM

    I have prepared the mosaic of Lunar poles using the Mini-RF data of LSZ where the pixel
    resolution is 14.8 in ISIS software but when I visualize the data in ENVI i did not get the
    Latitude and Longitude values how do I can get this help me...

    User June Wang

    Aug 05 2014 10:19 AM

    Hi Shubhra mathur,
    I am not sure if you got my e-mail yesterday. Or maybe you have solved your problem.
    Would you please provide some more detail about your question if you need further help?
    1) Do you process the LRO mini-RF CDR data?
    2) Can you provide me the product_ID of the data you are processing, so I may reproduce
    your issue?
    3) What kind of ISIS output you used to be read in ENVI. Does that file have a ENVI
    header *.hdr?

    User Shubhra mathur

    Aug 06 2014 12:52 AM

    Dear Dr. June Wang,
    I have used the MAPCDR data of the Mini-RF and processed the data strip in the ISIS
    software using its different module and prepared the mosaics of the North pole. for
    example the product id of Mini-RF datastrip is lsb_00260_2cd_oiu_87s283_v1.img.
    When i visualize this strip in ENVI i did not get the latitude and longitute so i try to edit the
    map info of this file in the option of edit ENVI header but still i am not able to edit the map
    info of this file.
    Could you please help me in this regard.

    User June Wang

    Aug 07 2014 10:39 AM

    Hi Shubhra mathur,
    I also had hard time to change the map projection parameters in ENVI for this product. If
    you read Trent Thare's post at the below link, you will find ISIS is currently the only
    package working with Oblique Cylindrical projection data. You would need to reproject
    MAPCDR data to a different projection in ISIS for ENVI to understand the map projection.
    Then you can view it in ENVI in X,Y meters. Please let me know if you need further help.
  4. User pmishra
    Sep 20 2013 05:21 AM

    This was useful information. I am using LRO Lola's roughness data
    (LDRM_75N_240M.img). I was trying to open it in ENVI. However problem occurs in
    putting values for map projection. Which value should be given for latitude in true scale
    etc.? Could you please specify the values to be entered for this data type.
    It would be too helpful if you please tell me how to correctly open the LRO roughness data
    in ENVI.

    User June Wang

    Sep 25 2013 11:35 AM

    Update the Projection of LRO LOLA Products in ENVI 5.0 classic
    When working with the LRO LOLA Products, the JP2000 products are read in ESRI®
    ArcGIS with the correct map projection information, but ENVI cannot read the PDS IMG
    and JP2000 products correctly. The following steps will take LOLA GDR product:
    "LDRM_75N_240M.img" as an example, and show you how to fix this in ENVI 5.0 classic.
    1. Update the map projection files
    - ENVI includes three map projection files related to the definition of datum, ellipse
    and map projections. First check where ENVI points to the map projection files.
        - Select File > Preference, under User Defined Files Tab, find Map Projection
        - If the right blank is empty, ENVI will point to the map projection files saved
          under the default system folder where ENVI was first installed,
          e.g.,"C:\Program Files\Exelis\ENVI50\classic\map_proj\" for ENVI 5.0
          classic. This path may vary machine by machine. Otherwise, ENVI will point
          to the map projection files saved in the path as defined in the right blank.
    - Go to the folder where ENVI points to the map projection files. Backup the three
    files: "datum.txt", "ellipse.txt", and "map_proj.txt" before you make any changes.
    - Update file datum.txt
        - Open datum.txt
        - Add string "D_Moon_2000, GCS_Moon_2000, 0, 0, 0" to the end of the file
        - Save (If you have permission problem to save the file, please copy the file
          out to another folder. After changing, copy the saved file back to the original
          folder. If the permission is still denied, please give your system administrator
          to update the files.)
    - Update file ellipse.txt
        - Open ellipse.txt
        - Add string "GCS_Moon_2000, 1737400.0, 1737400.0" to the end of the file
        - Save (take care of the permission problem as above)
    - Update file map_proj.txt
        - Open map_proj.txt
        - Add string "31, 1737400.0, 1737400.0, 90.000000, 0.000000, 0., 0., Moon
          North Polar Stereographic" to the end of the file
        - Save (take care of the permission problem as above)
    - Restarting ENVI will update the changes in the map projections.
    2. Open the file in ENVI and edit the map information in the image header (take
    LDRM_75N_240M.IMG as an example)
    - Open LDRM_75N_240M.IMG in ENVI 5.0 classic
    - Follow the instructions in the original blog post above to edit the map information
        - Select File > Edit ENVI Header and select the image. Click OK.
        - From Edit Attributes, choose Map Info.
        - Click Change Proj.
        - In the pop-up Projection Selection window
          - Choose the projection "Moon North Polar Stereographic " that was
            defined in the first step
          - Choose D_Moon_2000 as the projection datum for the lunar product.
          - Use meter as units
          - Click OK
        - We go back to the Edit Map Information dialog. In this dialog, enter values
          from the label. For example, image coordinate x,y of 1905.6, 1905.6 (the
          projection center of this product) might be 0,0 with pixel size of 240 m/pixel.
          Click OK to save map information and OK to save header.
    - You can follow the same operations in step 2 to edit the map information of the
    JP2000 products, E.g., LDRM_75N_240M.JP2. This JP2000 product has the same
    product ID with LDRM_75N_240M.img. ENVI will treat them with the same *.hdr
    file. If both JP2 and IMG file are saved in the same folder, ENVI will have problem
    to open both files together. Either save them to different folders or change one of
    the file names will solve the conflict.

    User pmishra

    Sep 25 2013 11:59 PM

    Hi June,
    In step 2, of Edit Map information dialogue, I have put map coordinates as 90 N and 0 E.
    Is it correct?

    User pmishra

    Sep 26 2013 12:07 AM

    Hi June,
    Could you please tell the procedure to open and process this data in ArcGIS also.

    User June Wang

    Sep 26 2013 09:15 AM

    Hi Pooja,
    1) Regarding your question in step 2 -No. Since you already changed the map projection
    to the "Moon North Polar Stereographic", and the unit is meter. Even you put 90N and 0 E
    there, ENVI will interpolate this number as x = 0 m and y = 90m instead of degrees. Also it
    is kind of tricky. The pole actually corresponds to Lat 90, and Lon in [0, 360] or [-180, 180].
    2) Opening JP2000 map products in ArcGIS is straight forward. Using File->Open or
    directly dragging the file to the map window will work. ArcGIS will read those map
    projection parameters automatically.
    As for the PDS IMG data, ESRI mentioned in the following link that ArcGIS 10.1 supports
    some PDS 16-bit signed integer data, but still no multiband support.
    Trent at USGS also had a post about HiRISE PDS DEMs and ArcMap 10.x in the following
    My suggestion is if your PDS img is not recognized by ArcGIS, try to convert the PDS IMG
    to an ENVI format, then ArcGIS will read the data in ENVI format. Please let me know if
    you need more help. 
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