Jump to content
PDS Geosciences Node Community

Georeferencing PDS images in ENVI


Subhabose
 Share

Recommended Posts

  • 5 months later...

Hi, good morning.
When working with PDS Europa or Io images of the Galileo SSI, how should I georeference my images? What projection should I use?
I was looking for the Dr. June Wang's Assigning Map Information to PDS Images in ENVI post for reference, but I was unable to find it.
Thanks in advance.


 

Link to comment
Share on other sites

Dear Dr. June.

Thank you very much for your quick answer.
I’ve been working the whole day on this little project and two situations have developed:

1.- I’ve read the post you provided (Thank you very much I also read Getting ENVI to read your PDS image correctly).
2.- I changed my subject of study and objective.
Now I'll be trying to estimate the age of Enceladus' northern pole with the Buffered Crater Counting Technique. I'll be doing it with the help of ArcGIS' add-ins CraterTools & CraterStats.
image.thumb.png.52c375136d6497ac5ab76ad9c99cab9b.png
This is the best image of the features I was able to find. I uploaded the .img and .lbl (in .txt format) in this post.

I am using T. Kneissl & G. Michael's Crater Size-Frequency Measurements on Linear Features - Buffered Crater Counting in ArcGIS and T. Kneissl et al. New Software Tool for Map-Projection Independent Crater Size-Frequency Determination in ArcGIS as reference.

And following the post you provided (thanks again), I really tried to create my own lunar projections in ENVI, but I was unable to do so. (I didn't find the buttons of the post's steps 3 to 9 in my ENVI software). And I really don't know why.
But I discovered how to do all that in ArcMap. And I even find out that ArcGIS has it's own set of projections and coordinate systems for most of the solar system bodies, Enceladus included.

.image.png.7b52c33fd7af53f0686d137f41a4d9ab.png

Sadly it was not a sinusoidal projection. So I had to create my own projection based upon the default one but with a sinusoidal projection for Enceladus.
However, I'm still wondering what to to with the pronounced curvature of my image.

I think I don't really need my image to be georeferenced for the ArcGIS' add-ins to work, but I would really like to know your opinion on what should do in this case.
Should I georeference my image?
Should I change it for one I can easily project in a custom made projection?
Should I try to orthorectificate it?
Or how should I justify the fact that I'm not georeferencing my image?

I include the PDS data & both papers.

Thank you very much in advance for you time.
Please stay safe and be careful.

Best regards!
Lex S.
 

N1584039961_2.txtN1584039961_2.IMG

T. Kneissl & G. Michael Crater Size-Frequency Measurements on Linear Features - Buffered Crater Counting in ArcGIS.pdf T. Kneissl et al. New Software Tool for Map-Projection Independent Crater Size-Frecuency Determination in ArcGIS.pdf

Link to comment
Share on other sites

Yes, ArcGIS has better projection engine defined. And ENVI used ArcGIS projection engine in its application. The steps 3-9 you mentioned are actually based on ENVI classic interface. That blog was written years ago. After that there are many new release of ENVI, and its current version is 5.6. I don’t know which version you are using now, probably something 5.4+. If you are using a newer version of ENVI interface, one way to add the spatial reference is to find “Edit ENVI Header” under “Raster Management” in the toolbox as shown below in the right. You can add spatial reference from there. Instead of adding something for the moon, you will need to add the projection for Enceladus for this data product.

image.png.e63e2b3418e19e9522b5593b13cd79d5.png

 

When I read the label file, I noticed this data product is a CASSINI EDR data. It is archived at PDS Imaging Node under volume https://pds-imaging.jpl.nasa.gov/data/cassini/cassini_orbiter/coiss_2042/ . I would not suggest to use this EDR directly in your crater counting.

If you read the “aareadme.txt” file in this volume, it said “The ISS team is not systematically performing calibration processing on the ISS EDRs.” However, their 'CALIBRATION' volumes (COISS_0xxx) “include all the necessary tools and documentation to support future users in performing their own calibration processing of the ISS EDR image datasets.” And the section “3.  Data Calibration“ of “aareadme.txt” has mentioned “The Cassini ISS archive volumes contain an extras directory that is included only on the eleventh Calibration volume. This directory contains the source code for the Cassini Imaging Science Subsystem Calibration (CISSCAL) software. This software, developed by the Cassini Imaging team, allows the user to radiometrically and geometrically process the EDR-level images into higher level calibrated images.”

You can also read the SIS file (https://pds-imaging.jpl.nasa.gov/data/cassini/cassini_orbiter/coiss_2042/document/edrsis.pdf) for more information. If you contact with the people at PDS Imaging Node, or people from the CASSINI team, they may provide expert help for you on this topic than I.

Thanks,

June

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...