topic Re: Help converting .IMG files to .TIF in ArcGIS Pro Questions

Help converting .IMG files to .TIF

matteatsbrains — Wed, 06 Mar 2024 14:50:59 GMT

Hello, I am very green with ArcGIS Pro so I hope this is the correct place to ask. I would like to do some slope analysis on data I have downloaded from the HiRISE website (specifically this: https://www.uahirise.org/ESP_016671_1615). However when I run slope analysis on the JP2 file I download it comes out as a massive blob of colours. I've read that I would need to convert the .IMG file to something arc could read but I have no clue how to do this. Would anybody be able to help me?

Thanks 🙂

First image is what I have downloaded, seccond is... the blob

Re: Help converting .IMG files to .TIF

BobBooth1 — Wed, 06 Mar 2024 15:07:45 GMT

That looks like a hillshade product. You need a terrain model (showing actual elevation values at those locations) in order to do slope analysis.

Looks like they have some such models here:

https://www.uahirise.org/hiwish/maps/dtms.jsp

Once you have a DEM/DTM, you can add it to ArcGIS Pro and try the Slope tool on it.

You can convert raster file formats in Pro:

https://pro.arcgis.com/en/pro-app/3.1/help/data/imagery/export-or-convert-raster-datasets.htm

Re: Help converting .IMG files to .TIF

matteatsbrains — Wed, 06 Mar 2024 15:12:27 GMT

Hey Bob, just so I have this right, that would mean that I could only run slope analysis on the files they have DTMs of. There would be no way to convert the .IMG?

Re: Help converting .IMG files to .TIF

BobBooth1 — Wed, 06 Mar 2024 15:20:00 GMT

You can't run a slope analysis on imagery of different color band values (like a photo, or a landsat image). You need a raster that contains elevation values. If that image is a hillshade (it looks like it is), that implies that they have a corresponding DEM, because hillshades, like slopes are a product derived from a DEM.

Re: Help converting .IMG files to .TIF

BobBooth1 — Wed, 06 Mar 2024 15:25:13 GMT

It looks as though they have 1,079 DEMs hosted here:

https://www.uahirise.org/dtm/

Tools exist to create DEMs from stereo pairs of images, so if they don't have a DEM for this site (I'll bet they do), if they have stereo image pairs for the site, with additional software and training, you could make a DEM. That would be a much bigger lift than downloading an existing DEM and running a slope analysis.

Re: Help converting .IMG files to .TIF

matteatsbrains — Wed, 06 Mar 2024 16:34:43 GMT

Ahh right so a bit above the pay grade of an undergrad. Thanks for the help mate! 🙂