Terrain Data and Processing Tips

[connorjak]

Rules & Info	SpaceTeamsROS	Q&A Discussions Category

Info on where to download and how to process the terrain data will be here. You can use the comments section below to ask questions about this.

Source Datasets:

• HiRISE DTM 2m/pix
  • https://hirise.lpl.arizona.edu/dtm/ESP_039245_1325
  • All waypoints should be within the dataset bounds
• (Not used as the primary altitude dataset in Space Teams) HiRISE DTM 1m/pix
  • https://www.uahirise.org/dtm/PSP_007110_1325

Download the DTM here. The other files are not the raw dataset values, but may be useful for visualization.

Opening and processing the data:

• https://hirise.lpl.arizona.edu/dtm/about.php
• https://hirise.lpl.arizona.edu/dtm/howto.php

Some common python libraries used for opening and processing HiRISE DTMs:

• osgeo.gdal https://gdal.org/en/stable/api/python/osgeo.gdal.html
• rasterio https://rasterio.readthedocs.io/en/stable/

Example

Nick Dominguez, who is on our team, made an example of using osgeo.gdal to make an elevation-sampling ROS service. I haven't included all of the files involved in making this work in ROS, but here is the core of that example. This code hasn't been extensively tested.

dem_server.py
ElevationQuery.srv.txt

[shafinawake]

I downloaded the 41MB data and

1. when I'm trying to open it, giving me a error message stating "the disc image file is corrupted"
2. windowns wasn't letting me download it showing it could harm my device
3. Facing the same downloading issue of Gullied Crater in Kaiser Crater Dune Field

[connorjak]

The .img file is only openable by a few programs that support reading DTMs in this format. We posted the LPL's help info above for how to open and process this data.

[shafinawake]

Sorry I overlooked and Thanks

[shafinawake]

Hello chief, I do get an image following the steps but it'd be really helpful for us if we get as co-ordinates

[connorjak]

Oh sorry looks like I missed responding to this. It may or may not be necessary to use the GDAL Translate tool in Python or another distribution such as the osgeo4w shell to convert the .img to .tiff (GeoTIFF).

An easy way I have used to set up the osgeo4w shell is use the QGIS installer. Other ways are valid too.

You can then use the osgeo python libraries gdal and osr to do coordinate transformations from latitude and longitude or another coordinate to pixel coordinates and sample altitude values. We provide example code of this above where we implemented a ROS service for altitude queries.

[connorjak]

Here is another set of helpful info about HiRISE DTMs: https://stac.astrogeology.usgs.gov/docs/data/mars/hirise_dtms/