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Comment by bryik | Hacker News Reader

Cool project!

A year or two ago, I used A-Frame to visualize some of NASA's Martian terrain data[1]. The hardest part was processing it. QGIS could not understand the projection, so slicing out a parcel of land and lining it up with a texture was messy. The best output format was obscure (ENVI) and required arcane GDAL commands to produce. For a GIS noob, it was a lot to handle.

But with this component, all you need to do is specify lat and lon--can't get much easier than that! The repo suggests that different data sources can be used[2], I wonder how hard it would be to standup a Martian terrain source?

1 - Github: https://github.com/bryik/aframe-terrain-model-component Example: https://www.wsundine.com/misc/noctis-terrain

2 - https://github.com/anselm/aterrain/blob/master/src/TileServe...

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Having played with geospatial a lot in the past, both "manually" and using libraries like cesium.js (which a lot of this is based on), my gut reaction is "I have no idea how hard it is." ;)

Joking aside, I'm not sure. As you know, the math in the libraries and the datasets are tightly coupled to the projection model (e.g., on earth, things come back to ECEF coordinates, what cesium calls FIXED, and models of the planet like WGS84). So, I would suspect that this work could serve as a model, but a bunch of the internal math would need to change. Assuming there is a well defined model of Mars that can be used, akin to WGS84, and you can massage all the datasets into a form that can be reliably mapped to it, like AGI/Cesium has done with the geospatial data we are using, it should be possible.

I know we would love to see someone do this, inspiring projects like this is one reason we release things in the open. Heck, you could imaging a new set of options for the a-terrain component that specified the globe model somehow ("WGS84, MARS18") and a base URL for the data server ...

I'm using a spherical model for simplicity. Although I'm fetching image tiles and suchlike I reproject from mercator directly to spherical for simplicity rather than the slightly ellipsoidal model.

And the image tile source and elevation tile source and radius of the sphere is a user settable attribute from the <a-terrain> tag. If you simply set the right radius and image tile source in html - you would have a working mars view... I believe. I can ask Cesium if they have some official sources for this.

This is very cool by the way. Would be fun to collaborate in some way.

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