Is it possible to mask rendered mosaic tiles using a GeoJSON?

[hrodmn]

I can apply an intersects filter to my mosaic search to limit the mosaic to STAC items that intersect a geometry, but is it be possible to use a GeoJSON to mask pixels in the rendered tiles?

e.g. I want to crop the rendered output so that I can only see pixels on the left side of the purple line:

[vincentsarago]

👋 @hrodmn

That's interesting and TBH I didn't thought about this before but yeah it might make some sense to mask the images when there is a spatial filter in play.

It might be quite tricky to do it natively in titiler-pgstac but rio-tiler/GDAL has ways to do this:

• https://cogeotiff.github.io/rio-tiler/advanced/feature/
• Cropped Tiles developmentseed/titiler#376 (comment)

I think the easiest way to do this will be the apply the mask after tile creation, but it means that you'll have to rasterize the geometry on each tile call, and if the geometry is complex then it might slow down the process.

The other solution is to pass a Cutline to the COG Reader but this might involve more work.

[hrodmn]

Thanks for the suggestions, @vincentsarago! I'll them it out. I thought about it some more last night and for my application it might be simpler to mask the tiles using javascript on the client side, though. I haven't tried it out yet but will let you know what I find!