Embedded comparison map does not show raster tiles until I zoom - "Read failed" on raster tile requests

[j08lue]

How to reproduce

See comparison map below the scrollytelling feature in https://deploy-preview-481--visex.netlify.app/stories/darnah-flood

Look at the requests that are made as it loads and observe that no tiles show up and requests fail with 500.

When you zoom in, those tile requests succeed and data appears.

Cause?

The question is whether this is a backend service issue, a data issue (broken COG), or a frontend/configuration issue (whether the requests is even legal).

Either way, I think the 500 error is not very helpful here.

Re-tracing the requests

https://openveda.cloud/api/raster/searches/register

with payload:

{"filter-lang":"cql2-json","filter":{"op":"and","args":[{"op":">=","args":[{"property":"datetime"},"2023-09-07T00:00:00.000Z"]},{"op":"<=","args":[{"property":"datetime"},"2023-09-07T23:59:59.999Z"]},{"op":"eq","args":[{"property":"collection"},"darnah-flood"]}]}}

responded with:

    "links": [
        {
            "href": "https://openveda.cloud/api/raster/searches/27e9884f37bd3fc632658a84644b68dd/info",
            "rel": "metadata",
            "title": "Mosaic metadata"
        },
        {
            "href": "https://openveda.cloud/api/raster/searches/27e9884f37bd3fc632658a84644b68dd/{tileMatrixSetId}/tilejson.json",
            "rel": "tilejson",
            "templated": true,
            "title": "Link for TileJSON (Template URL)"
        },
        {
            "href": "https://openveda.cloud/api/raster/searches/27e9884f37bd3fc632658a84644b68dd/{tileMatrixSetId}/WMTSCapabilities.xml",
            "rel": "wmts",
            "templated": true,
            "title": "Link for WMTS (Template URL)"
        }
    ]
}

and then tile requests like

https://openveda.cloud/api/raster/searches/27e9884f37bd3fc632658a84644b68dd/tiles/WebMercatorQuad/13/4611/3306?assets=cog_default&bidx=1&title=VEDA+Dashboard+Render+Parameters&rescale=0%2C5000&resampling=bilinear&colormap_name=magma

fail with a 500 and

{"detail":"Read failed. See previous exception for details."}

[dzole0311]

I did some quick debugging and noticed that the 500 errors are consistently thrown starting at zoom level 12 and higher for this dataset. Hardcoding the zoom to 11 resolves the problem, so it seems to be specific to higher zoom levels and likely a backend issue rather than an illegal request format.

cc @anayeaye @smohiudd