Explore SOURCE_EXTRA (GDALWarpOptions) for tile tile_edge_padding

[vincentsarago]

@rowanwins, in #104 we introduced the tile_edge_padding argument but to me it seems that instead of doing so we could pass the tile_edge_padding to the WarpedVRT via the SOURCE_EXTRA keyword (see https://gdal.org/api/gdalwarp_cpp.html#structGDALWarpOptions).

Before doing anything I'd love to know how you produced the image from your initial post #56 (comment)

[rowanwins]

It was nothing too wild, I simply had a local version of rio-tiler running from which I requested two adjacent tiles with a get request and then wrote them to disk, I then stuck them next to each other in photoshop.

The effect was particularly pronounced on the data I was using which was a single band raster which had a range of -1 to 1.

Regarding moving to SOURCE_EXTRA I suspect you know far more about gdal than I do so I'm not sure I can contribute much useful thinking there, but happy to sanity check any results :)

[vincentsarago]

@rowanwins Thanks, I'll try to reproduce the test you did