Display changes in tile function from v1 to current

[mike-amodeo]

I have a map tile service in production that was built in spring of 2020 off an old version of rio-tiler. I am not sure of the exact version, but it was version 1 because we are calling the tile function from main, which was renamed in version 2.0a1. We are preparing an update and were going to use the current version. However, we are getting different visual results and we cannot replicate the older output.

In the old version, we called tile from main without any options, and get this smoothed output

In the new version, we are calling tile from COGReader within a call of mosaic_reader

def reader(file, x, y, z, **kwargs):
        with COGReader(file) as image:
            return image.tile(x, y, z, **kwargs)

    try:
        img, _ = mosaic_reader(
            full_paths,
            reader,
            int(request["x"]),
            int(request["y"]),
            int(request["z"]),
            allowed_exceptions=(TileOutsideBounds, RasterioIOError),
        )
        tile = img.data[0]
        mask = img.mask

and getting results like below.

We want to replicate the smoothing along the color steps and have tried a few options within COGReader for the resampling_methods but have not had success yet. Was there a default setting in the old version that got changed in version 2 of rio-tiler that would cause this change? Is there a way for us to replicate the old experience in the new version with different settings? Thank you!

[vincentsarago]

@mike-amodeo sorry about this.

in ~1.x the tile method was using resampling_methods="bilinear"

rio-tiler/rio_tiler/utils.py

Lines 343 to 344 in 4286e55

	resampling_method="bilinear",
	tile_edge_padding=2,

but in the current version we use nearest (which is a safest choice)

rio-tiler/rio_tiler/reader.py

Line 33 in f72d57c

resampling_method: Resampling = "nearest",

[mike-amodeo]

Thanks, @vincentsarago . Not a problem. But when we tried adding the resampling_methods=bilinear in the call of COGReader, it was not working. Perhaps we had the wrong syntax. What is the best way to call this given our setup? Does this need to be in the mosaic_reader function or in tile?

[vincentsarago]

def reader(file, x, y, z, **kwargs):
        with COGReader(file) as image:
            return image.tile(x, y, z, **kwargs)

    try:
        img, _ = mosaic_reader(
            full_paths,
            reader,
            int(request["x"]),
            int(request["y"]),
            int(request["z"]),
            allowed_exceptions=(TileOutsideBounds, RasterioIOError),
            resampling_method="bilinear",
        )
        tile = img.data[0]
        mask = img.mask

☝️ should give the same result 🤞