read low resolution version of the data

[vincentsarago]

By design rio-tiler assume you are working within the native zoom range of your data (raw data = Max res, max res/number of overviews ~= minzoom).

When reading a file, we always use a VRT to align the data to the bounds/size we want to read. This is all defined in

rio-tiler/rio_tiler/utils.py

Lines 172 to 188 in ccf6aa0

	tile_transform = from_bounds(w, s, e, n, width, height)
	w_res = (
	tile_transform.a
	if abs(tile_transform.a) < abs(dst_transform.a)
	else dst_transform.a
	)
	h_res = (
	tile_transform.e
	if abs(tile_transform.e) < abs(dst_transform.e)
	else dst_transform.e
	)
	vrt_width = math.ceil((e - w) / w_res)
	vrt_height = math.ceil((s - n) / h_res)
	vrt_transform = from_bounds(w, s, e, n, vrt_width, vrt_height)
	return vrt_transform, vrt_width, vrt_height

(this part was copie from rasterio/rasterio#1373 (comment))

if you try to read a really low version of your data, we will first create a huge VRT and then ask to read a decimated part of it (this is to make sure we read the overview).

To be honest, for now I'm not sure there is a solution for this.