Support for TMS/XYZ inputs - not only COGs

[jo-chemla]

Hey there, probably a bad idea, if so please disregard and close the request!
I'm looking to build a browser, client-side, tiles downloader - which would eg be the equivalent to

• Qgis Save Raster Layer as on a TMS raster source with given resolution and extent
• or Gdal gdal_translate -projwin minx maxy maxx miny -projwin_srs EPSG:4326 -outsize 4096 0 source_tms.xml output_4096.tif where the source_tms.xml references the ServerUrl as shown in this post

At the moment, I can reproduce this in TiTiler for an input COG using the /cog/crop/{minx},{miny},{maxx},{maxy}[/{width}x{height}].{format} GET endpoint from an input COG. Would love to be able to do this for a TMS/XYZ input as well, so I could use TiTiler as a middleware to download cropped images from TMS urls.
I could try using loam wasm gdal warper, but does not seem to support tms source inputs, same for geotiff-js.
[Edit]: might be interesting to look at gdal3.js which might accept TMS input sources while loam does not, but needs a little investigation.

[vincentsarago]

@jo-chemla there is no such thing as bad idea!

It's already possible 😅, instead of passing a simple url (e.g {endpoint}/tilejson.json?url=cog.tif) you can pass a GDAL wmts string: https://titiler.xyz/cog/crop/-69.99510242702613,41.85313673098173,-69.99038118408833,41.857529724573766.png?url=WMTS%3Ahttp%3A%2F%2Ftitiler.xyz%2Fcog%2FWMTSCapabilities.xml%3Furl%3Dhttps%3A%2F%2Fnoaa-eri-pds.s3.amazonaws.com%2F2022_Pre_Event%2FEC2201a_OB_N_RGB%2FEC2201a_OB_N_C0700000w415145n.tif%26bidx%3D1%26bidx%3D2%26bidx%3D3%26tile_format%3Dpng&unscale=false&resampling=nearest&max_size=128&return_mask=true

see #555 (comment)

[jo-chemla]

Woosh, looks exactly like what I need, thank you so much! Incredible all that can be done with TiTiler :)

[jo-chemla]

Sorry I think I got excited too quickly - before really decoding the url param with the wmts string. What I'd actually like to merge/crop are TMS/XYZ tiles with url like http://domain.com/tileset_1/{z}/{x}/{y}.png rather than a WMTS endpoint.

I don't know lots of ways to transform a TMS url to a WMTS capable server - one is using mapproxy with the below config file ¹ for reference, but this would defeat the purpose of a pure client-side TMS/XYZ tiles merger/cropper.

So, by digging a bit the list of gdal raster drivers, I found the TMS mini-driver within the WMS driver. So I tried to use the following url, URL-encode it, and use it as the url param of the TiTiler crop endpoint, with no luck atm. Do you think I'm stepping in the right direction?

Note the WMS strings are these of the gdal WMS driver example here for osm and there for google

WMS:<GDAL_WMS><Service name="TMS"><ServerUrl>http://domain.com/tileset_1/${z}/${x}/${y}</ServerUrl></Service><DataWindow><UpperLeftX>-20037508.34</UpperLeftX><UpperLeftY>20037508.34</UpperLeftY><LowerRightX>20037508.34</LowerRightX><LowerRightY>-20037508.34</LowerRightY><TileLevel>18</TileLevel><TileCountX>1</TileCountX><TileCountY>1</TileCountY><YOrigin>top</YOrigin></DataWindow><Projection>EPSG:3857</Projection><BlockSizeX>256</BlockSizeX><BlockSizeY>256</BlockSizeY><BandsCount>3</BandsCount><Cache /></GDAL_WMS>

services:
demo:
tms:
  use_grid_names: true
  origin: 'nw'
kml:
    use_grid_names: true
wmts:
wms:
  md:
    title: MapProxy WMS Proxy
    abstract: MapProxy serving custom XYZ scheme tiles.

layers:
- name: layer_1
  title: layer_1
  sources: [cache_1]

caches:
cache_1:
  grids: [osm_grid]
  sources: [source_1]

sources:
source_1:
  type: tile
  url: http://domain.com/tileset_1/{z}/{x}/{y}.png
  grid: webmercator

Footnotes

1. ↩

[jo-chemla]

Note to future-self: the /cog/crop/ endpoint was replaced to /cog/bbox/ at titiler version 0.15.0 (and /cog/feature/ POST)

[jo-chemla]

Hi again,
Don't know why but it seems like my final answer was deleted. I managed to do it following your advice, with the following URL:

For standard TMS servers:: URL-encode this XML string:

https://titiler.xyz/cog/crop/-110,-70,110,70.png?url=<GDAL_WMS><Service name='TMS'><ServerUrl>http://example.com/tileset1/${z}/${x}/${y}</ServerUrl></Service><DataWindow><UpperLeftX>-20037508.34</UpperLeftX><UpperLeftY>20037508.34</UpperLeftY><LowerRightX>20037508.34</LowerRightX><LowerRightY>-20037508.34</LowerRightY><TileLevel>18</TileLevel><TileCountX>1</TileCountX><TileCountY>1</TileCountY><YOrigin>top</YOrigin></DataWindow><Projection>EPSG:3857</Projection><BlockSizeX>256</BlockSizeX><BlockSizeY>256</BlockSizeY><BandsCount>3</BandsCount><Cache /></GDAL_WMS>

Similar than for a WMS compliant server: https://titiler.xyz/cog/crop/-110,-70,110,70/512x0.png?max_size=512&url=WMS:http://ows.terrestris.de/osm/service?layers=OSM-WMS-no-labels

[vincentsarago]

🤯

[jo-chemla]

Yep pretty sweet, incredible what can be done with TiTiler, thanks a lot for your help!

[vincentsarago]

it's all GDAL magic 🥳

[jo-chemla]

Hey there, another following quick question: using the gdal_translate with the wms string and the /cog/crop endpoint results in slightly different images, because of the CRS of the image:

• epsg;3857 for the gdal_translate image
• epsg:4326 for the titiler tiff image.

Is it possible to modify the output CRS of the /cog/crop/ image in titiler? Tried using the coord-crs url parameter, but it's resulting in a server error - and should probably just modify the crop bounds interpreted crs.

Error seems to be: {"detail":"Bounds and transform are inconsistent"} (probably because wrong ordering of min max in 3857) or {"message":"Internal Server Error"}

Edit: url tested

[vincentsarago]

You are right,

When using the Crop endpoint, we will return the image in the bounds CRS (epsg:4326 by default, or coord-crs). we do not have an option to add dst_crs yet but we could.

Can you open a new Feature Request issue and ask for dst-crs to be added in the preview and crop endpoint 🙏

[jo-chemla]

Already great that the cropped image is returned in the bounds CRS, thanks!
Although in my case, it results in an 500 internal server error when I try to do so with 3857 bounds on my WMS string - tried with several endpoints, internal, google, bing, esri etc.
Edit: Just opened the Feature Request for the dst_crs, thanks again!