Question: have key wildcard to serve multiple geotiffs as mosaic

[gillesserco]

Hello

I use a terracotta server to serve dated terrain change detection geotiffs over several zones. The tiffs are square tiles and they are uniquely spatially identified by their UTM projection position (like '29N_22E-184N') that is present in the file naming.

I use keys like "provider/type/date/projcell/band", projcell being the UTM info like 29N_22E-184N.

All is perfect and I can from my custom UI select the cell I want by navigating the keys down and I see the tile on a map component + on a dedicated panel.

I would be very interested in having the possibility to see 'mosaics' on the UI without generating the mosaics of my zones. 
I did a test adding a 'disposition' key to be able to select 'mosaic/tile', then did a call using the disposition key 'mosaic' and omitting the projcell key: the server replied: "must specify all key except last one".

Question: 
 - would it be possible to change the code to support wildcards for one or several keys? or to be able to omit a key? 
 - does someone have a way of doing this mosaic-like usage of terracotta?

Thanks & best regards

Gilles

[j08lue]

Terracotta currently does not support mosaics - reading from different rasters depending on position on the map. Every dataset (key combination) points to a single raster and only for RGB we allow the last key to be used to specify the RGB bands.

TiTiler has support for the MosaicJSON, where you basically pass a URL to a MosaicJSON (which contains links to your rasters) to the [/mosaic] (https://developmentseed.org/titiler/endpoints/mosaic/) endpoint, which then handles the lookup etc.

In contrast to Terracotta, you have to handle the lookup of your raster URLs outside of the service with TiTiler - mapping dates to URLs etc.

For Terracotta, your only options are to

1. merge the tiles into one (big) raster
2. add layers for all the GeoTIFFs to your client - only makes sense for a few files, though, and will multiply your Terracotta API calls.