Methods to handle continental size mosaics

[charalamm]

We are having a use case where we want to create and display a mosaic of the whole Africa at once and as far as I know eoAPI does not work well when it has to handle huge mosaics so I would like to open a discussion on possible solutions.

As a possible solution I am thinking of creating two collections for the same dataset:

• One collection containing the original high resolution raster files and having the purpose of being displayed in high zoom on the map
• The other collection containing processed rasters with low resolution and being displayed in low zoom levels

However this method would have the drawbacks:

• The frontend will need to use a different endpoint for different zoom levels
• There is a collection that has no usage other than demonstrative purposes
• Some resources are needed to calculate and save the low resolution rasters
• There is a dependency between the collections that might cause issues or be forgotten if or when updating the original collection

[vincentsarago]

@charalamm this is, sadly, a common issues where there is not a one good answer.

The raster service will be limited by the data resolution/size, the smaller your data is, the more files you'll need to open when creating low zoom level tiles.

To resolve this you could:

• change your input data to use larger COGs
• create another level of COGs (as you proposed) and have your frontend switch between the two mosaics based on zoom level

links:

• Improve performance of MosaicJSON tile requests at low zooms titiler#287 (reply in thread)
• multi-level mosaicJSON mosaicjson-spec#22