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Add statstics for visualization to bands or assets #157
Description
ol-stac attempts to generate a default visualization for assets displayed on a map. Without additional metadata, it typically falls back to stretching values from the minimum to the maximum, which is prone to outliers and can result in poorly balanced visualizations.
By including statistical metadata such as min, max, median, and stddev, we can compute better visualizations; for example, using the mean ± 2σ (~95% of values) for a better visualization stretch instead of the full min/max extent (and if no min/max is provided, the min/max is the actual data type min/max).
I've looked through zarr.json for any statistical values but couldn't find any, and the STAC metadata doesn't include them either.
Any ideas on how to improve this? Specifically, would it be feasible to add statistics to the STAC assets and/or bands?
Activity
m-mohr commentedon Apr 17, 2026
Example for COGs:
STAC: https://github.com/stac-extensions/label/blob/main/examples/spacenet-roads/roads_source.json
With statistics:
Without statistics:
vincentsarago commentedon Apr 21, 2026
could be nice to create a
statisticszarr convention which tell themin/max/mean/median/stdevvalues for arraysemmanuelmathot commentedon Apr 28, 2026
from WP1 meeting. We would need both Zarr and STAC level. For Zarr, a new convention would be useful.
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lhoupert commentedon Oct 16, 2026
@claxn @shollendEODC can you add these statistics when creating new STAC items? we would need that for being able to visualise assets map on stac browser . See the issue described in more details here: EOPF-Explorer/data-pipeline#105 (comment)
m-mohr commentedon Oct 16, 2026
Ideally it would contain:
claxn commentedon Oct 20, 2026
@lhoupert @m-mohr Makes sense, I will implement it after the other PRs are solved and will follow the common metadata spec (https://github.com/radiantearth/stac-spec/blob/master/commons/common-metadata.md#statistics-object). According to existing conventions, e.g., what GDAL adds to the GeoTIFF header, the values refer to the used data type, so encoded values. not physical values (as you already discuss in EOPF-Explorer/data-pipeline#105 (comment)).