I'm doing some analysis on these InSAR vertical displacement ImageServers published by California Department of Water Resources - also visualized in their public data viewer. I successfully loaded them into QGIS 3.20 as an ArcGIS REST Server. However, I am not able to see or analyze the actual pixel values of the raster, which represent the vertical displacement in feet. Exporting to GeoTIFF or geopackage produces a raster with the RGB values of the default symbology. I have tried changing the output mode from rendered image to raw data with no effect. The sample raster tool yielded NULL values. Ultimately I would like to be able to perform zonal statistics on the interpolated vertical displacement value within a single groundwater basin.
The Department confirmed the image services carry the RGB values of the default symbology and the raw pixel values. Their tech only works in ESRI so is not sure how to get the values in QGIS. In ArcGIS Pro, the solution to expose the raw values is layer properties -> set processing template = none:
How can I implement this solution in QGIS?
I am not able to find a similar option to "processing template" in layer or image service properties.