Identify tool on GeoTIFF layers reports RGB values, not data values

[mfisher87]

JupyterGIS version

No response

Description

It should report the underlying values of all the bands at a given point, but instead it reports 0-255 RGB values. For example, geotiff-example.tif has band values ranging from 0-65535.

[nakul-py]

I think the bug is because of this in case WebGlLayer

[mfisher87]

I think that's true, but I'm not sure offhand how to get a data value instead of a pixel color value. Any idea?

[nakul-py]

I am also finding how to get raw values from GeoTIFFsource

[nakul-py]

I think we need help of @gjmooney!

[gjmooney]

It should report the underlying values of all the bands at a given point, but instead it reports 0-255 RGB values. For example, geotiff-example.tif has band values ranging from 0-65535.

I'm pretty sure this is dependent on if normalize is selected when adding the layer.

Here's the values of geotiff-example.tif from the identify tool when normalize isn't set.

[nakul-py]

Thanks @gjmooney You are absolutely correct :).

[nakul-py]

Hey @mfisher87 and @gjmooney I think we can add some more information about identify tool usage on Geotiff layers.

[mfisher87]

We have other reasons to disable normalize as well! Let's do it :) #963

Hey @mfisher87 and @gjmooney I think we can add some more information about identify tool usage on Geotiff layers.

Can you clarify what kind of information you'd like to display?

[nakul-py]

I think the information should be something like

💡Tip: For GeoTIFF layers, one can view raw band values by unchecking the "Normalize" option in the Object Properties

[gjmooney]

Some type of little info box that pops up on hover with a short explanation of the what each option does would be a good idea.

[mfisher87]

Agreed. We could add a "description" to that field in the schema and that should display as a label.

But do we want to offer the option to normalize at all? What's the use case? Why not always have normalize turned off?

[nakul-py]

Why not always have normalize turned off?

Currently if we turn off normalize to see raw band values the full map is covered with one color only. Any Reason?

[nakul-py]

Now i can see raw band values by the help of two same geotiff layers. In both we have to set same colormap and the layer which has not normalize option checked has to be opacity 0.2 or something low so we can see raw bands value easily.

Screencast.From.2025-10-23.11-10-21.mp4

[nakul-py]

@mfisher87 For now I have added descriptions 964