Add segment IDs by their text labels programmatically? (with neuroglancer_segment_properties)

[j6k4m8]

Hey @jbms — I read through the docs and some comments in #199 and I don't think there's an easy way to do this currently:

If I have a segmentation channel with IDs [1, 2, 3, 4] and a neuroglancer_segment_properties info that looks like this:

{
    "inline": {
        "ids": ["1", "2", "3", "4"],
        "properties": [{
            "type": "label",
            "id": "label",
            "values": ["John", "Paul", "George", "Ringo"]
        }]
    }
}

Is there an easy way to add Ringo to the segments array of my ngl state object at pageload, if I don't know what ID that corresponds to?

Right now, I need to know that Ringo corresponds to segment "4" so that I can populate state like this:

... // in `layers[]`
{
    "type": "segmentation",
    "source": [
      "precomputed://.../segmentation",
      "precomputed://.../properties"
    ],
    "tab": "source",
    "segments": [
      "4",                             // Works
      "Ringo"                          // Doesn't Work
    ],
    "name": "segmentation"
},
...

Is there a way for me to specify the label instead of the segment ID, and let neuroglancer run the lookup at load time?

[jbms]

Unfortunately there is not.

[j6k4m8]

Got it, thank you for the quick response! Would our adding support for this be a useful contribution, or is it this way for a reason?

[jbms]

It hasn't exactly come up before. The segmentQuery layer property allows you to specify a query, but the user would still then need to actually select the segments included in the query.

Do you have a specific use case in mind where it would be difficult to just look up the actual id?

[j6k4m8]

Got it! My proposed use cases would be something like:

• I ask for a rendering of a brain, with certain brain regions in an atlas already rendered
• I ask for segments from a dataset (such as C. elegans) where neurons have explicit names

All of this could be done by querying the properties json separately before rendering ngl state, so this is not blocking science :)