Get Layer-List (Information) Activity

Non planifiée

Holger Frommer

10 décembre 2024 13:11

We use several layer-presets. One specific layer is not included in all presets. I have designed a specific tool which should only be active if this layer is included in the current layer-list. Otherwise, the tool should show a message (eg "Layer not included"), and be deactivated. 

To do so I need an activity to retrieve information about the layer-list, like “Get Layer-List”. This should include if a layer is included or not.

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  Gareth Evans

  11 décembre 2024 01:25 Modifié

  Hi Holger Frommer while I do not believe there is a workflow activity that specifically tells you whether or not a layer is present in the map, I believe you can accomplish this logic using the findByLayerId function that is available on the allLayerExtensions object. 
  
  Here's how you can structure the expression, likely in a Create Value or an If statement:

  $mapInfo.map.extension.allLayerExtensions.findByLayerId("YOUR_LAYER_ID") != null;
  
  Explanation:

  1. $mapInfo.map.extension.allLayerExtensions:
     • Accesses the collection of all layer extensions in the current map.
  2. .findByLayerId("YOUR_LAYER_ID"):
     • Searches this collection for a layer with the ID YOUR_LAYER_ID.
  3. != null:
     • Checks whether the findByLayerId method returned a valid layer extension. If it’s null, the layer is not included in the current map.
  4. $isLayerIncluded:
     • A variable or property to store the result of the check. It will be true if the layer is included, and false otherwise.

  
  From there, you can use a few other workflow activities that determine the behaviour after that check is evaluated.

  
  All that to be said, I do agree this could be a useful workflow activity. It could essentially wrap the logic described above.

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  Holger Frommer

  11 décembre 2024 08:46

  Hi Gareth,

  Thank you very much. I wasn't aware of this possibility.

  Unfortunately I can't get it to work. Since I found no proper documentation on the .extensions and .allLayerExtensions objects, maybe I can ask for further help?

  I wrote a small workflow to test for the layer “Netzknoten”, showing an alert (true or false). 

  

  The result is always “false”, even though the layer is included in the map. Guess I can't use the name/string of the layer (like in the Get Layer activity)? 

  “Netzknoten” is a group-layer, by the way, and in the final workflow I would have to adress a sub-layer ("ZEB" or 0). Is that possible with the .findByLayerID function?

  Thanks a lot in advance.

  Greetings from Munich,

  Holger

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  Berend Veldkamp

  13 décembre 2024 13:06

  Are you sure Netzknoten is the actual ID of the layer, and not just the title?

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  Holger Frommer

  14 décembre 2024 15:23

  “Netzknoten” is one of several group-layers in the webmap. It is published with its sublayers in ArcGIS Pro as a map image layer. In the Portal, only the sublayers have an ID. The map image layer only comes with a “Service Item ID”.

  In the Get Layer-Activity in another workflow, I can use the name of the group-layer, and the ID of the sublayer.

  

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  Berend Veldkamp

  17 décembre 2024 07:37

  If it's a mapservice, you should use the id of the service layer. The sublayer is the id of the layer within that service

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