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To complete the existing function layer_property(...), this change add a new argument 'distance_units' for return a string with the layer distance units (see QgsUnitTypes::DistanceUnit) This function can be used for display units for labels, in layouts or for access to more layer properties in the expression builder for algorithms.
15 lines
1.6 KiB
Plaintext
15 lines
1.6 KiB
Plaintext
{
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"name": "layer_property",
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"type": "function",
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"description": "Returns a matching layer property or metadata value.",
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"arguments": [
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{"arg":"layer", "description":"a string, representing either a layer name or layer ID"},
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{"arg":"property", "description":"a string corresponding to the property to return. Valid options are:<br /><ul><li>name: layer name</li><li>id: layer ID</li><li>title: metadata title string</li><li>abstract: metadata abstract string</li><li>keywords: metadata keywords</li><li>data_url: metadata URL</li><li>attribution: metadata attribution string</li><li>attribution_url: metadata attribution URL</li><li>source: layer source</li><li>min_scale: minimum display scale for layer</li><li>max_scale: maximum display scale for layer</li><li>is_editable: if layer is in edit mode</li><li>crs: layer CRS</li><li>crs_definition: layer CRS full definition</li><li>crs_description: layer CRS description</li><li>extent: layer extent (as a geometry object)</li><li>distance_units: layer distance units</li><li>type: layer type, e.g., Vector or Raster</li><li>storage_type: storage format (vector layers only)</li><li>geometry_type: geometry type, e.g., Point (vector layers only)</li><li>feature_count: approximate feature count for layer (vector layers only)</li><li>path: File path to the layer data source. Only available for file based layers.</li></ul>"}
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],
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"examples": [
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{ "expression":"layer_property('streets','title')", "returns":"'Basemap Streets'"},
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{ "expression":"layer_property('airports','feature_count')", "returns":"120"},
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{ "expression":"layer_property('landsat','crs')", "returns":"'EPSG:4326'"}
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]
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}
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