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48 lines
2.6 KiB
Plaintext
48 lines
2.6 KiB
Plaintext
{
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"name": "overlay_within",
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"type": "function",
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"groups": ["GeometryGroup"],
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"description": "Returns whether the current feature is spatially within at least one feature from a target layer, or an array of expression-based results for the features in the target layer that contain the current feature.<br><br>Read more on the underlying GEOS \"Within\" predicate, as described in PostGIS <a href='https://postgis.net/docs/ST_Within.html'>ST_Within</a> function.",
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"arguments": [{
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"arg": "layer",
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"description": "the layer whose overlay is checked"
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}, {
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"arg": "expression",
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"description": "an optional expression to evaluate on the features from the target layer. If not set, the function will just return a boolean indicating whether there is at least one match.",
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"optional": true
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}, {
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"arg": "filter",
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"description": "an optional expression to filter the target features to check. If not set, all the features will be checked.",
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"optional": true
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}, {
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"arg": "limit",
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"description": "an optional integer to limit the number of matching features. If not set, all the matching features will be returned.",
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"optional": true
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}, {
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"arg": "cache",
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"description": "set this to true to build a local spatial index (most of the time, this is unwanted, unless you are working with a particularly slow data provider)",
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"optional": true,
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"default": "false"
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}],
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"examples": [{
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"expression": "overlay_within('regions')",
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"returns": "TRUE if the current feature is spatially within a region"
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}, {
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"expression": "overlay_within('regions', filter:= population > 10000)",
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"returns": "TRUE if the current feature is spatially within a region with a population greater than 10000"
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}, {
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"expression": "overlay_within('regions', name)",
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"returns": "an array of names, for the regions containing the current feature"
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}, {
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"expression": "array_to_string(overlay_within('regions', name))",
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"returns": "a string as a comma separated list of names, for the regions containing the current feature"
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}, {
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"expression": "array_sort(overlay_within(layer:='regions', expression:=\"name\", filter:= population > 10000))",
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"returns": "an ordered array of names, for the regions containing the current feature and with a population greater than 10000"
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}, {
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"expression": "overlay_within(layer:='regions', expression:= geom_to_wkt($geometry), limit:=2)",
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"returns": "an array of geometries (in WKT), for up to two regions containing the current feature"
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}],
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"tags": ["predicate", "current", "contain", "target", "array", "geos", "described", "underlying", "features"]
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}
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