Add geolookup operator

plugins/tiddlywiki/geospatial/demo/cities/NewYork.tid

@@ -0,0 +1,8 @@
+title: $:/plugins/tiddlywiki/geospatial/demo/cities/NewYork
+tags: $:/tags/GeoMarker
+caption: New York
+lat: 40.712778
+long: -74.006111
+alt: 0
+
+This is New York!

plugins/tiddlywiki/geospatial/demo/ui/geomarker.tid

@@ -87,6 +87,21 @@ title: $:/plugins/tiddlywiki/geospatial/demo/ui/geomarker
 </ul>
 </$let>
 
+!! GeoLayer Lookups
+
+<$let
+	thisLocation={{{ [geopoint{!!long},{!!lat}] }}}
+>
+<ul>
+<$list filter="[all[shadows+tiddlers]tag[$:/tags/GeoLayer]sort[caption]]">
+<li>
+<$text text={{{ [<currentTiddler>get[caption]] :else[<currentTiddler>] }}}/> --
+<$text text={{{ [<thisLocation>geolookup{!!text}] }}}/>
+</li>
+</$list>
+</ul>
+</$let>
+
 !! Travel Time
 
 <$button actions=<<get-traveltime-actions>>>

plugins/tiddlywiki/geospatial/operators/lookup.js

@@ -0,0 +1,45 @@
+/*\
+title: $:/plugins/tiddlywiki/geospatial/operators/lookup.js
+type: application/javascript
+module-type: filteroperator
+
+Filter operators for geospatial lookup
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var turf = require("$:/plugins/tiddlywiki/geospatial/turf.js"),
+	geotools = require("$:/plugins/tiddlywiki/geospatial/geotools.js");
+
+exports.geolookup = function(source,operator,options) {
+	// Get the GeoJSON object
+	var output = [],
+		jsonObject = $tw.utils.parseJSONSafe(operator.operands[0],null);
+	if(jsonObject) {
+		// Process the input points
+		source(function(tiddler,title) {
+			var point = geotools.parsePoint(title),
+				result = getPolygonsContainingPoint(jsonObject,point);
+			output.push(JSON.stringify(result))
+		});
+	}
+	// Perform the transformation
+	return output;
+};
+
+function getPolygonsContainingPoint(featureCollection,point) {
+	// Filter the GeoJSON feature collection to only include polygon features containing the point
+	const properties = [];
+	turf.featureEach(featureCollection,function(feature) {
+		if(feature.geometry.type === "Polygon" && turf.booleanPointInPolygon(point,feature)) {
+			properties.push(feature.properties);
+		}
+	});
+	return properties;
+}
+
+})();

plugins/tiddlywiki/geospatial/tests/operators/geolookup.tid

@@ -0,0 +1,60 @@
+title: $:/plugins/tiddlywiki/geospatial/tests/geolookup
+description: geolookup operator
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\whitespace trim
+<$text text={{{ [geopoint[100.5],[0.5]geolookup{TestData}jsonget[0],[animal]] }}}/>
++
+title: TestData
+type: application/json
+
+{
+	"type": "FeatureCollection",
+	"features": [
+		{
+			"type": "Feature",
+			"geometry": {
+				"type": "Point",
+				"coordinates": [102.0,0.5]
+			},
+			"properties": {
+				"animal": "amoeba"
+			}
+		},
+		{
+			"type": "Feature",
+			"geometry": {
+				"type": "LineString",
+				"coordinates": [
+					[102.0,0.0],[103.0,1.0],[104.0,0.0],[105.0,1.0]
+				]
+			},
+			"properties": {
+				"animal": "snake",
+				"length": 100.0
+			}
+		},
+		{
+			"type": "Feature",
+			"geometry": {
+				"type": "Polygon",
+				"coordinates": [
+					[[100.0,0.0],[101.0,0.0],[101.0,1.0],[100.0,1.0],[100.0,0.0]]
+				]
+			},
+			"properties": {
+				"animal": "boxfish",
+				"prop1": {
+					"this": "that"
+				}
+			}
+		}
+	]
+}
++
+title: ExpectedResult
+
+<p>boxfish</p>