Got continents working. Very slow though - should simplify them using e.g. Concaveman.

src/geo_store.js

@@ -7,6 +7,7 @@ var g_GeoStore = {
     areas: {},
     area_query_results: {},
     image_index: {},
+    static_areas: {},
 };
 
 export function hash_geo_area(geo_area) {
@@ -147,10 +148,51 @@ export function image_in_area(image_id, area_hash) {
 export function load_static_geo_polygons() {
     return new Promise((resolve, reject) => {
         fetch('/continent_polygons.geojson')
-        .then(res => res.json())
-        .then(json => {
-            console.log("Continents:", json);
-            resolve(json);
-        });
+            .then(res => res.json())
+            .then(json => {
+                // The continents are stored as an array of features. Change it to a
+                // dictionary of name to geometry.
+                json.features.forEach(feature => {
+                    g_GeoStore.static_areas[feature.properties.continent] = feature.geometry;
+                });
+                resolve();
+            });
     });
+}
+
+export function query_geometry(query) {
+    return new Promise((resolve, reject) => {
+        const query_words = query.toLowerCase().trim().split(/\s+/);
+        for(var key in g_GeoStore.static_areas) {
+            const static_words = key.toLowerCase().trim().split(/\s+/);
+            if(query_words.length == static_words.length) {
+                var match = true;
+                for(let i=0; i<static_words.length; i++) {
+                    if(static_words[i] != query_words[i]) {
+                        match = false;
+                        break;
+                    }
+                }
+                if(match) {
+                    // Matched a static geometry in our store.
+                    resolve({
+                        display_name: key,
+                        geojson: g_GeoStore.static_areas[key],
+                    });
+                    return;
+                }
+            }
+        }
+        // No match in our store, query Nominatim instead
+        fetch("https://nominatim.openstreetmap.org/search?polygon_geojson=1&polygon_threshold=0.001&format=json&limit=5&q=" + query)
+        .then(res => res.json())
+        .then(jsonres => {
+            if (Array.isArray(jsonres) && jsonres.length > 0) {
+                resolve(jsonres[0]);
+            }
+            resolve(false);
+            return;
+        })
+        .catch(e => reject(e));
+    })
 }

src/userquerywidget.js

@@ -34,6 +34,7 @@ import {
     TimeFilter, ImageTypeFilter, ImageTypeEnum, LocationFilter
 } from './queries.js'
 import { Typography } from '@material-ui/core';
+import { query_geometry } from './geo_store.js';
 
 const useStyles = makeStyles(theme => ({
     root: {},
@@ -90,11 +91,12 @@ export function EditLocationFilterExpression(props) {
             return;
         }
 
-        fetch("https://nominatim.openstreetmap.org/search?polygon_geojson=1&polygon_threshold=0.001&format=json&limit=5&q=" + query)
-            .then(res => res.json())
-            .then(jsonres => {
-                if (Array.isArray(jsonres) && jsonres.length > 0) {
-                    updateProposal(jsonres[0]);
+        // Do a geometry query.
+        query_geometry(query)
+            .then(result => {
+                console.log("Query result:", result);
+                if (result) {
+                    updateProposal(result);
                 }
             });
     }