Retrieving Data

After loading and analyzing data, you can export it back as GeoJSON for rendering or as plain arrays for charts and tables.

Get a Layer as GeoJSON

getLayer returns a FeatureCollection ready to pass to autk-map:

const geojson = await db.getLayer('buildings');
map.loadGeoJsonLayer('buildings', geojson, LayerType.AUTK_OSM_BUILDINGS);

The returned FeatureCollection includes a bbox property. If OSM data is loaded, the OSM bounding box is used; otherwise, the layer's own bounding box is computed.

Get Raw Table Data

getTableData returns the rows of any table as plain JavaScript objects. It works with layer tables, CSV tables, and JSON tables alike:

const result = await db.getTableData({ tableName: 'incidents' });
// result.data: Array<Record<string, unknown>>

Use pagination for large tables:

const page = await db.getTableData({
  tableName: 'incidents',
  limit: 100,
  offset: 200,
});

Get Bounding Boxes

OSM bounding box — the geographic extent of the loaded OSM area:

const bbox = db.getOsmBoundingBox();
// [minLon, minLat, maxLon, maxLat] or null

Layer bounding box — computed from the geometry of any layer:

const bbox = await db.getBoundingBoxFromLayer('neighborhoods');
// { minLon, minLat, maxLon, maxLat }

List All Layer Tables

getLayerTables returns only the tables that contain geometry (OSM layers, GeoJSON layers):

const layers = db.getLayerTables();
// Useful for iterating and passing each layer to autk-map

for (const layer of layers) {
  const geojson = await db.getLayer(layer.name);
  map.loadGeoJsonLayer(layer.name, geojson, layer.type as LayerType);
}