GEOG 863:
Web Application Development for Geospatial Professionals

6.2 Querying


One of the most common operations performed in GIS is the query. The Esri JS API makes it possible for developers to query layers in a number different ways. You might set a layer’s definition expression so that it displays just a subset of its data. You can also query a layer to get a count of features meeting the criteria, to get the IDs of the features, or to get the features (attributes & geometries) themselves.