Practical GIS

GeoJSON

The last format that we'll now discuss is the GIS data exchange standard built upon the famous JavaScript exchange format--JSON (JavaScript Object Notation). GeoJSON is a very permissive format inheriting the object-oriented nature of JavaScript. Type and shape consistency is not required in the format; we can have as many attribute types in a column and as many geometry types in a layer as we want. By definition, the permitted types are integer, floating-point number, text, boolean, null, array, and object. The permitted geometry types are point, line, polygon, and their multipart versions. Let's export our filtered GeoNames layer to GeoJSON.

As we can see, the result is much more concise than the markup languages but we can still ...