Practical GIS

Saving queries

As we've already witnessed, using PostGIS has a great advantage of offering flexible results over traditional desktop GIS applications. That is, we can play with queries without filling the memory or disk with useless intermediate data showing wrong results. But how can we save the correct results once we've found out the right query to produce it? There are various ways of saving results in PostgreSQL. The most basic way is to save them right into a new table. All we have to do is to prefix our query with the CREATE TABLE tablename AS expression.

Let's try it out by creating another curve table with the following expression:

    CREATE TABLE spatial.tempcurve AS SELECT id,     CreateCurve(geom) AS geom FROM spatial.waterways;