Saving layer styles to your Spatialite database

Just discovered this option in QGIS to save styles for Spatialite layers to the Spatialite database. I don’t know when this option was introduced (I am running the development version at the moment), but I am happy I found it. Continue reading “Saving layer styles to your Spatialite database”


Extract X and Y coordinates from a spatial table in Spatialite

A quick note on adding two columns with X and Y values in a vector layer in spatialite. Spatialite stores the information about the geometry in binary format in the ‘Geometry’ field.

You can use the Spatialite function AsText() to convert and extract these values as a Well Known Text (WKT), which is an easy to read format. If you for example have a spatial table ‘Waypoints’ with two columns ‘PKUID’ and ‘Geometry’, you can extract a column with WKT values using: Continue reading “Extract X and Y coordinates from a spatial table in Spatialite”

Split strings in SQLite

I am just back from vegetation survey in Kenya and Uganda. Before starting with the analysis, I will have to go through the more boring data entry and organization. I will use a Spatialite database to store all the data as it plays nicely together with QGIS as well as R. For example, importing the waypoint data (gpx format) into a spatialite database is a breeze with the QSpatialite plugin for QGIS.

One problem is that data and time in the gpx file are given in one field, in the form ‘2011/11/01 5:49:41+00‘. There are various ways I could split this before importing in the SQLite database, e.g., using R or a spreadsheet. But how to do this after importing the data in the Spatialite database? The date + time are imported in the field ‘time‘. Continue reading “Split strings in SQLite”