Category Archives: Spatialite

QGIS fighting bugs

Real bugs, agricultural pests, cause damages to food production throughout the world. GIS techniques can help in monitoring pest infestation by collecting and mapping data from traps, baited with pheromone lures. QGIS when teamed up with Spatialite makes the ideal combination for pest control programs to maintain and display the distribution of different species of insects. Here’s how it’s done. Continue reading QGIS fighting bugs

Spatialite helps creating an index of LIDAR tiles

We have a large set of LIDAR data, in separate *.las file, each covering a small rectangular area. I wanted to create a polygon shapefile of the coverage of each tile for reference so I know which files to choose when we need a subset of the whole region. Using a bash “one-liner” and a simple function in Spatialite I had my polygon layer.
Continue reading Spatialite helps creating an index of LIDAR tiles

Spatialite: Speedup your query with spatial indexing

Spatialite, like any good spatial data management system, can build a spatial index for your layers. Using this index in your spatial queries will dramatically shorten the runtime for that query. The latest version of Spatialite offers a nice compact format for using a spatial index. To demonstrate, I created a point layer of 20,000 theoretical store locations, with sales data for each store, and a polygon layer of over 280 “local councils”. My mission it to sum up the total sales in each local council. So I need to find which stores are located in each local council and aggregate sales for those stores.
Continue reading Spatialite: Speedup your query with spatial indexing