Digital Geography

Creating ARCs in QGIS: The Python Way

So I came across this nice little project which focussed on trip planning and route over large distances… And there was this nice little post from Nathan Yau at flowingdata.com where he describes the making of great circles from one point to different other points in R and the other example from Anita Graser where she shows how to deal with an Arc in QGIS but using postgis functionality. So what about QGIS itself and a programmatic way? See yourself…

Python in QGIS and ArcGIS: A Small Example

Often the usage of GIS never touches the world of programming and I think a lot of GIS users today feel fine with using simple tools and try to avoid tools like Python for their daily work. Despite any prejudices regarding programming, Python can be a big help in your basic tasks and is a very easy scripting language to learn. So let us check out Python in ArcGIS and QGIS with a buffer analysis as an easy example. Nevertheless I recommend to take some coding lessons in Python using CodeAcademy.

reproject and filetype change in python/pyqgis for QGIS plugin

In my current work on the qgis2leaf plugin I had the idea to place raster data on a leaflet map as an image overlay. With this in mind and looking at a webmap I needed to consider a good filesize, a strict projection of EPSG:4326 and a strict filetype as well. So decision was: projecting everythin to EPSG:4326 and changing file type to *.jpg. I know, how to do this in the Terminal and in QGIS. But what options do you have using python/ pyqgis only? Terminal For doing this work in the terminal/shell/command line the one and only choice…

How to build your own QGIS plugin

Since I’ve created the QGIS plugin qgis2leaf I was surprised how easy it is to create a plugin for QGIS. In this post I would like to show you how to build a basic buffer-plugin and give some tips for debugging and developing. the plugin template QGIS plugins are competely build in Python: the UI can be designed with QT designer using PyQT. The whole logic of the plugin needs to be written in Python as well. But lets be honest: It would be great if you would have  a starting point. In QGIS there is a plugin for this called…