Digital Geography

Filter Leaflet Maps with a Slider

If you create maps you always need to ask yourself: how can I make it as easy as possible to read and still have anything I need in my map… or in short: reduction and abstraction. There are different approaches out there when it comes to web maps. Let me show you how to reduce the number of map elements with a slider in leaflet to filter your data interactively.

The Geography of Tweets: Reading Tweets with QGIS

Anita showed some nice examples of tweets in QGIS in 2012. Since then it seemed to be quiet about the twitter-content in QGIS. Yet tweets can be an interesting source of information. Sometimes they can tell you something about the spatiotemporal dimensions regarding a keyword, the digital heartbeat of a defined region and many more. Yet we need to be careful with the data as it is completely biased. But how to get this data stream into QGIS?

CSVs and leaflet: the ultimate ressource

When it comes to certain tasks the usage of leaflet can be tricky. Of course it claims not to be the ultimate webmapping solution but one of the sleekest ones. But when it comes to csv files and reading data from them I always found it hard to implement given solutions listed in the plugins section of leaflet.

create point density raster in QGIS

In some applications you want to calculate the density of points. It sounds very easy and in fact it is using QGIS. Let me show you how. Especially, let me show you how to do this with the heatmap plugin in QGIS. Prerequisities You will need the common installation of QGIS 2.0.1 Dufour and an installed heatmap plugin (see how to install a plugin here). We will use some field data from Indonesia with 500.000 data points. You may download the data (12MB) we will use here. The doing Fire up QGIS and set the CRS of the project according…