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Plugins Repository. Time flies when you are having fun!

Plugins Repository

It seems like only yesterday that I was writing about the 14th Hackfest in Gran Canaria. At the end of May 2016, we held the 15th QGIS hackfest! QGIS has been on an incredible journey since the project was started by Gary Sherman 14 years ago, and the fact that the hackfest was held in tandem with the 2nd QGIS International User conference is a testament to the growth and strength of the project. 2nd International QGIS Conference Isn’t it amazing – we just held the second international QGIS User’s Conference! We would like to give a special thank you to the University of Girona’s Director of GIS Service (SIGTE) – Gemma Boix who helped to organised the event as well as ensuring the institutional support for the event. The conference team also extends their thanks to the attendees and presenters, instructors and developers who also actively participated on the event!

State of QGIS The project is in a very healthy state right now. For developers: A Beginner’s Guide to pgRouting. Please read the new instructions for pgRouting 2.0.

A Beginner’s Guide to pgRouting

The aim of this post is to describe the steps necessary to calculate routes with pgRouting. In the end, we’ll visualize the results in QGIS. This guide assumes that you have the following installed and running: Postgres with PostGIS and pgAdminQGIS with PostGIS Manager and RT Sql Layer plugins Installing pgRouting pgRouting can be downloaded from Building from source is covered by pgRouting documentation. Start pgAdmin and create a new database based on your PostGIS template. Creating a routable road network The following description is based on the free road network published by National Land Survey of Finland (NLS) (Update January 2013: Sorry, this dataset has been removed).

First step is to load roads.shp into PostGIS. PgRouting requires each road entry to have a start and an end node id. Next, we create start and end point geometries. (This can take a while.) I recommend adding a spatial index to the resulting table. Advanced Python Field Calculator. Advanced Python field calculator is one of the numerous tools in Sextante for QGIS.

Advanced Python Field Calculator

It’s extremely powerful but it doesn’t use the syntax of QGIS’ default field calculator (the one you can access via attribute table). Therefore, here comes a short introduction: If you want to reproduce this example, I used a dataset of town areas from the new open government data site of Lower Austria. The upper half of the Advanced Python field calculator is rather self-explanatory but the lower half is where it gets interesting: Code in the global expression section will be executed only once before the calculator starts iterating through all the features of the input layer. Therefore, this is the correct place to import necessary modules or to calculate variables that will be used in subsequent calculations. As you can see, the feature geometry can be accessed using $geom. If you want to access an existing attribute, that’s possible using <attribute_name>.

FieldPyculator - калькулятор полей с использованием выражений на Python для QGIS. "Geoscripting" in SEXTANTE. SEXTANTE Spatial Data Processing Framework. PgRouting Project — Open Source Routing Library.


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