More about fTools

09.08.2012 11:33 ·  GIS  ·  qgis, ftools, processing

Reviewed 19 fTools tools in two groups: cleaned up the code, fixed some bugs, optimised a bit. There is still as much to do. Then test and if no critical bugs appear, I will commit.

fTools and SEXTANTE

01.08.2012 14:23 ·  GIS  ·  qgis, ftools, processing

SEXTANTE will soon become part of QGIS: the code freeze in the old repository and the migration are scheduled for 20th August. After the migration, only the Java-related part will remain in the old repository, while QGIS will get a new core plugin.

In this context, I have decided to revise the fTools provider code, synchronise it with the original utilities, and generally prepare for migration and code removal in any way possible. I will be happy if someone helps with testing and is willing to publish plugin package with the latest fixes.

Welcome to the development team

25.07.2012 17:12 ·  GIS, Notes  ·  qgis, processing

Four patches + an elegant solution to a problem, and… I became a full member of the development team of the SEXTANTE project.

Geotag and Import Photos plugin

20.07.2012 19:09 ·  GIS  ·  qgis, plugins

One type of data used in GIS is geotagged photos, i.e., photos whose metadata includes the coordinates of the location where the photo was taken. But there are not many tools for working with such photos in QGIS: all that comes to mind are eVis, photo2shape and its little-known ideological parent, ImagesToShape. In principle, these two modules are sufficient for many tasks. You can use photo2shape to map the locations of photos and use eVis to view geotagged photos and link them or other documents to features of a vector layer. Sooner or later, however, a task will arise for which the capabilities of the existing tools are not sufficient.

Geotag and Import Photos is a new QGIS plugin developed for NaturalGIS. It allows you to process geotagged photos, geotag them and create a point shapefile from them.

Key features:

• batch geotagging photos using a point shapefile or manually defined coordinates
• add custom tags and/or modify existing tags in batch mode
• create a point shapefile with a fully customisable list of attributes from a set of geotagged photos
• ability to append data to an existing shapefile

QGIS is 10 years old

18.07.2012 21:00 ·  GIS  ·  qgis

Today, 19 July, Quantum GIS celebrates its 10th birthday. Over the years, QGIS has grown from a simple PostGIS data viewer developed by one person to a full-featured, extensible, cross-platform desktop GIS with support for multiple data formats, extensive analysis and design capabilities, which is developed by programmers from around the world and used successfully by individuals and organisations.

I suggest we remember how it all started.

TauDEM in QGIS

29.06.2012 18:35 ·  GIS  ·  qgis, plugins, processing

There is a software called TauDEM (Terrain Analysis Using Digital Elevation Models). It provides a free (GNU GPL v2) set of tools for extracting and analysing hydrological information from digital elevation models. TauDEM is developed by David Tarboton of the Water Research Laboratory at Utah State University.

The tools are written in C++, are cross-platform, and have a console interface. Users of ArcGIS 9.3.1 and 10.0 can install an add-on that allows them to run the tools from ArcToolbox using simple dialogs. For others, the only way to use TauDEM is the “scary” command line.

Recently, QGIS also got a powerful and convenient framework that allows easy integration of various tools and libraries (yes, I’m talking about SEXTANTE). Thanks to this framework, QGIS users who need hydrology tools now have a way to use TauDEM directly from QGIS.

Of course, you need to have TauDEM installed in order to use the plugin. While the installation on Windows is quite simple (there are compiled files and detailed installation instructions on the site), Linux users will have to build TauDEM themselves.

QGIS 1.8 "Lisboa"

21.06.2012 09:29 ·  GIS  ·  qgis, release

Almost a year has passed since the release of QGIS 1.7.0 “Wrocław”. It was supposed to be the last release of the 1.x branch, but time has taken its toll. The developers simply do not have enough resources to maintain several branches simultaneously, so it was decided to abandon the division into “stable” and “development” branches. All future releases will be based on the master branch. The result of these revised plans is the release of QGIS 1.8.0 “Lisboa” today.

This release contains many bug fixes and a significant number of new features. In addition, QGIS 1.8.0 has some minor API changes that affect the print composer. If you are using this part of the API in your plugin and are experiencing problems, the developers will be happy to help you adapt your code.

You can find a detailed description of the new features in the official announcement. I will only mention the most interesting ones:

• QGIS Browser is both a standalone application and a dockable panel within QGIS. It simplifies navigation through the file system and connected data sources (PostGIS, WMS, WFS…), allows you to view metadata and preview data, add layers to the map using drag and drop
• DB Manager is a new database management plugin. It supports PostgreSQL/PostGIS and SQLite/SpatiaLite, support for other databases can easily be added if needed. The plugin allows you to view tables (including those containing spatial information), add tables to a map or import layers from other data sources into the database, run queries, and display the results as layers
• Heatmap plugin — a new core plugin for creating raster heat maps from point vector data
• the functionality of the Terrain Analysis plugin has been updated and extended: in addition to calculating slope, exposure, and roughness index, the ability to create shaded and colour relief maps has been added
• interface customisation tool — a dialogue that allows you to hide different parts of the QGIS interface (panels, buttons, widgets…)
• reorganisation of plugins — new menus “Vector”, “Raster”, “Internet”, “Database” have been added. All core plugins and some third-party plugins have been updated and now create their own menus in the corresponding top-level menus
• MSSQL Spatial support — added a new data provider to connect to Microsoft SQL Server spatial tables
• support for compressed datasets — transparent opening of raster and vector data from zip/gzip archives
• two new tools in the “Vector” menu: “Densify geometries” and “Create spatial index”
• “Export/add geometry column” tool can perform calculations on an ellipsoid and in the layer or project CRS
• and much more

How to open CSV files in QGIS

30.05.2012 18:51 ·  GIS  ·  qgis, howto

Recently, there have been a lot of questions about working with CSV files in QGIS. So here is my attempt to shed some light on this complex and confusing topic. Be prepared for a longread.

Statist 1.0

14.05.2012 16:46 ·  GIS  ·  qgis, plugins, statist

Statist. My first plugin for QGIS. That was a long time ago: 2009, QGIS 1.0.0, start of discussions about including fTools in the core (yes, fTools was a regular plugin that had to be installed manually), only a few third-party plugins, and almost no instructions on how to write Python plugins… And I was younger and didn’t know much (to be fair, I still have a lot to learn).

The last major update of the plugin was also in 2009: I was happy with the functionality, and there were no critical bugs. Later, as I gained knowledge and experience, I thought about refactoring several times, but it didn’t work out. And recently, something came over me, so I sat down and did it.

Users will probably not notice any difference, as there are not that many changes visible to them: only support for getting statistics on joined fields has been added. But there are many more changes under the hood:

• the code to check for the presence of matplotlib has been rewritten
• new signal-slot connection syntax is used
• completely rewritten code for calculating statistics
• unused and duplicate code was removed and classes were moved into separate files
• system font is used for histogram labels

The plugin now lives in my repository, please report bugs and feature requests by mail or in the bugtracker (preferred).

Again about SEXTANTE for QGIS

24.04.2012 11:07 ·  Notes  ·  qgis, plugins, processing

I found out how to write plugins for SEXTANTE. It turns out there is nothing difficult about it, and SEXTANTE is great. It is a pleasure to write plugins for it. I started by adapting my first plugin, Statist, and now I’m thinking about porting all the other analytical plugins. And if all goes well, I will have my own toolbox with the modest name “Alex’s tools” :-).