Nathan from woostuff.wordpress.com has compiled a descriptive comparison of MapInfo and QGIS. He presents the up and downsides of QGIS compared to one of the major commercial GIS around.
A Comparison of MapInfo and QGIS
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More QGIS Case Studies
The QGIS community presents two new case studies:
QGIS and GRASS applied to paleontological survey in Western Portugal by André Mano
QGIS as major GIS software in the Laboratory on Experimental and Applied Geography by Jakub Trojan
Layers from SQL Query with Geoserver 2.1
GeoServer has always been good at simply publishing database tables. But anything more complex (e.g. pre-filtering data in a table, joining two tables together, or generating values on the fly) could be painful. With Geoserver 2.1 one can finally create a layer directly from an SQL query.
"Create New SQL View" interface
Even dynamic queries are possible, e.g.
select gid, state_name, the_geom from pgstates where persons between %low% and %high%
To select for example all states with 2 to 5 millions inhabitants, the following parameters can be added to the normal GetMap request:
&viewparams=low:2000000;high:5000000
Find more information on SQL layers in Geoserver 2.1 documentation.
QGIS goes 3D with the OsgEarth Globe Plugin
Globe plugin had it’s first big presentation at FOSS4G 2010:
(This video is part of a series of videos titled “Comparison of Open Source Virtual Globes”.)
Where to download Globe plugin
The globe plugin is a C++ plugin based on the threading branch and can be
downloaded from
http://github.com/sourcepole/qgis/tree/threading-globe
How to install QGIS Globe
To install Globe plugin, you can use Marco Bernasocchi’s install script. Thanks Marco!
Sourcepole (the developers of Globe plugin) promise that as soon as the threading branch is merged into trunk, globe should make its way into trunk as well.
Creating High-Resolution Images Using QGIS
Creating high-resolution output with QGIS can be tricky. “Save as image” saves the current map extent and creates a world file, but the output size cannot be specified directly. It simply saves the currently visible map. Most of the time this resolution will not be satisfactory.
Using “Print Composer” enables you to create full-grown maps including legend, scale bar, text annotations, north arrow, attribute table, decorations, etc. You are free to chose any size/resolution for the output image. Unfortunately, this way you will not get a world file.
That’s where the third possibility comes in handy: Using QGIS from command line to create a snapshot of a map. This way, you can create images of any size and with corresponding world file. The work-flow can be divided into the following steps:
- Create and design your project: Add layers and styles.
- Zoom to the desired zoom level.
- Write down the extent of the map window. Use coordinates in the project’s projection. (You can skip this step and don’t specify –extent option. The project will be restored in it’s original saved state if you do so.)
- Close the project
- Go to command line and run
C:\...>qgis --project myproject.qgs --snapshot image.png
--width 1500 --height 1000 --extent xmin,ymin,xmax,ymax
QGIS will start, load the project, create the snapshot, and close again. That’s it!
Things to be aware of: QGIS will start, load the project, set the given extent (if specified), enlarge the map canvas and then take the snapshot. As a consequence, the extent given doesn’t match the extent of the resulting image. The image will have a bigger extent and contain surrounding areas.
Together with the new labeling tools this can be a fast and (semi-)automatic way to create nice looking high-resolution map images and corresponding world files from QGIS projects.
QGIS “Delimited Text Layer” now Supports WKT!
A great enhancement has been added to “Delimited Text” plugin today. It allows the use of a geometry column formatted as well known text (WKT), as an alternative to using x and y columns to define point features.
Requirements
To view a delimited text file as layer, the text file must contain:
- A delimited header row of field names. This must be the first line in the text file.
- The header row must contain an X and Y field or a Well Known Text (WKT) field. These fields can have any name.
- The WKT field must be in standard format.
Example of a valid text file with a WKT field
id|wkt
1|POINT(172.0702250 -43.6031036)
2|POINT(172.0702250 -43.6031036)
3|POINT(172.1543206 -43.5731302)
4|POINT(171.9282585 -43.5493308)
5|POINT(171.8827359 -43.5875983)
Update: Tim has posted a video tutorial: Video tutorial #2: Delimited Text Plugin
QGIS 1.6 Release Announcement
QGIS 1.6 is now officially released. Read the announcement on QGIS blog for information on new features or go directly to the download page.
Update: The QGIS manual has also been brought up-to-date.
QGIS & ECW – A never-ending Story?
ERDAS’ ECW licensing does not allow free redistribution. Therefore, QGIS can’t support .ecw out of the box. However, you can download ERDAS’ SDK – which gives access to .ecw rasters – from their website for free.
If you need ECW support in QGIS and are struggling, you might find Micha Silver’s post “QGIS on Windows with ECW” very helpful.
OSGeo Educational Content Inventory
The OSGeo Education and Curriculum Project provides a knowledge base for everyone interested in working with geoscience in general and open source GIS specifically. Everybody is invited to contribute and upload/link their educational material to the database for the benefit of the community.
The database already contains a number of QGIS related materials, e.g. “GIS Basics with Quantum GIS” by Micha Silver.
QGIS Python Plugins – How to get started
Starting from scratch can be painful. Luckily there’s a tool out there that can help: PyQGIS Plugin Builder. The form will build a minimal plugin for you. You’ll get a ready QGIS 1.0 plugin that implements an empty dialog with Ok and Close buttons. You can find a step-by-step description on how to create and modify this dummy plugin at linfiniti.com – “A simple QGIS python tutorial”.
From there, I suggest moving to the PyQGIS Cookbook – a great resource for everything related to QGIS with Python – especially the part about “Developing Python Plugins”. Tim also created a PDF version of the Cookbook (original post) if you prefer it in hard copy.
Free and Open Source GIS Ramblings 