The QGIS Community Team proudly presents three new QGIS user reports aka Case Studies:

“Working with QGIS in a spatial data infrastructure of Jalisco in Mexico” by Carlos Ruiz

“… I realized that QGIS was the only one which can connect to WMS, WCS and WFS successfully.”

“Quantum GIS and GRASS in Biogeographical Research in Spain” by Marcia Barbosa

“I found that QGIS provided a very intuitive interface for GRASS, hat they complemented each other perfectly, and they provided all the analytical capabilities I needed.”

“QGIS – an interesting instrument for forestry planning concepts at local and regional level in Switzerland” by Raphael Häner

“The most important qualities of QGIS are the intuitive user interface and the compatibility with different file formats. It is an ideal tool for projects that are on one hand based on existing geographic data and on the other hand require the acquisition of new data.”

If you would like to share your own story, just contact the QGIS community team. All contributions welcome!

Release of QGIS 1.5 Announced

By underdark

2010-07-31

GIS, QGIS

The QGIS developer team has just announced the release of QGIS 1.5. Check the official visual change log featuring a list of the most prominent changes and many screen shots.

gis.stackexchange.com Now in Public Beta!

By underdark

2010-07-30

GIS

gis.stackexchange.com is now in public beta. Join the community to learn and/or share GIS knowledge.

Right now, gis.stackexchange.com has 329 users and 395 questions have been asked (92 % answered). The page has only been online for a week now, but the community is growing fast.

Join now and help us advertise this new community page!

Customized Attribute Editing in QGIS 1.5

By underdark

2010-07-28

QGIS

1 Comment

QGIS 1.5 Attribute Edit Dialog

Creating new datasets can be a tedious task. To make things easier, QGIS enables users to customize the editing dialogue.

Users can choose from one of the following editing widgets:

Line edit <default> – a simple edit box
Classification – displays a combo box with the values used for “unique value” classification (symbology tab)
Range – allows numeric values within a given range, the widget can be either slider or spin box
Unique values
- editable – displays a line edit widget with auto-completion suggesting values already used in the attribute table
- not editable – displays a combo box with already used values
File name – adds a file chooser dialog
Value map – shows a combo box with predefined description/value items
Enumeration <postgres only> – a combo box with values that can be used within the columns type
Immutable – read-only
Hidden – makes the attribute invisible for the user
Checkbox – a checkbox with customizable representation for both checked and unchecked state
Text edit – an edit box that allow multiple input lines
Calendar – a calendar widget to input dates

Data Defined Labeling in QGIS

By underdark

2010-07-28

QGIS

A useful and powerful way to define layer symbology and labels is using data-defined properties. While many of the options are self-explanatory, others require knowledge about the valid options.

Note: These options are currently only available for the “old” labeling under “Advanced” tab.

Position

Valid options are: left, right, bottom, top, bottom_left, bottom_right, top_left, top_right

Color

I successfully used the color names red, blue, green, black, yellow, and orange. Alternatively, you can enter color hex-codes: red = #ff0000

PostGIS 1.5 Cheatsheet and Comparison

By underdark

2010-07-21

GIS, PostGIS

BostonGIS has compiled a great cheatsheet for PostGIS 1.5. You’ll find both a web version and a PDF version here: http://www.bostongis.com/postgis_quickguide.bqg.

Additionally, they have published an extensive comparison of SQL Server 2008 R2, Oracle 11G R2, and PostgreSQL/PostGIS 1.5 spatial features: http://www.bostongis.com/PrinterFriendly.aspx?content_name=sqlserver2008r2_oracle11gr2_postgis15_compare.

How to Calculate Weighted Average Position

By underdark

2010-07-21

GIS

The weighted average position of a point cloud can sometimes be more useful than the ordinary average position, especially if there are outliers in the data. The maths behind it is relatively simple:

w ... weight
sum(d) ... sum of distances between the weighted point and all other points
p(w) ... weighted average position

w = 1 / sum(d)

p(w) = (p1*w1 + p2*w2 + ... + pn*wn) / (w1 + w2 + ... + wn)

You’ll only need a function that calculates all distances like in QGIS – fTools – Distance Matrix.

If you know any GIS implementing this function, please post them.

FOSSGIS2011 Location announced

By underdark

2010-07-20

GIS

FOSSGIS2011 is going to take place from 5th to 7th April 2011 in Heidelberg, Germany. More information can be found on the conference wiki: http://www.fossgis.de/konferenz/wiki/Main_Page/2011.

You can check this year’s program on http://www.fossgis.de/konferenz/2010/index.de.html.

Stack Exchange on Geographic Information Systems

By underdark

2010-07-14

GIS

gis.stackexchange.com (not live yet) could soon be the new Q&A site for anyone interested in GIS. The technology is based on Stack Overflow, meaning that users can rate answers to the questions so that the best one shows up first. If you would like to see this happen, support the proposal here: http://area51.stackexchange.com/proposals/1425/geographic-information-systems?referrer=gnmvpv_s0afgMMEpzVsZAg2.

Update: gis.stackexchange.com is now in Private Beta!

QGIS SpatiaLite Manager

By underdark

2010-07-12

QGIS, SpatiaLite

3 Comments

SpatiaLite Manager connected to example database (additional data from Natural Earth)

SpatiaLite Manager is a plugin for QGIS for managing spatial data in SpatiaLite databases. It’s based on the PostGIS Manager plugin that provides equal functionality for PostGIS.

In the database view, all tables are listed and it’s easy to distinguish between tables, views and spatial tables of different geometry types. On the right, different tabs show table meta data, table and a map preview for geometry tables.

Additionally, there is an SQL window that allows execution of statements from inside QGIS.

While there’s certainly room for additional functions, this is a great start and facilitates working with SpatiaLite databases considerably. Possible enhancements could be: