Last update:
Thu Jan 9 20:00:26 2025
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The raster calculator allows you to perform mathematical operations on each cell in a raster. This can be useful for converting and manipulating your rasters. Operators include: Mathematical (+, -, *, /) Trigonometric (sin, cos, tan, asin, acos, atan) Comparison (<, >, =, <=, >=) Logical (AND, OR) To perform operations on a raster or rasters, they must be loaded in QGIS.
Everybody who gets an Eee PC has to write about it–it’s required. I don’t really have much to add to the raft of reviews, except for one small point. I found myself wanting to print something and, based on my last experience, prepared for the ordeal of setting up a printer. I about fell out of the chair when I opened the Printer configuration and found that the Eee had already found the CUPS printer on my network and added it.
I use Linux and OS X as my primary operating systems. Lately I have been using the Powerbook exclusively with ssh or FreeNx to work on the Linux machines on the network. I started off to simply repartition my Powerbook and then reinstall OS X and put Ubuntu on the new partition. That was two days ago. Things are pretty much back to normal now. I have a dual boot system that I can take with me and run my favorite GIS software on both platforms as needed.
Well it was a short summer here. Or perhaps we have defeated global warming. This is the view from the deck on Thursday evening: and this is the view Saturday morning: Of course nearly everyone in the country has removed their snow tires in anticipation of the upcoming May 1 deadline. As they say “Life is tough in the far north”. The good news is that now we can go directly from winter to summer…
An interesting visualization of QGIS development over the last eight years: http://woostuff.wordpress.com/2011/01/03/generating-a-gource-source-commit-history-visualization-for-qgis-quantum-gis/
Marco Hugentobler at the Institute of Cartography, ETH Zurich has announced the QGIS MapServer project. From the website: “QGIS mapserver is a server module for geographic maps. The content of vector and raster datasources (e.g. shapefiles, gml, postgis, wfs, geotiff ) is visualized according to the request parameters. The generated map image is sent back to the client over the internet.” This project is very much in the early stages, as it requires a specific development version of QGIS.
This site aims to bring out some of the latest and sometimes not-so-greatest happenings in the GIS world. We’ll focus to large extent on Open Source software but hopefully mix it up to keep things interesting. We’ll explore things from the new and exciting to the dull and mundane. There are a lot of GIS/Spatial sites out there. Hopefully we can provide some content of interest and you will add this one to those you visit frequently.
There’s been several posts to GIS StackExchange along the lines of: Where’s my .qgis3 folder? Prior to QGIS 3, the .qgis/.qgis2 folder was found under your home directory. At version 3, the folder has moved to a more standard profile location for your operating system. There are a couple of ways to determine where the folder is located: Use the Settings->User Profiles->Open active profile folder menu item Use QgsApplication.qgisSettingsDirPath from Python or the console Here are the “standard” locations for Linux, Mac, and Windows, as found under your HOME directory:
The Script Runner plugin allows you to manage and execute a collection of scripts in QGIS to automate tasks and perform custom processing. Version 0.6 of Script Runner has been released and includes these changes: Arguments can be passed to a script using keyword arguments Script output is logged to the Script Runner window Script output can be logged to disk Preferences dialog allows control of output and logging options Exceptions in scripts are displayed without interfering with console/logging output Context menu (right-click) to access script functions Edit script function uses system default editor or one you specify in preferences For a basic introduction to Script Runner see this post: Script Runner: A Plugin to Run Python Scripts in QGIS
$ uptime 20:20:56 up 434 days, 15:31, 2 users, load average: 2.32, 0.89, 0.53
Do you remember this? If so, you’ve been using QGIS a long time… OGR and PostGIS support No raster support Three widgets on the Symbology tab No symbology in the legend But you could use it handily on a 640x480 display.
Matthew Perry poses the question: Why is the command line a dying art?. Funny how these things go–I was thinking about posting on this same topic just the other day, although I may be repeating myself. The efficiencies of the command line cannot be overstated. I too have seen that deer in the headlights look when a GUI-only user is first exposed to a command prompt. I have also seen people spend days on a data conversion project that could easily be accomplished in hours (or less).
QgisToMapServer converts a saved QGIS project file to a map file, ready to be served with MapServer. A binary preview version for both Mac and Windows is available now. For Linux/Unix users, the source code is available from the Git repository. QgisToMapServer is different from the plugin in QGIS. It is a standalone Python application providing the following features: Create MapServer map files from saved QGIS project files Preview the map file (requires shp2img)
At the ESRI Developer Summit there was news of the File Geodatabase (FGDB) API. Based on the tweets from the summit it appears: The API will be C++ only API works on Windows and Unix/Linux (specifically RedHat, Solaris, SuSE) operating systems Rudimentary support only—features such as annotation, relationships, topologies, etc. are lacking Since ESRI is releasing a targeted API and a not a specification, support for Mac OS X is out of the question.
Here’s a summary of recent additions and updates to plugins in the QGIS repository. FlowMapper (0.1.1) - Generates flow lines between discreet nodes for depicting spatial interaction data (e.g. migration). Query By Example (0.2) - Select features by location. Item Browser (1.6.0) - Browse a multiple selection with auto-zooming to feature and an option to open feature form. Custom Launcher (1.1.0) - Customize your own actions to launch your preferred apps or commands within QGIS.
And so it begins. Chad has made a plea to Microsoft to help sort out issues with the latest World Wind release and Vista. The new security features are causing problems and I suspect that World Wind won’t be the last project to have to deal with it. So far the QGIS project has yet to get an experience report from anybody using Vista. Who knows what that will bring….
Lets face it, GIS systems are complicated. Typically there are multiple servers and applications that make up a “system”. Each of these represent a potential point of failure, thus creating a brittle system. Brittle systems break. The definition of the word brittle is: Brittle: Solid, but liable to break or shatter In other words, we can design solid systems that serve us well, but they can be brittle. We can push on them a bit and they perform well, but push too hard and the whole thing shatters.
The forum (http://forum.qgis.org) has been closed for new registrations and marked read-only. Users have been encouraged to use http://gis.stackexchange.com instead. If you have an thoughts on the closure, good, bad, or otherwise, please comment.
This is a project I have had lingering around for a while. It is a geospatial data browser written in Python using the PyQt and QGIS bindings. It allows you to navigate a tree structure and preview raster and vector datasets. Metadata extracted from the data can be viewed as well. It supports drag and drop for any target that accepts filenames (e.g. QGIS). For screenshots and more, see http://geoapt.com/geoapt-data-browser.
In any sufficiently aged bureaucracy, process overshadows product.
