Slashgeo posts on the release of the latest version of the open source GIS, Quantum GIS; this is version 0.10, code-named “Io”. There’s a press release describing the new features, with screenshots. The vector editing capabilities in particular seem to have gotten a major boost in functionality, but there are other improvements as well (default style layers, better raster control, in-application browsing/installation of Python plugins). I look forward to giving it a spin.
Archive for the 'GIS' Category Page 2 of 12
If you regularly work with bearing and distance from a coordinate position, you might find Forward/Inverse a useful tool. Just enter the starting position (latitude/longitude), the bearing and distance to the destination, click Calculate, and get the coordinates of the destination:
In this example, the distance is in kilometers, and the bearing in degrees, but you can customize those units: degrees or grads for angle, and a full range of English and metric units for distance. You have the choice of 26 different ellipsoids, and a selectable lat/long format (decimal degrees, DM, DMS).
You can also capture the results in a text file, useful if you have a list of them to calculate. The Cycle option is especially useful in such a case, as it puts the destination coordinates (2nd Station) automatically into the origin coordinates (1st Station). So, you can continually input azimuths and distances, calculate the next destination, make that the new “1st Station” with the Cycle button, and capture all the data for all points in a text file. Finally, if you choose “Inverse” under the Direction menu, you can calculate the azimuth and distance from the 1st station to the second one.
This has been around for a while, but I’ve just gotten to it. Metacarta Labs’ Map Rectifier lets you georeference/register an uploaded image file to geographic coordinates/WGS84 using data from a variety of sources. Default data layers, selected by clicking on the “+” sign in the right map window, include:
- OpenLayers WMS
- OpenStreetMap
- Satellite
- TIGER
- Google Maps (roads)
- Google Maps (satellite)
But you can add layers from any WMS server. The process is incredibly straightforward. Upload your map image to Map Rectifier, and it will appear in its own window:
Add control points as markers on one side by double-clicking, then add them to the corresponding point in the data layer on the other side:
Double-click on an existing marker to move it to your desired point; the table on the left keeps track of the Ground Control Points and the estimated error. Select your warping method (Best Fit, Linear, Quadratic, Cubic, Thin Spline), then click the “Warp” button. You can display the warped map on top of the reference image as a semi-transparent overlay. Download a GeoTiff or JPEG2000 file of the registered image in geographic/WGS84 projection, or get a URL for a WMS. Uploaded images are publicly available, so don’t upload anything you wouldn’t want someone else to see. Final accuracy will depend on the accuracy of the registered image, which can vary. Still, very slick. There’s supposedly a more advanced version under development.
On her blog, Jo Cook of Oxford Archaeology has the sad tale of what happens when a proprietary GIS company changes their licensing terms, making it too financially onerous to continue using their software. In the comments, Stefan Steiniger links to his useful tables comparing the features of many open-source GIS programs (most of which I mentioned in my recent series of posts). He has overview and functionality web pages, and also downloadable Word versions.
The final part of the series. Part One, Part Two, Part Three. All parts will be regularly updated as more programs come to my attention.
SAGA
Type: Freeware, open-source
Platform: Windows, Linux
Last update: 2007
Personal experience: Medium
Continue reading ‘The Big List Of Free GIS Programs - S Through Z’
Part three of this series (part one, part two).
Natural Resources Database (NRDB)
Type: Freeware, open-source
Platform: Windows
Last update: 2007
Personal experience: Minimal
Description
Continue reading ‘The Big List Of Free GIS Programs - N Through R’
A continuation of this list from the first post.
Integrated Land and Water Information System (ILWIS)
Type: Freeware (formerly commercial), open-source
Platform: Windows
Last update: 2006?
Personal experience: Minimal
I plan to look at this one in greater detail in the future - looks like it has some really useful capabilities. Here’s a list of chapter titles from the Applications Guide to give you a feeling for what it can do:
Continue reading ‘The Big List Of Free GIS Programs - I Through M’
The backlog of topics for this blog continues to grow beyond my ability to keep up with it, and current work demands make it unlikely I’ll be able to catch up soon (though I should still be able to put up new posts at about the same rate). So I thought I’d do a quick set of posts on various types of GIS software, including both those that I have looked at in some detail, as well as those that I’ve given either a cursory look, or none at all. Let me know which ones I’ve missed, and I’ll add them to the list (and put up a separate post on them if warranted). I welcome comments on any of these programs, especially those I haven’t really posted on yet; if the comment is long enough, I’ll put it up as a full guest post. And I’m likely to come back to some of these in greater detail in the future.
Continue reading ‘The Big List Of Free Basic GIS Programs - A Through H’
