Archive for the ‘programming’ Category
A 10 Minute Intro on using BitBucket with Windows
There are already a couple of official quick start guides to using Mercurial’s Window’s client program TortoiseHG, but below are the bare details of how to use it with a new account on the BitBucket service.
Source Control using BitBucket
Putting code under source control is on most checklists for modern software development. Even small side projects, scripts, and code snippets can benefit from being under source control. For example:
When you improve the code others can see the changes and get the benefits- If someone else improves the code those improvements can be passed back to you via an automated process
BitBucket is a hosting service for the code-source control system Mercurial. Mecurial is part of a new-wave of distributed source control systems that have the following advantages and disadvantages over regular non-distributed source control:
Stack Overflow & OSGeo
Stack Overflow, as most developers will already know, is a question and answer site for programmers. It’s perfect for mainstream development questions in any programming language, and has also become the support site of choice for some newer programming communities such as Android developers. 
It can also be used as a barometer to see which current open source GIS projects have gained traction in the mainstream programming world. I took the full list of OSGeo projects from http://www.osgeo.org/ and ran queries on the site to see how many questions there were for each project. The results are as follows (as of May 2010):
Setting up Visual Studio 2008 for Compiling 64-bit DLLs
This step should be simple. Run the Visual Studio 2008 SetUp program and check the “X64 Compilers and Tools” option under Visual C++
Logging OpenLayers with Firebug
I take it as given that anyone developing with Firefox and OpenLayers has Firebug installed. Firebug has a number of powerful tools that can make the previous nightmare of JavaScript debugging tolerable.
One feature I recently “discovered” are the logging options. It’s definitely a timesaver over my previous method of putting temporary alert(vals); throughout my code. As well as debugging the logging is very useful for automatically documenting formulae in JavaScript with worked examples that can then be pasted straight into the documentation.
An example of the logging capabilities can be seen on my sample OpenLayers page. If you already have Firebug installed you should be able to see the output similar to that below when the page loads.
Read the rest of this entry »
The Seven Bridges of Königsberg
..or do geodevelopers require mathematics?
Alan Skorkin has a great post on “you don’t need math skills to be a good developer but you do need them to be a great one.” Geo-technology developers have similar requirements, and the majority of GISs revolve around CRUD operations. However due to the nature of spatial data we occasionally get to meddle in the world’s of projections, geometry, typology, and set theory more than our counterparts in other sectors.
The Ancient Mysteries
Whilst concentrating on algorithms and recursion is a definite benefit to all developers, us spatial developers need a few more specific tricks. Euler’s 1736 paper on Seven Bridges of Königsberg is one of the first academic writings on modern topology. The titles of these mathematics puzzles create an aura of mysteriousness and arcane knowledge that definitely sweetens the somewhat dour algebra underneath.
The solution (or non-solution) to this problem underpins many of the more advanced techniques used by GIS packages today. The “Travelling Salesman”, whilst conjuring up less interesting images, relies on similar principles of graph theory. Read the rest of this entry »
6 Tips for Developers Moving into GIS
With the rise of the neogeographers, along with the increased awareness and use of GIS thanks to the web, more and more positions are open for developers looking to move away from writing business accounting logic, and into the exciting “new” world of spatial data. I’ve noticed a few gotchas that have happened to developers with no GIS background while working on projects, so this list may at least raise awareness of some of the hurdles.
1. Get to Know your GIS Application
Most desktop development in GIS involves building extensions to an existing application using an existing programming library. In order to avoid reinventing the wheel you need to be able to use your GIS desktop package.
Before developing any automated tasks, manually go through the process to get a feel for any issues that may arise, and learn some of the terminology used by the program for the various functions. If the application has an option for hatched polygon fills, this option is also likely to be buried somewhere in the API. If you can’t find what you are looking for then run what you are trying to accomplish past a GIS user.