GeoMusings

Or vice versa.

A while back I posted about setting up a GIS server using open source GIS technologies. When I left off, I was going to start messing with SharpMap. I’ve been able to get back to that recently. I am working on a project where I need to do some basic spatial operations on a workstation but I want to keep a relatively small software foot print on the box. Of course, this screams “web service” or some such thing but the platform is mobile with no guaranteed network access.

So I went back to SharpMap. It’s footprint is relatively small (compared to ArcGIS) and the licensing model can’t be beat . Next, I had to focus on the data source. I decided to look at SQLite due to its small footprint. Additionally, the availabiliy of an OLEDB driver gave me option for non-spatial data that shapefiles alone didn’t (I just didn’t want to wrestle with the dBase driver).

So I got to do something I’ve wanted to do for a while: write my own data provider for SharpMap. There’s probably something out there already but how can I learn that way? So I based my data provider class on the class that already existed for MS SQL Server (MsSql.cs). It served as an excellent basis. I was surprised at how very easy it was to do this sort of implementation. The picture below depicts a SharpMap MapImage control with polygon data being read from SQLite.

SQLite is inherently text-based so I found it easier to store the geometry as WKT rather that WKB but that actually helps me with another project requirement: displaying the data in a WPF form. Transforming the WKT to XAML will be easier but I digress.

I am very impressed with the updates being made to SharpMap. I feel like I’m just scratching the surface of what it can do. Version 2.0 has not technically been released but I have found the latest builds to be very stable and I’m moving forward without hesitation using it in my project.

I have uploaded my code below. Just rename it to a .cs file.

Click here for the SqlLite.cs source code