The choice for a GIS is very important for our kind of project. It is one of the most important pieces of a VTS. In fact, that is the emerged part of the software, the one that will be evaluated by people who consider Free VTS as a choice.
People who want a VTS or a new VTS are invevitably influenced by everythings that they see or used all around them. Now a VTS must have a way to be consulted or controled by a web browser, it means something that can run on PC or a mobile phone. It should probably be able to stored data on the cloud in order to share with another instance of a harbour or a client, etc.
The technologies involved in these kinds of operations must be capable of delivering the requested product without needing to reinvent the wheel for each particularity of the application and cutting edge technologies must be considered to fill these requirement.
Two opensourced GIS seems to meets our requirement and they are SharpMap and DotSpatial. Both are product that can be used in a Windows environment that is the most used plateform for a VTS. Both used C# for programming language and can be used on a windowed application or an ASP.NET project. This seems to meets our requirement about a VTS that can be used on a PC and that are web enabled. There are obvioulsly other ways to build and use the VTS with web and windowing system but we think that reusing the same code to do both work would be a good idea rather than multiplying the technologies and efforts.
So we tried a bit both Sharpmap and DotSpatial and our choice. SharpMap seems more appropriate for our project, although we initially condidered DotSpatial at the start and for quite a while during our testing.
Considering the age and numbere of contributions for the project, DotSpatial seems at first sight a project more alive than SharpMap. However, the lack of documentation and poor quality prevented us from pursuig more sophisticated tests with this GIS.
On the other hand, the SharpMap project has a branch for a 2.0 version. Probably that at some point in time, all further development of this project will be make in this branch. In any case, we fopund that SharpMap seemed to fit very well for our requirements and we were able to do the tests we washarnted with this technology as it is now.
Our final choice was therefore SharpMap as GIS for the project Free VTS and it is wity this technology that we will build the cartographic side of the display for this VTS.