GIS with Bing Silverlight and SQL 2008?

I have data that I want to create a GIS type application that will have the typical features of adding and removing layers of different types. What is the best architectural approach?

The data consists of property locations in E开发者_如何学Goastings and Northings. I also have ordnance survey data in GML and Shapefiles.

I know this is a very broad question but the subject area also seems very broad to me and I am unsure which direction to go.

I was thinking of using SQL 2008 spatial and Bing Silverlight control to visualise that maps.To do this would I have to convert the eastings and northings to GWS84 geography datatype? But then if I converted the shapefiles to GML and imported all the GML files to sql using GeomFromGML they would be in geometry datatypes. Wouldn’t the two types be incompatible?

Also, should ESRI ArcGIS API for Silverlight feature in the equation? Is this a good environment to create maps that I can point as SQL sqerver 2008 as the datasource (using a WCF service if necessary)?

Any advice greatly appreciated!

This is something I've done several times, using OS data from SQL Server in both Bing Maps AJAX and Silverlight controls. Some general comments below (in no particular order!):

• Don't expect to implement full-blown GIS functionality using Bing Maps. Simple querying, retrieval and display of the data is all fine (+ some simple editing), but after that you'll be struggling with what can be achieved in the browser.
• All vector shapes supplied to Bing Maps need to be in (geography) WGS85 coordinates, EPSG:4326.
• However, all data will be projected and displayed using (projected) Spherical Mercator system, EPSG:3857.
• In terms of vector shapes, you can expect to achieve a similar level of performance as you get in the SSMS spatial results tab - that is, (with careful architecture) you can plot up to about 5,000 features on the map at once, zoom / pan around them, click on them to bring up various properties and attributes etc. However, after that you'll find the UI becomes fairly unresponsive (which I imagine is the reason why the spatial results tabs itself limits you to displaying 5,000 records at once).
• If you want to display more features than this, one approach is to rasterize them by projecting them into the EPSG:3857 projection, creating a .PNG/.JPG image file of the features and then cutting that image into tiles according to the Bing Maps quadkey tile numbering system as explained here:
  http://msdn.microsoft.com/en-us/library/bb259689.aspx and displaying them as a tilelayer. Tile layers are significantly faster than displaying the equivalent vector shapes, although it means the data is static.
• If you do create raster tiles, you can either render them dynamically or pre-render them to improve performance - i.e. you could set up a job to render and update the tileset for slowly-changing data
  every night/every month etc.
• If you're talking about OS Mastermap data, the sheer level of detail involved means that you need to think more carefully about what
  features you want to display, and how you want to display them. Take
  greater London, for example, which covers an area about 50km x 40km. To create raster tiles (each of which are 256px x 256px) at zoom level 19
  covering this area you'd need to render and store 1.3 million separate tiles. If each of those is generated from a database query that takes, say 200ms to run, it's gonna take a looooonggggg time to prepare all your data. Also, once the files have been generated, you might want to think
  about storing them in a DB rather than saving them on a file system.
• As for loading the OS data into SQL Server in the first place - there
  are several tools that will import either from GML or shapefile into SQL Server, and handle the projection from EPSG:27700 (Ordnance Survey
  National Grid) to WGS84 along the way. Try GDAL/OGR or Safe FME for
  starters.

I have a blog at http://alastaira.wordpress.com that has several blog posts that you may find useful describing various aspects of integrating Bing Maps and SQL Server. Particularly, you might want to look at:

http://alastaira.wordpress.com/2011/02/16/loading-ordnance-survey-open-data-into-sql-server-2008/

http://alastaira.wordpress.com/2011/01/23/the-google-maps-bing-maps-spherical-mercator-projection/

http://alastaira.wordpress.com/2011/02/21/using-ogr2ogr-to-convert-reproject-and-load-spatial-data-to-sql-server/