I have found that Google does a good job with generic data but often a company needs to display their GIS data on a Google Map.  This is often the case when the general public is viewing the data and doesn't want to learn how a 'heavy' IMS website works.  In this case, I often suggest a Google Map Mashup using a WMS.

The Mashup gives us a few great features:

• Ease of use
• Speed of deployment
• Capacity to scale (if using a cache of generated tiles)

You'll need a few things to get started:

1. A place to host the website (this can be 'localhost' if you are developing and testing on the same machine)
2. A working WMS (I assume you have one of these if you are trying to create a mashup.)
3. A Google Map API key
4. A Snippet of code that helps generate the request to the WMS (Found Here).

I have attached a simple example that you will need to put on your server and change the WMS layers.

WMS_Google_Mashup.txt (2.72 kb)

I recently began working with SQL 2008 Spatial tools to build a Google Maps Mashup that was part of a larger work order management system for a land surveying company.  The ease of going from SQL to the Google API made it a breeze.

I had a few requirements:

1. Dynamically place markers on the map based on database critera.
2. Color those markers according to the values for each record in the database.
3. Create a visually appealing map.
4. Be fast.  My primary users are on a limited 400kbps DSL connection so speed is everything.

First, I used Manifold GIS software to get my data ready for use. This included moving the data into a SQL 2008 DB out of SHP file.  We chose Manifold GIS for a few reasons.  Mostly price, then also the great number of data formats that it can open and save as.

Second, I wrote a ASP page that ran on the server that accepted the bounding box of an area and then return a delemited list of results with Lat,Lon along with other attribute data.  This is very simlilar to a WFS but greatly trimmed down.

Third, I wrote a Javascript HttpXmlRequest function that would get the getBounds() function from the Google Map API and pass it to the script described in the second step.  Upon the ASP script returning a list, the Javascript would parse this list and place markers at appropriate locations on the map.

Code Samples:

1. GIS Code
2. ASP Code
3. JS Code