One of the most tedious parts of creating any web mapping application is the creation of the base map. The application map data is in many occasions relatively simple points or polygons. Maps are much more useful when we can see not only our map data but also rivers, streams, roads, and aerial photos on our map. Google Maps provides worldwide maps as well as aerial photos utilizing an easy to use interface. All that you need is a web browser and an internet connection. In addition Google provides an API where we can utilize these maps in our own mapping application. We can add our data to the Google maps in a number of forms:
- KML/KMZ - The data file format used by Google Earth. You can use points, polygons, as well as lines.
- Tab delimited or comma delimited text files - good for simple point data.
- A WMS (Web Mapping Server): a conventional web mapping server that delivers layer(s) in the WMS image format. I’ve used MapServer and ArcIMS for this purpose.
Google Maps Site Locator: (click to launch application)
This application demonstrates the use of Google Maps as the base map overlaid from West Virginia State and county lines from a KML file and point locations from a tab delimited text file. It also demonstrates the addition of a user interface that allows users to select a site either by clicking on the marker symbol or the list links in the right column. Once a site is selected the location address is shown in a popup windows and one can then click a link to get driving directions.