Presenting Spatial Data Using Web Mapping Services

Abstract

In the last chapter I showed you how to build a web page that consumes a GeoRSS feed from SQL Server and displays the data contained in that feed on a Microsoft Virtual Earth or Google Maps control. While this provides a convenient way to present spatial information, it does not allow for much flexibility in how that information should be displayed-both Google Maps and Virtual Earth present GeoRSS feeds by applying a standard template that is difficult to customize. Displaying GeoRSS information has other limitations-each item in the feed can be represented by only a single geometry, and the information that can be displayed on the map is limited to those columns of data specified by the Atom or RSS format on which the GeoRSS feed is based. For instance, you cannot easily display different colored markers based on the price of each property in a GeoRSS feed, since the RSS and Atom syndication formats do not contain any elements that record a monetary value relating to each item.