Open Source Solutions

Geo-targeting is commonly used to localize content such as adverts and for statistical purposes. This process is also known as localization.
The problem with Internet based geo-targeting is that it tends to be a rather inprecise affair and can not be relied upon to be 100% accurate. In order to obtain a web site's visitors geographical location. We first need to obtain a visitors IP address and then compare this address to a database of known (county specific) IP ranges. However, the accuracy and performace of many of the freely available SQL database or CSV based solutions tends to be extremely poor.
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Prefuse supports a rich set of features for data modeling, visualization, and interaction. It provides optimized data structures for tables, graphs, and trees, a host of layout and visual encoding techniques, and support for animation, dynamic queries, integrated search, and database connectivity. Prefuse is written in Java, using the Java 2D graphics library, and is easily integrated into Java Swing applications or web applets. Prefuse is licensed under the terms of a BSD license, and can be freely used for both commercial and non-commercial purposes.

Many GIS resources can also be found on the web. You can navigate our collection of links by selecting a topical area or category from the list below.

This interesting paper compares the performance of the Ontok Geocoder to 3 popular geocoders on 53 addresses in Houston, TX: geocoder.us, Teleatlas (used by Google Maps) and Yahoo.
This is a small sample, but indicates the general quality of whether a geocoder can: (a) return any coordinate at all, given an address (b) return an accurate result, measured in number of feet off from the "ground truth" data provided by FEMA.

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Very interesting benchmark of mapping services by Techcrunch.
"Overall, Yahoo Maps was by far the best application tested. Its fast Flash interface, multipoint directions, live traffic information, and easy send-to-mobile feature make it the hands down winner. It also features the most robust API options."
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