Exploring Local
Mike Dobson of TeleMapics on Local Search and All Things Geospatial

Address Matching

May 21st, 2007 by MDob

Last month I chaired as session at the Location Intelligence conference in San Francisco on “Balancing the Accuracy and Quality of Data” or more popularly “How to Find the Right Data for Your Application”.  The session was interesting and the speakers were very generous with their advice.

One of our speakers was Mike Swartz, Senior Vice President of Information Systems and Chief Information Officer for First American Flood Data Services. As you may know, First American is a Fortune 500 company with over $8.5 billion in revenues, most generated from  businesses that are involved in various aspects of the real estate industry.  The company’s description of itself is “America’s Largest Provider of Business Information”.  Mike’s talk was focused on a First American press release from the previous day in which the company announced its new ParcelPoint Technology.  You can find the release here.

ParcelPoint ™ delivers relatively precise coordinates based on the company’s application of patent-pending technology to identify the specific geographic coordinates occurring within the boundaries of individual parcels of property.  Although I do not know any inside information on how ParcelPoint works, it is likely  that it  involves conflating  data such as property boundaries from tax maps, address information from USPS postal databases, road and street databases and aerial imagery to accurately delineate the location of houses within parcels. First American’s experience with flood plain mapping and the issuance of flood plain insurance for properties within flood plains should serve it well in developing and maintaining the ParcelPoint product.

If you are asking yourself if there is really a need for this type of product, take a look at the image below,  taken from the search results page of a major provider of local search.  The symbol used to show the location of the business is on the wrong side of the street and offset from its correct position on the other side of the street.

The address information included in many of the map databases used for local search is structured to include only a start and end postal address (tied to geographic coordinates) on each block face included in the database.  Finding the position of an actual address (geodcoding) generally involves some sort of interpolation between the end points to find a geographic location within the spatial extent of the address range.   It is clear that this calculation can be error prone, since you have no information to locate an address other than the length of the block and the start and stop address of each side of the street.

Products like First American’s Parcel Point and a similar product from Group 1 Software   (a Pitney Bowes company) called GeoStan markedly improve address-location performance and  several companies involved in local search are now using these products (either directly or indirectly) to provide superior results for locating, displaying and routing to specific business addresses.  Of course, there are still some outstanding problems with address software and next time we will look at one that really needs “fixin”.

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Posted in Geospatial, Geotargeting, Local Search, Mapping


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