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August 2006 Archives

August 19, 2006

2000 vs. 2005 ZCTA's

There is quite a bit of difference between the 2000 ZCTA's that can be downloaded from the census bureau and the ones that can be extracted from the 2005SE Tiger/Line database. There are changes to just about every zip code plus the 2005SE extract has a lot more detail.

To view these differences, check out this tool:

August 20, 2006

Reverse Geocoder expanded coverage

The reverse geocoder has been expanded to include the following states: South Carolina, North Carolina, Virginia, West Virginia, Delaware, Maryland, New Jersey, New York, Massachusetts, Connecticut, New Hampshire, Vermont, Maine, Washington, D.C. More are to be added in the coming weeks. The entire US should be available by the end of September.

Updated ZCTA Zip Codes

The ZCTA Zip Code polygons that are used in the zip code map have been updated to those found in the Tiger/Line 2005SE dataset. These updated zip codes reflect a much more accurate picture of the actual zip codes. The old zip code boundary map (zipv0.htm) will still use the original 2000 census data, so use that page if you need the original data.

You can compare the 2000 ZCTA's to the 2005SE ZCTA's using this page:

August 21, 2006

Missing data in 2005SE ZCTA Zip codes

It has been brought to my attention that there are some blank areas of the new maps, notably in Jefferson County, KY. I researched the problem and both to my consternation and delight, it is due to errors in the Tiger/Line data and not the program I wrote to resolve out the new ZCTA's.

The 2005SE Tiger/Line data for state 21, county 111 (Jefferson County, KY) has ZCTA's only for the bordering counties but none at all for the ZCTA's internal to the county. I guess somewhere along the line this information was lost. I can only hope that it will be added back in at some point.

In the event that other missing data is suspected, it can be confirmed by using the 2000 ZCTA vs. 2005SE ZCTA tool ( I wrote. Please report any problems of this nature to me using the contact form (click here).

August 22, 2006

Update: Missing data in 2005SE ZCTA's

I received a note back from the Census Bureau, Geographic Products Management Branch, regarding the data error I discovered. Turns out the Tiger/Line product is not at fault as I suspected. The fault, dear Brutus lies in ourselves, not the stars... Somehow, during the automated process of loading the Tiger/Line data, the "I" records for Jefferson County, KY didn't get loaded. I will have to write a program to verify the entire data set now.

Actually, this is both good news and bad. Good news in that the Tiger/Line data has been vindicated. Bad news in that there was a glitch in the automated process to load the data. Regardless, writing a verification program will give me greater confidence in the data.

About August 2006

This page contains all entries posted to / USNaviguide LLC in August 2006. They are listed from oldest to newest.

September 2006 is the next archive.

Many more can be found on the main index page or by looking through the archives.

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