[postgis-users] Missing GEO data

[Dan Putler]

Hi Mikal,

I assume you are talking about results you are getting from the PostGIS 
TIGER Geocoder. The US Census Bureau does not provide address points, 
which is what would be needed for "rooftop" geocoding, and under Title 
13 of the US Code, they legally can't for privacy reasons. What the US 
Census Bureau does provide is street segments with address range 
information as part of their TIGER/Line product. However, this address 
range information has been obfuscated to a certain extent to be 
compliant with Title 13. What this means is that the geo-positioning 
will me a bit off for most addresses, will always be along the street 
and not on the rooftop, and will purposely have some missing addresses. 
If you truly need rooftop geolocations (which is needed for emergency 
response, but few other applications), you will need to use something 
other than the TIGER data. If you want it for a small area, say a county 
or the Borough or City of Anchorage, you can consider basing an address 
point data set from a local parcel layer along with the parcel situs 
addresses obtained from the relevant local government agencies (likely 
both the GIS group and the Assessors Office). Address point data can 
also be obtained from commercial vendors, such as NAVTEQ.

News reports indicate that the Census Bureau is willing to release the 
Master Address File to the public, but this would require Congress to 
amend Title 13 of the US Code.

Dan

On 12/20/2011 01:02 PM, Mikal Laster wrote:
> Hello,
>
> I apologize if someone has already posted this, but when trying to 
> geocode some addresses:
> ('1301 W 100th Avenue Anchorage, AK 99515', '651 E 100th Avenue, 
> Anchorage, AK 99515',
> ) . Getting Street level coding and the not the rooftop.
>
> ("(,E,100th,Ave,,,Anchorage,AK,99515,t)",0101000020AD100000083BC5AAC1BB62C095986725AD904E40,9)
> ("(,W,100th,Ave,,,Anchorage,AK,99515,t)",0101000020AD1000001EDB32E0ACBC62C04815C5ABAC904E40,9)
> ("(,E,100th,Ave,,,Anchorage,AK,99507,t)",0101000020AD10000092CA147310B962C0B6476FB88F904E40,11)
>
>
> Is there a known issue with not all of the valid address being 
> inserted or even recorded by the Census? These addresses exist. Please 
> advise.
>