Step 1.
Issue one:
specially for over 100 years old city, lot of home owner build extra 2-story-apartment-like building in their backyard for rent.
The extra building have new address, which is valid in USPS address database as deliverable address,
However these extra building's new address is not recorded in county parcel system.
County parcel address is only allow one address for one parcel.
Even same parcel have 2 building, 2 address, county only record one address.
Step 2.
Issue two:
In real world, some home owner use different address number as county's parcel address. Even their parcel address number is A, the home owner just put number B on their door, which is a valid address in USPS.
Number B maybe their historical address? Maybe some other reason that I don't know.
For police use, we need what ever address owner currently use.
Step 3.
Issue three:
Business address seems like randomly picked by owner. Some new business open in same place, the business owner decide to use a new different address number from old business to avoid duplicate.
This is understandable. The closed business is a pizza store use address A. A new dental business rent this same store, they could use same old address. If you search old address, it always says is pizza store. Because google map need a while to update that pizza store is closed. If you choose a new address number, then you sign up in yelp and google, telling them you are open a new dental store in this new address. People search new address will immediately showing a dental store.
Step 4.
USPS is a tool to validate address, but USPS does not have a map, you know address A is valid deliverable, but you don't know where address A is.
USPS address validation can be used as a assistant tool with google map, apple map, esri map.
Step 5.
county have address working group https://dqm.gis.lacounty.gov/
Step 6.
CAMS validations is county's method to validate address https://dqm.gis.lacounty.gov/
Step 7.
county have build a work flow of address validation https://dqm.gis.lacounty.gov/
Step 8.
you can upload your address to get result as below. https://dqm.gis.lacounty.gov/
Step 9.
county address also use NENA standard which is national standard for NG911 https://dqm.gis.lacounty.gov/
Step 10.
this is part of county address validation work flow https://dqm.gis.lacounty.gov/
Step 11.
County just build this new work flow https://dqm.gis.lacounty.gov/
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Step 18.
if you want to consulting with them, you can make appointment here
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