Different lat and long for same address

[Stella-MarisAgu]

I Geocoded a list of address (Mostly intersections) for bus routing and the same address was geocoded by a different company. The lat and long values that I get is different from the one from the company. I calculated the difference in excel as shown below. Some seem too big. My question is how much is too big? (Calculation in metres). Looking at the table and map it seems not too far off but when I measure the distances in a straight line it seems much as shown in the table. I used projected coordinate system. I am trying to decide which of the coordinates(Lat/long) is the more precise and accurate so the bus will not miss a student. Is it okay to get varying lat and long for same address? Please can anyone help? Any help with geocoding intersections will be appreciated. I checked the match with no house number to Yes.

Thank you

[JoeBorgione]

I used to work in a 9-1-1 call center that dispatched about 2,000 calls a day.  The data I used to match against was constantly being updated for accuracy, and we had about a 99.5% accuracy rating; in 9-1-1 you need that, right?!  Those data sources were fantastic, but took a ton of work to maintain for that sort of performance.  And, that's all I did.

A couple of anecdotes: Once a dispatcher told me we should use Google maps as the basis for dispatch.  I told him that would be fine with this caveat: he use Google when dispatching to his mothers house, and my data when dispatch to my house....  Another dispatcher complained to me that "Google doesn't update their data like you do;  Why not? What is their update schedule? "

[Stella-MarisAgu]

Thanks Joe! Your reply to the dispatcher made me laugh out loud. Use Google at your own risk lol. I badly need your kind of data sources but like you say it takes a lot of work to maintain that high accuracy. I get road data from the government but that is not without accuracy issues. I am looking for other data sources to supplement. How did you go about gathering and maintaining Reference data for such a high accuracy.

[JoeBorgione]

I had a wonderful situation where the 9-1-1 center I worked for dispatched for a number of cities, and using an Enterprise GDB the city GIS people maintained thier 'piece of the pie' for street centerline data.  It worked out really really well.  The county in which we were all located has an excellent addressing department that maintains individual  structure addresses as points so between the streets and address points, it was pretty bomb proof.  All that data has been worked for a number of years; it's not like we just opened the box and there it was: Lot's of coordination between agencies with respect to naming conventions etc.