Entering my address into Base Camp as a auto route starting point locates my house 1/2 block north of the actual position. Addresses along my street are NOT correct. There is no way I can use this program to set a travel route and depend on its accuracy.
Entering my address into Base Camp as a auto route starting point locates my house 1/2 block north of the actual position. Addresses along my street are NOT correct. There is no way I can use this program to set a travel route and depend on its accuracy.
BaseCamp is not the problem.
The error in position based on an address is a problem with all of my maps.
I have 4 different maps that will auto route to an address. I have and use a Nuvii350, iQueM5 and Edge705.
All of them have directed me to various addresses in several states.
When I get within a block of the address the gps always starts saying or showing a message on the screen that indicates that I am arriving at the destination and I have to start looking for the actual number I want.
I think it does that because the map makers know that the physical position of individual addresses is just not that precise.
Actually the precise destination has never been a problem on my travel routes.
My problems have always been trying to get the route to take me thru areas I want to see along the way without sending me on crazy loops or backtracking.
I think you will find that planning a travel route can be fun and also a challenge to your ability to beat the damn software into submission. :)
I believe the issue you are experiencing is caused by address interpolation. The address being off some, believe it or not, is not an unusual thing with GPS navigation. Addresses being off by a few feet – sometimes even a few hundred if it is a longer block of road – is possible. But, it will get someone within spitting distance of the address, even though they might have to take a good look at the house numbers or mailbox numbers to get to the precise house.
The longer the block – the longer the line on the map runs between intersections – the more you will see this stand out. If the GPS located you on the right line segment but a couple hundred feet from your home address, you are indeed seeing the effects of interpolation.
What happens is this: The data vendors put the full potential address range on a line – like 100-199 or 400-499 – rather than the actual numbers of homes. Of course, there may not actually be 100 homes on the line but all the possible addresses are attached to that line anyway. A given number may not show exactly where the driveway is because the GPS unit interpolates (averages) the position of the specific address from the potential address range assigned to the line. For instance, if your address was 28 Main Street (Y), and Main street was 1 mile long (between intersections) and has the numbers 1 – 100 assigned to it, the unit would figure that your house is located 28% of the way down Main Street (X):
100__________50____X___Y_1
In this case, the GPS is a great tool to get someone to a point where they can start looking for your address.
However, data vendors are now starting to use “Point Addressing” - assigning addresses to specific locations. Point Addressing for a city takes up a good chunk of space in a database – each address will have to contain 4 pieces of information: the address number itself, the street it’s located on, the latitude, and the longitude. For one address, this isn’t much, but multiply this by the millions of addresses that a map may contain and you can see how much data that would have to be included in the map database. The truth is, most GPS units can’t process that much information (for now).
I believe the issue you are experiencing is caused by address interpolation.
Fascinating!!!! Do you work for Navteq?
For my home address in the boonies, CNNA will get me 100ft from my garage door, but in a few recent tests in a city, it was off by a block. Great information, I was ready to give up on it's ability to find an exact address.;)
Now I know, go to where it tells you, pull over and look for house numbers......tough luck if you're on a one way street......:(
