House number position accuracy

[TonyGr]

When I got my new Basic I set the Home location to my address using the search option. I have always been aware that the PND thinks still have about 50 yds to go when I pull onto the drive but as I know my own house I have ignored it.

Today I dug out the pdf of the full instruction book with the intention of setting the Home location accurately. Following the instructions with the device out in the open and receiving satellite location data I tapped and held on the location indicator (blue triangle) and the location address came up as 3 houses away from mine. No wonder it thought I still had 50 yds to go.

Are the maps generally inaccurate as to the position of individual house numbers? No so good when looking for a new address.

I suppose the advantage, now it is reset, nobody will know my true address.

 

[canderson]

Depending upon the area, house numbers may still not be precisely known, but instead, spread over the space across which numbers are assigned. So if the block is 1100-1200, it is possible that an address may be approximated in position along that stretch of street based upon it's position within the numbers. For example, 1150 may be placed mid-block.

You can, of course, identify the point on the map rather than by address to reassign 'home'.

That said, there have been a few arguments presented as to why you might not want your precise home address on your GPS. I take it from your car in a shopping parking lot, see where you live, know you are probably not home...

 

[Arno]

When I lived in a house I designated the nearest intersection coordinates as Home.
Since moving to a Condominium I am using the coordinates for the middle of the drive way and curb, kerb for you. ;->)

 

[TonyGr]

You can, of course, identify the point on the map rather than by address to reassign 'home'.

That is what I did which it then identified as a house number three doors away which prompted this thread.

 

[Arno]

That is what I did which it then identified as a house number three doors away which prompted this thread.

Nothing new. I had that already with my NAV2 930 in 2008.

 

[canderson]

That is what I did which it then identified as a house number three doors away which prompted this thread.

Did it MOVE your preferred location, or simply assign an address to it that was offset a bit? As explained in post #2, the latter is entirely explainable. Not all areas have individual address assignments for every building yet, though this is one reason that the map files keep getting larger and larger.

 

[TonyGr]

It assigned a house number 3 doors away. When I change the location to further up the road the assigned house number changes until I get my number about 50 yards beyond my house.
Clearly the assignment is out but by the end of the road the last house is correctly placed.

Thinking about possible reasons I wonder if the cause could be due to the fact that the first 20 houses have approx 25ft frontages, ours is 90ft and the remainder are 40ft. If TT have spread the house numbers evenly over the distance then that could explain it. Interestingly, however, if you zoom in on Google Maps then the houses show as individual (or pairs for the semis) with the numbers correctly allocated. Again using Google to determine the coordinates of my drive and entering them into the TomTom comes up with the same incorrect house number which tends to confirm the above theory.

It does raise the question that if Google have access to accurate house placements then why has TT not used the same data?

 

[Niall]

TonyGr​

It does raise the question that if Google have access to accurate house placements then why has TT not used the same data?

The main reason is the storage of the details! When you zoom in Google you drag the info from their terabytes of on line storage, whereas on your device, when zooming in, all that info has to be held within the gigabytes (UK 1.6GB)of it's limited storage

Edit: On searching

Google's database is estimated to be in the range of 100-500 petabytes (PB), or even larger. A petabyte is equivalent to 1,000 terabytes (TB) or one million gigabytes (GB), so this is an enormous amount of data.

 

[TonyGr]

Thanks Niall. I should have thought it through.