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Fletch Regular Visitor
Joined: 24/06/2003 16:30:46 Posts: 85 Location: Staffordshire, UK
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Posted: Tue Feb 10, 2004 8:04 pm Post subject: AtoZ maps |
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Could anyone tell me why, with all the mapping Irregularities that tomtom and copilot have, with out of date maps etc. That they don’t approach someone like A to Z to provide there mapping or why is it that A to Z who have there detailed maps available for use on pocket pc at, may i add, a more favourable cost, that, they themselves don’t provide the additional GPS software to allow there maps to be used with a GPS system?
Has this avenue been explored? Or am I way behind with my thoughts?
Kind regards
Fletch
By the way the site is excellent and a valuable source of information I personally have spent hours trawling through page after page of comments by other users on the forums and the detailed reviews are brilliant
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lbendlin Pocket GPS Staff
Joined: 02/11/2002 22:41:59 Posts: 11878 Location: Massachusetts, USA
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Posted: Tue Feb 10, 2004 8:48 pm Post subject: |
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I hav never heard of A to Z (and the same may be true for the folks at NavTech or TeleAtlas). Anyhow, it is not that easy. You may get the initial map material in a decently digitized format, but then you will have to fill in all the blanks. Each road segment (every little piece of road that is different from the next piece) has up to 150 properties like width, direction of travel, road class, speed limit, bridge height, weight limitation etc etc that need to be surveyed and maintained by the map providers. As you can imagine those databases are HUGE...
Once this is done the navigation systems vendors purchase a limited subset of these 150 parameters (a question of money and target map size) to compute the maps that you and I are buying eventually.
So A to Z may have nice scans, but they may miss out all the other parameters which makes their data useless for computation. Maybe - As I said I have never heard of them, so I am just guessing. _________________ Lutz
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Fletch Regular Visitor
Joined: 24/06/2003 16:30:46 Posts: 85 Location: Staffordshire, UK
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Posted: Tue Feb 10, 2004 9:18 pm Post subject: |
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Thanks for your reply, AtoZ is one of the oldest and largest independent map publishing companies in the uk and provide road atlases for the entire UK and some of Europe. check out there site at www.a-zmaps.co.uk and you will see that they have available digital maps for the pocket PC which brings me back to my original Question.
By the way i don't work for them and im not trying to give you or anyone a history leason
Kind regards
Fletch |
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lbendlin Pocket GPS Staff
Joined: 02/11/2002 22:41:59 Posts: 11878 Location: Massachusetts, USA
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Posted: Tue Feb 10, 2004 9:33 pm Post subject: |
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Ahh, that's where it comes from... Loosely spoken , A-Z equals Memory Map equals MapTech (not to confuse with NavTech).
So all they've got are nice looking raster maps that are not suited for road navigation (but are excellent for offroad or orientational stuff). Sorry, those raster maps are not suitable for what you want to achieve. There is one vendor (Delorme) who already tries to combine Raster and Vector maps, but the results are, uhm, not yet impressive. It will take another year or two before we will see hybrid products that are really useful. _________________ Lutz
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Fletch Regular Visitor
Joined: 24/06/2003 16:30:46 Posts: 85 Location: Staffordshire, UK
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Posted: Tue Feb 10, 2004 9:44 pm Post subject: |
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slow down tiger, ive completly lost you what the F@~# is a raster map and a vector Map???? |
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lbendlin Pocket GPS Staff
Joined: 02/11/2002 22:41:59 Posts: 11878 Location: Massachusetts, USA
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Posted: Tue Feb 10, 2004 10:03 pm Post subject: |
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sorry, I got carried away
Raster Maps have a certain "resolution". Each dot (pixel) represents a square of , let's say, 100x100 feet in the real world, and can only have one color. No matter how far you zoom in to a raster map, this resolution does not change. It is like taking a paper map and scanning it in. (That's what Memory Map did, actually) . Raster maps don't know about streets or walls or rivers - all they know are black and yellow and blue pixels.
Vector maps work with vectors (quite a surprise, ah?) Simplified, a vector is a coordinate, a destination, and a length. Something like "This piece of road starts here and then goes south west for .5 miles" . Using this vector information, maps can be drawn in any resolution you want, and still be extremely precise, without any pixelation.
The road system is described in the databases as a gigantic heap of vectors and polygons (multiple vectors in a closed circuit), and this allows to define routes that are actually happening on the streets and not 50 yards to the left of them - Quite different from the " as the crow flies" (that's the best a raster map can give you).
Hope that helps, _________________ Lutz
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Fletch Regular Visitor
Joined: 24/06/2003 16:30:46 Posts: 85 Location: Staffordshire, UK
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Posted: Tue Feb 10, 2004 10:09 pm Post subject: |
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wow!!!
Im sorry i asked now!!
But thanks for clearing that one up
so the answer to my original question is no and don't ever ask silly questions again, right
Thanks again |
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Darren Frequent Visitor
Joined: 11/07/2002 14:36:40 Posts: 23848 Location: Hampshire, UK
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Posted: Tue Feb 10, 2004 10:13 pm Post subject: |
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You are not comparing like with like here. AtoZ's maps are just digital copies of the paper equivalent. They contain none of the data necessary to permit route calculation and as such are only of use as a reference. Even with a GPS facility they would only be able to show your position.
Bear in mind that the AtoZ maps are effectively digital images, they know not where a road boundary begins or ends nor in fact anything about the data they display! Also because they are images they require huge file sizes. An AtoZ street level map of the entire UK would require gigabytes of storage space!
A vector map contains data in such a way that it maintains its detail at any zoom level. It contains the data in such a way that it can be re-drawn at any scale on the fly whereas a raster map (which AtoZs are) is designed for viewing at a single specific zoom level only. Zooming in or out drastically reduces detail, to compensate for this the image would need to be provided at many different scales multiplying the file sizes again. Memory-Map uses raster maps. Used for hiking or trekking this is not an issue but for road navigation it is a non-starter. _________________ Darren Griffin |
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Fletch Regular Visitor
Joined: 24/06/2003 16:30:46 Posts: 85 Location: Staffordshire, UK
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Posted: Tue Feb 10, 2004 10:28 pm Post subject: |
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Cheers darren that clears that up
thanks |
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