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map76s base map inacurate?


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quote:
My base map seems to be off sometimes. I have to zoom way out to get my travel line to match up with the base map road.

 

?? What is "zoon way out" ? What zoom scale are you talking about?

 

?? how far off of the road does your position appear to be? (you can use 'measure distance' to get an estimate)

 

I have a 76S and have used the basemap, TOPO, and City Select with it and the accuracy of all maps has been VERY good.

 

"Never have a philosophy which supports a lack of courage..."

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Yup. The 76S' basemap is a mess.

Mapsource Citystuff is muuuuch closer to reality.

 

I had a cache that the basemap said was southwest of a railroad crossing a road; it was northeast by about 200 feet!

 

But remember: the map is not the territory. If the map was as accurate as the territory, it would be the territory.

 

I am Arrowroot, son of Arrowshirt. I have many names, you know

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The accuracy of the maps tend to vary quite a bit depending on where you are. For much of the area I navigate in, the basemap tends to be off by several hundred feet, as do the R&R maps, or earlier metroguide maps. The TOPO map has the roads a little more accurate, but the data is about 20 years old, and this area is growing fast. The City NAV, City select, and the latest version of Metroguid which is based on the same data base tend to be quite a bit more accurate.

 

One thing GPS has indeed shown us is just how bad some of the older maps were.

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The base map on my Legend covers pretty much the whole of Europe. To cover an area that size in the same detail as the MetroGuide maps would need a huge amount of memory. What they appear to have done (and this is just a guess on my part) is to plot fairly accurately the major road junctions and then join these points up with straight lines to represent the roads. When using the base map, my track wanders quite a long way off the indicated road but they appear to come together again at major interchanges.

 

John

 

Age and treachery will always triumph over youth and ability.

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