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Garmin Colorado basemap roads are way off, how do I do the automotive portion of geocaches?


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After dropping over $500 on my new colorado I expected all of my geocaching problem spots to be over ... I was wrong. Since mapopolis is off the radar I really don't have much choice in the driving portion of my geocaches. I am using iguidance for my pockepc. I was hoping to use the automotive profile on my colorado to navigate me on the road portions of my cache hunting. But the road maps are way way off. The road in front of my house is over 150 feet off. When I try to navigate to a cache using the automotive profile it says there are no nearby roads to navigate on and only gives me an as the crow flies route. I even have the 'snap to road' feature selected.

 

I have read that the City Navigator NT 2008 maps are a lot more accurate. Are we required to drop another $100 on an already overpriced item in order to do what a pocket pc program was doing 5 years ago?

Edited by themeecer
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Yes, if you want to autoroute you need to purchase autorouting maps such as CityNav. The Topo 2008 US maps are not autorouting and yes the roads are not very accurate.

 

GO$Rs

I know I am preaching to the choir but that sucks on so many levels. Even if the basemaps are off they should at least auroute us to our caches. Just one more thing to go on the bug list. I'm not all doom and gloom though .. I have faith they will patch it eventually.

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You do not need any map at all to do Geocahcing.

Basemap is what the name says, a Basic map, just to show you where you are located in the world.

Yes, but in the area I am in I need to know which road to take to get to a cache. I take the wrong one and I may be on the wrong side of the lake and have to backtrack 30 minutes on the road. Five years ago I was using mapopolis to take me straight to the cache by first guiding me on the roads I needed to get there.

 

This is the first time I had heard that a basic map = a very non accurate map. I would assume a basic map would have the main roads placed accuratly and the side roads missing.

Edited by themeecer
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If you want auto routing then you need auto routing maps. I am sorry but you bought topo maps that are very accurate. Its the road overlays that suck but thats not a part of the accuracy of the maps. Its just a add on that is not supported. It may suck but its true. Its not a fix or a feature change. If you want auto routing you need to add auto routing maps.

 

It is very possible to cache with no maps so the lack of auto routing and accurate street overlays will only slow you down a little. Its not going to stop you from finding a cache. You just have to pay more attention to how to get there.

 

Hang in there, Its a good GPS and if you want to auto route you have to buy the auto routing maps.

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Since the maps are vector base, it will be less detailed the less size you have of the map.

 

IF you look at the letter S

You have 10 coordinates to layout the "S".

This will give a nice "S" that looks like an "S" and follows the curve nice.

What happens if you have only 3 coordinates?

It will look like this /

 

This is what happens with roads/costal lines and other objects in basemap.

From distance it looks great, but it's not usable to use for auto routing.

Edited by jotne
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Since the maps are vector base, it will be less detailed the less size you have of the map.

 

IF you look at the letter S

You have 10 coordinates to layout the "S".

This will give a nice "S" that looks like an "S" and follows the curve nice.

What happens if you have only 3 coordinates?

It will look like this /

 

This is what happens with roads/costal lines and other objects in basemap.

From distance it looks great, but it's not usable to use for auto routing.

I understand that, friend, but the roads I am talking about are straight roads. They are simply in the wrong place. It isn't anything new. Most mapping programs I have used took several years to update a major bypass here in my rural area of Kentucky, and don't get me started on the detail we get on google maps.

 

I'll probably still use my iguidance on the road and estimate my entry point for hiking. It would be nice if caches listed a nearby address for easy entry into my driving software. There is probably some addon out there that will do this.

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It is not exactly as explained above....

 

The way the Garmin map format is set up is sort of a grid system. Any detail level is set up by the number of bits of information that are stored. Really rough data, that is meant to only be viewed from far out, such the basemap uses a small number of bits to save data space. The basemap uses 17 bits on the most detailed level. These are only intended to be viewed on the unit at 12 km and above.

 

17 bits gives a 315 meter (latitude) grid, so the data can be up to 315/2 = 157 meters off. Basically there is this 315 high grid that points can be chosen for each of the street nodes. The software choses the closest point on the grid to the actual location.

 

In comparision, detailed maps use 23 bits on the detailed level, which gives a 4.8 meter grid.

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The 400t comes standard with the TOPO maps. The main feature of TOPO maps are the elevation lines. The street level maps are there, but are not intended to be used for anything other than a rough estimate. The main reason you use TOPO maps is for when you are away from the streets. If you need street level accuracy and/or turn by turn routing you will also need City Navigator maps. This is fairly clearly stated in all Garmin documentation. Personally, I was just happy that the street maps were there. In my area, they are reasonably accurate, although they are somewhat out of date.

 

--Marky

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