Oregon 400t: TOPO maps / tracking

[rockstar_not]

Just bought a Garmin 400t. Searching the forums here but perhaps I'm not asking the question properly.

 

When looking at the built-in TOPO map and driving, vehicle position is always about 200-300 ft off of actual road in the map. Should it have better accuracy?

 

I'm wondering which selection I should set for North - if that's the issue. I'm in Colorado Springs at about 6800' elevation.

 

-Scott

[+mpilchfamily]

That does seem a bit too far off. Have you checked for any firmware updates? Now there is always some degree of inaccuracy in the maps. There will be a setting for snapping the icon on top of the roads somewhere in the settings. Some times that maps can be more inaccurate then others depending on the location. But i don't know is 200 to 300 feet is within the typical margin.

 

Changing between magnetic or true north shouldn't effect your position on the map.

[+myotis]

The built in maps are 100K topo maps so it is very common for roads to be that far off.

 

You can get much better and accurate maps at gpsfiledepot.com You can get one of the CO topo maps and My Trails has trail coverage for CO) However, you need City navigator if you want driving directions.

[+New Jersey TJ]

Even the routing street maps may be off to some point. Chances are that the GPS is accurate, but the maps may be off. If you wind up using routing street maps, the 400T has a "lock on road" feature that can be turned on. It will make the GPS display your postition on the closest road, so you won't be bothered by slight inaccuracies of the map. That feature won't work, though, with the built-in topo maps.

[+EraSeek]

Whenever I hear 200'- 300' I think Map datum. Just check to make sure your unit's map datum is set to WGS 84.

[+myotis]

Whenever I hear 200'- 300' I think Map datum. Just check to make sure your unit's map datum is set to WGS 84.

 

Map Datum has absolutely nothing to do with this. You can change your datum to anything you want and it have any impact on your issue. Datum will impact what lat and long displaces for a certina point, but it has absolutely nothing to do with where your GPS displays your current position on the map.

[yogazoo]

I don't think people realize just how crappy the Tiger 2000 data is in some places (used for the roads in the Topo U.S. 2008 series). I'm talking BAAAD.

[rockstar_not]

I don't think people realize just how crappy the Tiger 2000 data is in some places (used for the roads in the Topo U.S. 2008 series). I'm talking BAAAD.

 

Found my first cache with the unit today and it put me directly on top of the cache without issue. The map was off, but GZ was spot on.

 

I'm wondering if anyone can recommend which map to obtain for driving use.

 

BTW, datum is WSG84 and latest firmware installed.

Edited June 3, 2011 by rockstar_not

[+CacheFreakTim]

I don't think people realize just how crappy the Tiger 2000 data is in some places (used for the roads in the Topo U.S. 2008 series). I'm talking BAAAD.

 

Found my first cache with the unit today and it put me directly on top of the cache without issue. The map was off, but GZ was spot on.

 

I'm wondering if anyone can recommend which map to obtain for driving use.

 

BTW, datum is WSG84 and latest firmware installed.

 

That is strange, so the coords. are correct but the map is what is off? I wonder if you load another map, like the free topo maps from gpsfiledepot and see if it does the same thing. Sounds like a software issue though which is a good thing.

[+Walts Hunting]

Even the routing street maps may be off to some point. Chances are that the GPS is accurate, but the maps may be off. If you wind up using routing street maps, the 400T has a "lock on road" feature that can be turned on. It will make the GPS display your postition on the closest road, so you won't be bothered by slight inaccuracies of the map. That feature won't work, though, with the built-in topo maps.

 

Actually it doesn't work that way. The 400t comes with the 100K topo which are not routable. It doesn't know where roads are so lock on road has no effect except for the major highway basemap roads.

 

For that feature to work you need city navigator or 24K topo.

Edited June 4, 2011 by Walts Hunting

[+New Jersey TJ]

Even the routing street maps may be off to some point. Chances are that the GPS is accurate, but the maps may be off. If you wind up using routing street maps, the 400T has a "lock on road" feature that can be turned on. It will make the GPS display your postition on the closest road, so you won't be bothered by slight inaccuracies of the map. That feature won't work, though, with the built-in topo maps.

 

Actually it doesn't work that way. The 400t comes with the 100K topo which are not routable. It doesn't know where roads are so lock on road has no effect except for the major highway basemap roads.

 

For that feature to work you need city navigator or 24K topo.

 

You're right. That's why I said "If you wind up using routing street maps . . ."

Edited June 4, 2011 by New Jersey TJ

[rockstar_not]

Even the routing street maps may be off to some point. Chances are that the GPS is accurate, but the maps may be off. If you wind up using routing street maps, the 400T has a "lock on road" feature that can be turned on. It will make the GPS display your postition on the closest road, so you won't be bothered by slight inaccuracies of the map. That feature won't work, though, with the built-in topo maps.

 

Actually it doesn't work that way. The 400t comes with the 100K topo which are not routable. It doesn't know where roads are so lock on road has no effect except for the major highway basemap roads.

 

For that feature to work you need city navigator or 24K topo.

 

You're right. That's why I said "If you wind up using routing street maps . . ."

 

So - I'm sure there's a thread here somewhere on Groundspeak which talks about how to do city navigator or the 24k topo - are these legally available for free or a small charge? I bought a 4GB micro sdhc for the unit which is installed and ready for maps. Anyone care to point me in the right place?

[MtnHermit]

So - I'm sure there's a thread here somewhere on Groundspeak which talks about how to do city navigator or the 24k topo - are these legally available for free or a small charge? I bought a 4GB micro sdhc for the unit which is installed and ready for maps. Anyone care to point me in the right place?

I use these maps, not free but you get what you pay for. Download the free sample maps to test in your 400T tonight.

[rockstar_not]

So - I'm sure there's a thread here somewhere on Groundspeak which talks about how to do city navigator or the 24k topo - are these legally available for free or a small charge? I bought a 4GB micro sdhc for the unit which is installed and ready for maps. Anyone care to point me in the right place?

I use these maps, not free but you get what you pay for. Download the free sample maps to test in your 400T tonight.

 

I actually was able to get a colorado-specific topo loaded last night from gpsfiledepot - same issue; tracks roads off quite a bit. Still puts me right on top of caches however. I guess it's time for city navigator.

[+ecanderson]

I actually was able to get a colorado-specific topo loaded last night from gpsfiledepot - same issue; tracks roads off quite a bit. Still puts me right on top of caches however. I guess it's time for city navigator.

To keep apples and apples - be sure you are running in OFF-ROAD mode when you use City Navigator so as to shut off the 'road-snap' feature. That feature is common to road GPS modes and fudges the displayed location in attempt to show you on a road when the coordinates say you're not. You may well find that the roads in your area just aren't geolocated for squat no matter whose map you are running.

[rockstar_not]

I actually was able to get a colorado-specific topo loaded last night from gpsfiledepot - same issue; tracks roads off quite a bit. Still puts me right on top of caches however. I guess it's time for city navigator.

To keep apples and apples - be sure you are running in OFF-ROAD mode when you use City Navigator so as to shut off the 'road-snap' feature. That feature is common to road GPS modes and fudges the displayed location in attempt to show you on a road when the coordinates say you're not. You may well find that the roads in your area just aren't geolocated for squat no matter whose map you are running.

 

I tried turning the navigation to 'off-road' and this did seem to help significantly. With that said, I don't have City Navigator, so I don't know whether I'll be able to use turn-by-turn directions or not, if navigation is off-road.

[rockstar_not]

I actually was able to get a colorado-specific topo loaded last night from gpsfiledepot - same issue; tracks roads off quite a bit. Still puts me right on top of caches however. I guess it's time for city navigator.

To keep apples and apples - be sure you are running in OFF-ROAD mode when you use City Navigator so as to shut off the 'road-snap' feature. That feature is common to road GPS modes and fudges the displayed location in attempt to show you on a road when the coordinates say you're not. You may well find that the roads in your area just aren't geolocated for squat no matter whose map you are running.

 

I tried turning the navigation to 'off-road' and this did seem to help significantly. With that said, I don't have City Navigator, so I don't know whether I'll be able to use turn-by-turn directions or not, if navigation is off-road.

[+myotis]

Turning navigation to off road should NOT help with your problem.

 

Anyway I would go ahead and get City Navigator. When you got it on gpsfiledepot, get CO Transparent Topo, My Trails, My POIs, and Western landOwnership. (I make all of them) They are designed to be transparent overlays for City Navigator