Map Help

[+ijdpsg]

I'm pretty new to geocaching, and I really love it.

 

We have a Garmin Etrex Legend CX and it is great for all our needs. There is just one problem, but I don't know if it's just me being thick!

 

I go to a geocache on Google Earth, and it shows me exactly where it is. I then put these co-ordinates into my Map Source program and it also put it on there. Most of them are right, but I noticed this weekend the caches around the River Mersey (Sale Water Park) were showing on Map Source on the wrong side of the river. You follow the GPS and it takes you to where it is exactly, on the right side of the river. It's just Map Source and the map on my GPS that seem incorrect, the co-ordinates seem perfect.

 

Am I missing something? I must be doing something wrong. It's not that bad, at least it takes you to the correct place on the road, just got to make sure which side of the river!

 

Does all this make sense?

 

Thanks in advance,

 

Paul

[Nediam]

The locations shown on Google Earth are NOT exactly correct. There is an in built degree of error to prevent you from being able to get the exact co-ordinates without using the Geocaching.com database.

[+ijdpsg]

Well, Google Earth takes me to the right side of the river then.

 

I was thinking that maybe the Map Source line for the river could be wrong?

[Nediam]

Well, Google Earth takes me to the right side of the river then.

 

I was thinking that maybe the Map Source line for the river could be wrong?

I've never used MapSource or any built in mapping on a GPS so I've no idea what the quality of them is like Perhaps someone else who uses them might have a better understanding of what the problem might be. Anyway, good luck with your caching

[+Team Sieni]

Most of them are right, but I noticed this weekend the caches around the River Mersey (Sale Water Park) were showing on Map Source on the wrong side of the river. You follow the GPS and it takes you to where it is exactly, on the right side of the river. It's just Map Source and the map on my GPS that seem incorrect, the co-ordinates seem perfect.

 

NB I don't know anything about your model of GPS (Garmin Etrex) only my own (Garmin GPS Map 76S) so this could be way off beam.

 

Here goes anyway

 

It could be that you don't have the detailed map for your area downloaded to your GPSr, you just have the "base map".

 

The base map in a Garmin GPSr is a fairly rough & ready map of everywhere. Because it covers the whole (???) world the detail is limited and liberties have been taken, such as straightening out kinks in roads and rivers and so on. My house is (on my Garmin GPSr) on the "wrong side" of the railway.

 

You download more detailed maps from your Mapsource CD, for example I have Europe Roads and Recreation. More modern snazzier Garmin GPSs can download topographical maps.

 

So when I download my local map to my GPSr, magically, the detail is added in to the railway and my house is back on the right size of the tracks.

 

PS I always figure where the cache is on a paper map and only use the GPS for the last few 100 metres. But I'm old fashioned like that.

[+ijdpsg]

Thanks for your reply.

 

I was thinking that they had just used straighter lines than what the river actually is, so some things are on the wrong side.

 

Don't know why I'm bothered really though, as my gps takes me to the right co-ordinates anyway!

 

Thanks,

 

Paul

[+Midnight Ramblers]

I have the same GPSr and it has also been known to get water (e.g. a canal on Sunday) incorrect. That is with the OS topographical map loaded. It can be very distracting - my brain is keener to believe the little picture on the screen rather than the highly accurate mathematics involved in telling me that I am only 6 feet away from the cache .

[+purple_pineapple]

And of course the natural inclination to follow the arrow could result in a somewhat damp GPSr (and cacher) if you start on the wrong side of the river!!!

[+Pharisee]

If you're running MapSource, then I assume that you've also got one of the 'road' based mapping products. City Select, City Navigator or perhaps one of the earlier products. These are notoriously inaccurate when it comes to 'non-road' features like rivers, lakes, canals and railway lines. They are very good for roads, though. Their Topographical maps are great. The rivers etc. are all shown much more accurately.