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Which Is More Accurate....for Geocaching On A Garm


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Hi

 

Which is More accurate....for Geocaching on a Garmin Map 60c, using ORD SRVY GB for Map Datum or the WGS 84 setting.

 

Also same goes for using the British Grid or the h ddd mm mmm setting......

 

Which one would get one closer to the goal!

 

In England only please......... :o

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I leave my Garmin set to British Grid / OSGB just about all of the time.

It is just as accurate for geocaching, if you aren't entering waypoints on the unit.

 

If you read the grid reference from the GC.com cache description, then input it into your GPSr there may be a small inaccuracy due to the difference in the conversions.

 

If you load the waypoints from your PC it doesn't matter what format / datum the Garmin is set to, as waypoints are always downloaded in WGS84.

 

As I usually do this, I have my Geko set to British Grid / OSGB - its much more useful for referring to maps. I only have to set it to degrees / WGS84 if I'm entering coordinates while I'm out, eg. for a multicache.

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If you load the waypoints from your PC it doesn't matter what format / datum the Garmin is set to, as waypoints are always downloaded in WGS84.

How do i load waypoints from my comp, I have a Legend GPS.

 

I dont know how to get the detail from the Geo site into my GPS?

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I leave my Garmin set to British Grid / OSGB just about all of the time.

Don't even THINK of submitting a cache if you have your GPS set that way :o

 

It is a recurring problem for Eckington and I when reviewing caches set by newcomers that they use the wrong datum. It is often apparent when plotting the waypoints on Memory Map but sometimes they slip through, causing all sorts of problems for cachers who go looking for the cache.

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My GPS is also set on British Grid all the time.

I've only hidden one cache - I swapped to WGS84/dms to get the coordinate.

 

If you have it set to british grid you will be able to cross reference easily with paper maps. - try doing that with WGS84

 

I download pocket queries and upload them straight into the GPS and don't need to worry about what format / datum they are.

 

It seems to make sense to use the British Grid system in Britain.... It just means you have to remember to convert to WGS84 when hiding caches.

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I'm sure I've typed this in before...

This question seems to lead down two conflicting lines, both valid. The geohikers amongst us use paper maps and therefore use OSGB etc. - on the other hand, other users who do not use paper maps generally stick with WGS84 etc. Lactodorum and co. have to deal with problems!

To me, this says, if you've no need for OS references, then don't use them! If you have a need, make sure you know what you're doing!

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I tried this tonight and came home to find this timely topic!

 

After finding a cache at Ainsdale I was taking some photos for the geograph site and used my etrex to read the degree.min coords at the spot where I took the pics. When i got home I changed the units on the etrex to British Grid without changing the datum from WGS84 to British Grid also - this put the feature I had photographed in the wrong square by about 200 - 300 meters. Switching to the OSGB datum miraculously made the features tie in with the map!

 

So if you are using your gps for geographing, please be careful to get the right grid square - better to set the GPS up for british grid units and OSGB datum before setting out!

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TIP, make sure you know how to switch between WGS94 and OSGB in the field

 

if you should have an accident there are few emergency services who know how to use WGS84 cco-ordinates, but if you give them OSGB, then you should be OK

Always use WGS 84. If you get lost and need to contact the emergency services, ie Search and Rescue teams, WGS 84 is fine because that is the system used to programme the GPS and INS (Inertial Navigation System) used on ALL the rescue helicopters in the UK. Most mountain rescue teams use both co-ords.

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