+Chalky723 Posted January 8, 2005 Share Posted January 8, 2005 Hi All, A quick poser - I'm usting the normal lat-long coordinates on my GPS for adding waypoints. But if I want to use it in conjunction with my map, when I switch the Datum etc to comply with the map and it then shows the waypoint as a grid reference is it accurate? It'd be nice to be able to use the map to get close which is a bit awkward using lat/long... Cheers, Chalky Quote Link to comment
+NightPilot Posted January 8, 2005 Share Posted January 8, 2005 Yes, it's accurate. At least as accurate as the GPS. There are of course rounding errors, but those will be on the order of a couple of feet at most, and the GPS isn't nearly that accurate. Quote Link to comment
+Alan2 Posted January 8, 2005 Share Posted January 8, 2005 What map are you using? Quote Link to comment
+Chalky723 Posted January 8, 2005 Author Share Posted January 8, 2005 Good old paper Ordinance Survey - so a few feet isn't going to make any difference. I just thought it'd be nice to be able to cycle around using the map & then the GPS for the vital last 500m. Chalky Quote Link to comment
+pathfind2003 Posted January 9, 2005 Share Posted January 9, 2005 The difference between NAD27 and WGS84/NAD83 can be off as much as 200 meters. The difference isn't always that large, but is usually off. Quote Link to comment
+Alan2 Posted January 9, 2005 Share Posted January 9, 2005 Good old paper Ordinance Survey - so a few feet isn't going to make any difference. I just thought it'd be nice to be able to cycle around using the map & then the GPS for the vital last 500m. Chalky What Datum does the map use? Quote Link to comment
+NightPilot Posted January 9, 2005 Share Posted January 9, 2005 As he said, Ordnance Survey. It's a British thing. Quote Link to comment
+Alan2 Posted January 9, 2005 Share Posted January 9, 2005 British?!? Well I can't help! I'm still trying to figure out the Metric system. Quote Link to comment
+dunos Posted January 9, 2005 Share Posted January 9, 2005 British?!? Well I can't help! I'm still trying to figure out the Metric system. Thats ok, we are far from being completely metricated by Europe. We still order beer and milk by the pint, measure distance in miles, height in feet and inches and weight in stone. Dan Quote Link to comment
+Alan2 Posted January 9, 2005 Share Posted January 9, 2005 Really? I thought you used kilometers for distance and height. I guess you're still trying to figure out the Metric system too Quote Link to comment
+EraSeek Posted January 9, 2005 Share Posted January 9, 2005 (edited) If you input the coords in Lat/ long, and WGS84 for say a cache, then switch to any other map datum, or any other format than Lat/Long, the cache coords will convert and be correct. However if you input a coordinate from another a map using another datum while in WGS84 datum and then switch to the original datum it will be off. Inother words. You have to use the datum that the map uses to match the map. Your GPS will convert any format or datum accurately as long as it was input properly for the system your GPS was in at the time. Edited January 9, 2005 by EraSeek Quote Link to comment
+Chalky723 Posted January 9, 2005 Author Share Posted January 9, 2005 Thats ok, we are far from being completely metricated by Europe. We still order beer and milk by the pint, measure distance in miles, height in feet and inches and weight in stone. The maps are in Kilometres though!! I prefer metric myself - I know how heavy a Kilo is & how far a Km is, I always convert miles to metres, as for leagues, rods, chains, yards & furlongs...... Thanks for the replies chaps. Chalky Quote Link to comment
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