TxFilmMkr Posted September 4, 2003 Share Posted September 4, 2003 New user here. This may be an easy question but I've searched the forums for solutions and tried all I've found but I'm still having the same problem. I've got a Magellan Sportrak and downloaded local maps onto the unit for my area using MapSend Topo. When I'm driving or walking along, my position on the map doesn't match up to where I am physically. For instance, if I'm driving down a street and get to an intersection, according to the map, my unit says I'm abuot 150 feet from where I actually am. Even when I download the route from my unit to my computer, it mirrors what was on the unit, with the route being nowhere near where I actually went. Here's what I've tried. Leaving my unit on in an open area for a while, updating my unit's software to the newest version, and I've made sure the measurements are in Deg/Min.mmm and Datum is WGS84. Is this normal or should I be expecting more accuracy than 150-200 feet? Quote Link to comment
+GOT GPS? Posted September 4, 2003 Share Posted September 4, 2003 If it is way off, even in Large Metro-Areas then there may be a problem, but usually its the mapping program. The new SporTrak Topo GPS being only 108 Megabytes for the BaseMap, may have those same map problems for your area. With all the different Mapping programs and GPS units out there, the best Mapping is City Select Deluxe for Garmin. This Mapping program is about 1.5 gigabytes, and quit accurate. This is just my experience only, but I do have Magellans and Mapsend too. Quote Link to comment
Jmurman Posted September 4, 2003 Share Posted September 4, 2003 I am running into the same problem with my Platinum. Off by about 150-200 ft. Quote Link to comment
TxFilmMkr Posted September 4, 2003 Author Share Posted September 4, 2003 So the coordinates listed should be accurate, right? It's the map that's the source of error? Quote Link to comment
Mikeomni1 Posted September 4, 2003 Share Posted September 4, 2003 It's the map. Not the GPSr. My ST MAP shows the location of my house 1/4 mile East of where it really is. Take the map display with a grain of salt. Regards, Mike Quote Link to comment
+quakemap Posted September 4, 2003 Share Posted September 4, 2003 If in doubt, load your track log into a real mapping program (like QuakeMap :-) - the aerial photos are very well aligned with coordinates, and you will see that you actually have traveled the road, not the nearby bushes http://www.quakemap.com - redefining Easy... Quote Link to comment
Neo_Geo Posted September 4, 2003 Share Posted September 4, 2003 Same problem with Garmin's Roads & Recreation 3.03. When traveling up my street, it shows my tracks being right between my street and the next one over. When I have MetroGuide 5 loaded, my tracks are dead-on with every road I've traveled. Gotta love that NavTech® data! Quote Link to comment
+Renegade Knight Posted September 4, 2003 Share Posted September 4, 2003 According to my GPS I'm next door in the shower with my neighbors wife. Sometimes this map inaccuracy problme isn't too shabby. GPS maps tend to be vector maps. (Line based instead of picture based because it takes less memory). Vector maps often have inaccuracy due to being made into a vector from a picture/map/photo. Add that into the limited accuracy from dealing with such a large scale (the entire nation) on a mass basis and accuracy becomes off somewhat. That's my best SWAG. Quote Link to comment
Overland1 Posted September 4, 2003 Share Posted September 4, 2003 quote:Originally posted by Renegade Knight:According to my GPS I'm next door in the shower with my neighbors wife............... I did a GPS track while mowing the lawn (GeoMowing) and one of the tracks showed me going across the street to the neighbor's house. The good news would have been that she is single; the bad news is that I am not . There are occasional errors that just seem to happen... the great mysteries of GPS. I Roger your vector, Victor...... Over. Quote Link to comment
+raouljan Posted September 4, 2003 Share Posted September 4, 2003 wait a minute!!!! are you telling me that there is a button on my GPSr that will put me in my neighbor's shower with his wife?????????????????????????? WHICH ONE? >Personally Responsible for the Recovery of .00244% of the Benchmark Database!<--watch this number! Quote Link to comment
+apersson850 Posted September 4, 2003 Share Posted September 4, 2003 From the "make your own maps"-attempts I've understood that Garmin's map objects are placed on a grid in the data base. The granularity of this grid determines how precisely objects can be placed. High resolution maps, like MetroGuide, have a substantially finer grid than the basemap in the unit. Hence, the basemap can't even be that exact, even if all data would be perfect. Which it isn't. Around where I live, there are deviations up to 500 meters. The Garmin MetroGuide maps allow a feature called "lock on road". If you are travelling at a speed that indicates that you're in a vehicle (or even if you have been travelling at such a speed) and you are near a road, and you are moving in the general direction of that road, it will tweak your position a little. Enough to place you on the road, that is. This is why MetroGuide maps seems to be so good. The "lock on road" feature masks both positioning and map errors, at the same time, if necessary. Anders Quote Link to comment
Jmurman Posted September 5, 2003 Share Posted September 5, 2003 where can I get the Metroglide maps for my Platinum? Quote Link to comment
+Search1128 Posted September 5, 2003 Share Posted September 5, 2003 Raouljan, your neighbor has more than one wife??? If you have to ask which one then of course pick the best looking and best performer of the lot... Quote Link to comment
TxFilmMkr Posted September 5, 2003 Author Share Posted September 5, 2003 Thanks for all the help! Quote Link to comment
Neo_Geo Posted September 5, 2003 Share Posted September 5, 2003 quote:Originally posted by Anders.:The Garmin MetroGuide maps allow a feature called "lock on road". If you are travelling at a speed that indicates that you're in a vehicle (or even if you have been travelling at such a speed) and you are near a road, and you are moving in the general direction of that road, it will tweak your position a little. Enough to place you on the road, that is. This is why MetroGuide maps seems to be so good. The "lock on road" feature masks both positioning and map errors, at the same time, if necessary. Anders I don't think that "Lock On Roads" is specific to MetroGuide - I think it's available with just the basemap, but I'm not sure. I'm pretty sure that it's available with WorldMap. I AM DEAD-SURE that the feature is turned off on my unit! Still, the accuracy of the NavTech® maps is amazing! quote:Originally posted by Jmurman:where can I get the Metroglide maps for my Platinum? MetroGuide is only works with Garmin units. Sorry. Quote Link to comment
+apersson850 Posted September 5, 2003 Share Posted September 5, 2003 quote:Originally posted by Neo_Geo:I don't think that "Lock On Roads" is specific to MetroGuide - I think it's available with just the basemap, but I'm not sure. I'm pretty sure that it's available with WorldMap. You are pretty wrong. Anders Quote Link to comment
Neo_Geo Posted September 7, 2003 Share Posted September 7, 2003 quote:Originally posted by Neo_Geo:I don't think that "Lock On Roads" is specific to MetroGuide - I think it's available with just the basemap, but I'm not sure. I'm pretty sure that it's available with WorldMap. quote:Originally posted by Anders.:You are pretty wrong. Anders I'm actually PRETTY RIGHT! I just erased my MetroGuide maps and uploaded 7.99MB of WorldMap data to my Legend, and guess what... "Lock On Road" is still there! If you look in the Legend manual on page 14 - the 24th page of the Adobe Acrobat version, it says "available only if MapSource Data is loaded". I'm pretty sure WorldMap qualifies as MapSource. So [This message was edited by Neo_Geo on September 07, 2003 at 05:01 PM.] Quote Link to comment
+mrp Posted September 7, 2003 Share Posted September 7, 2003 quote:Originally posted by Neo_Geo:I'm actually PRETTY RIGHT! Nope.. you're wrong, you just think you're right. The Lock-on-road flag is available whether or not the maps you have loaded will support it. I have a legend with both US Topo and R&R, and though I can check the little box on my legend that says "lock-on-road".. it doesn't actually modify my position so that I'm on the displayed roads. However, when using the maps from CitySelect NA (I also have a V), the lock-on-road feature will actually cause my little position icon to jump to the nearest street (within about 200 ft. or so.) So.. while the option is present even for the basemap, it doesn't do anything unless the loaded maps support it, and that (seems) to be true only for MetroGuide, CitySelect and CityNavigator maps. I've learned never to question the wisdom of Anders. It wouldn't surprise me to learn that he has secret access to Garmin internal documents and information. He's never wrong. -- Pneumatic Quote Link to comment
+apersson850 Posted September 8, 2003 Share Posted September 8, 2003 I'm sitting here, with a blushing red face. Could be that it's either due to the nice comments from Pneumatic, or that I have a severe cold, with high temperature and all. I'm sorry I mislead you somewhat, Neo_Geo. It's exactly as Pneumatic describe. You can always select "lock on road", but it will make no difference unless you have a map that supports it. I've only tried MetroGuide, which does support it, but I'm under the impression that it works with all maps that support autorouting too, i.e. City Navigator and City Select. The latter two aren't that frequently used in neither the Vista nor the Legend, though, since they can't make any use of the autorouting attributes on these maps anyway. So, you're right, Neo_Geo, the "lock on road" option is there, but I and Pneumatic are also right, in that it has no effect with WorldMap. Anders Quote Link to comment
Cybo Posted September 8, 2003 Share Posted September 8, 2003 Dang, this topic adds doubt into my mind about getting a magellan now. :/ Quote Link to comment
+quakemap Posted September 8, 2003 Share Posted September 8, 2003 Get a Garmin. At least when your wife will want to check your track logs, she will be happy to find you in all the right places. That's if you stick to aerial photo software of course (you are not in doubt about getting QuakeMap, are you? :-) P.S. Garmin tracking seems to be more smooth on the map because the unit samples position at a higher rate. My Garmin eTrex Vista beats Magellan SporTrak Pro hands down in this respect, but coordinates reported when static are pretty much the same on both units. http://www.quakemap.com - redefining Easy... Quote Link to comment
Cybo Posted September 8, 2003 Share Posted September 8, 2003 1) I don't have a wife, im 14 years old 2) But of course, i already have QuakeMap 3)The only reason i was going for the STMap is because it can recieve a stronger signal than the legend, which apparently has trouble in cars and under trees (where the STMap does not). But if the STMap has problems with staying on the streets.... :/ Quote Link to comment
+apersson850 Posted September 8, 2003 Share Posted September 8, 2003 Better sensitivity doesn't necessarily have to do with which brand you choose. Quad helix antennas are generally better, but can be found in Garmin units as well. So, if you get a GPS V or a 76S, you can have both excellent sensitivity and stay on the roads! Anders Quote Link to comment
Cybo Posted September 8, 2003 Share Posted September 8, 2003 Yep, but they're a little out of my price range. The most I'll be able to spend is probably $269CDN for the legend or the STMap. Quote Link to comment
victom Posted September 11, 2003 Share Posted September 11, 2003 I had a problem with my GPS not matching a topo map. I found out I was using the wrong map Datum. Our fellow geocachers use World Geodetic System 1984 (WGS 84). Many/most of the US topos use North American Datum 1983 (NAD 83) or even NAD 27. This may help correct the problem. Make sure your GPS matches the MAP. Quote Link to comment
ronnesti Posted September 24, 2003 Share Posted September 24, 2003 MapSend Streets and Destinations is not dependable for point to point navigation - depictions on the map are up to 1/4 mile misplaced. It is little more useful than a paper map - don't have to refold it . Thales says new MAPSEND DIRECTROUTE mapware will be useable for accurate turn-by-turn navigation. Estimate out in Oct/Nov - shooting for pre-Christmas market. They acknowledge that MapSend S&D is not very good - lots of complaints - they blame their map supplier - sometimes it is right on, but you don't know where. Quote Link to comment
gm100guy Posted September 24, 2003 Share Posted September 24, 2003 I find my old gm100 maps do not match the road and always laugh when I am driving near a lake on a highway and my car is shown in the lake. The Mapopolis on my palm when hooked up to the gps seem to be more accurate. But when I plot my position on my top map program it matches most of the time to my location. gm100guy http://members.rogers.com/gm100guy/cachepage.htm Ontario geocachers http://groups.msn.com/GeocachinginOntario/homepage Quote Link to comment
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