Co-ordinate help

Hi guys

 

I need some help here.

I am going to be on site logging approximately 400 waypoints using a Garmin GPS.

I have a dwg map of the area so it should just be a case of importing the points from the GPS device.

My question though is how to match the different co-ordinate systems.

IE The GPS uses the degrees and minutes while CAD uses X and Y.

How do I drop them at the correct co-ordinate in Acad? Or am I misunderstanding how that works?

 

Thanks

Rob

PS: I do have Mapsource if that is part of the solution.

Take a look at this thread - it deals with how to draw in minutes and degrees... when I read your question that might not be the answer here though. Depends on what kind of output you get from the GPS-device - what can it give you?

You do not say what model Garmin GPS you are using.

 

With my handheld model, I can go into the Navigation Setup menu and choose the Position Format (DMS or grid) and Map Datum. You want to set a datum that gives you the same coordinates as your map, and life is very easy then.

Thanks Tiger but as you suspected it didnt solve my problem. Please read below for a better explanation.

 

eldon - Ok I have set both Mapsource and the Garmin (GPSmap 60CSx) Map Datum to WGS 84 which is what the Garmin was set to (and its been used for this exact purpose before so must be correct)

GPS and Mapsource Position format is set to South African Grid.

 

When I take a position reading on the GPS the co-ordinate given for my office

is ...

31 Y0009818

X3301473

 

When I download the Waypoints from the device to Mapsource, the co-ord given for the office in Mapsource is again ...

31 Y0009819

X3301473

 

I then save the Mapsource file as a dxf and open it in Acad, but the co ordinate given is ...

X = 296943.0000 Y = 6697999.0000

 

I did copy the marker from the dxf and drop it onto a "co-ordinated" site map of the area and drop it on there and its way off.

 

I presume I was right to save the Mapsource dxf using UTM co-ordinates and not Decimal right?

 

 

What am I missing?

I have never used these sort of techniques, but until you find the proper solution, I would move the Waypoints as a unit, until one point agrees with your base map.

 

Sorry not to be able to give the definite solution.

Having just had a quick look at the Garmin website, are you up to date with all the download programmes, as there was a problem when the DXF output was not using the same Map datum.

Most likely not, could I ask you to post the link here?

10 points for effort Thank you

This is a link to the Garmin Mapsource Update and Download.

 

Hope you can find something useful.

Thanks eldon. Interestingly, yesterday I allowed Mapsource to do its own search for updates and the latest it could upgrade to was V 6.15.11.

Ive begun downloading V 6.16.2 and will try again. Will report back.

Ok no luck. The points are still not falling into the correct co ordinates. Can anyone think why?

 

What I did was take 2 more waypoints so I now have 3 different points around the city and when I input these to my drawing they do form the correct arrangement in relation to eachother but they are waaay out of position in relation to my layout.

 

I have to sort this out.

I would expect the points to be spatially correct, but if the Waypoints are correct in the GPS, but the DXF output is waaaay out, then the DXF output is screwing up.

 

Perhaps they have not got to grips with the problem with the Map Datum in South Africa. Ask Mapsource why it doesn't work properly, or demand a rebate