1

I am new to this so please be patient. I am working with a series of trail gpx files that I downloaded from the State of Michigan all but four of the files map perfectly. The four that are not, appear to be the right tracks, but they fall into the Atlantic Ocean instead of Northern Michigan. Is there a way to alter the gpx file to right the situation?

Here is an example of what I'm working with.

http://www.dnr.state.mn.us/mis/gis/tools/arcview/extensions/DNRGarmin/DNRGarmin.html" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.topografix.com/GPX/1/0" xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd"> MAKIB1 2012-01-30T11:00:23Z 1 1 2 3

  • Do you have a link to the files? – Mac Maclean Oct 16 '15 at 6:04
1

This sounds like a coordinate issue. You need to make sure that you're setting the points in the correct coordinate system because if not, you'll get an offset. When I first started doing GIS, all of my points were showing up near the Ivory Coast, even though I'm in Indiana.

Be careful, you might have a projected or geographic coordinate system. MOST open data sets are in WGS84.

  • If you got the coordinates from the State of Michigan, please look at the site below to read about the commonly used coordinate systems for the State of Michigan. As someone suggested, they may have put the data in another coordinate system and, working with a municipality in Indiana, we use State Plane Indiana East FIPS 1301 (Feet). If you want something quick, try the coordinate system I just gave you and if it's close in the region, then it's most likely the Michigan equivalent projected coordinate system. michigan.gov/documents/… – René Casiano Oct 19 '15 at 14:02
0

The file claims to have points at lat="4.14349103508591E-04" lon="-97.4895149007054" and that is definitely in the Pacific, and not Michigan. 45 / -85 would be ok for Michigan.

Since GPX only uses WGS84 by definition, you have no other way than to ask the data provider about it.

  • 1
    I guarantee that someone took lat/lon coordinates, assigned a projected coordinate system to them (most likely a UTM zone), and unprojected them. – mkennedy Oct 16 '15 at 16:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.