Anyone know how to use qGIS (free) software?

I have two CSV spreadsheets. One a list of about 22,000 points (that make up a track) and the other is 1200 points that are nearby (but no on) the track.

qGIS can produce a distance matrix that tells you which is the nearest (of the 22,000 points) to each of the 1200 points.

Anyone any ideas or help? I can mail you the two spreadsheets

C

There’s a strong QGIS community online, have a look for this.
You might be able to code something up by changing some shared code

I can do it not using qgis

I think this is close to what you want

I can do it and happy to help out – was it you I did this for awhile back?

Greg

Hi Greg,

yes it was. Then I sorted out how to do it. Now a few months have passed and I’m struggling o do it. I have done it and although the answers look right (in that the right points show they are closest to the right points) but the distance it gives looks way-wrong.

C

Units – check projection system and distance units

It also misses come points from the output results

c

Yeah, check the projection. I reprojected from wgs84 (lat/long) into EPSG 102005 (USA contiguous equidistant conic) otherwise the distance will be in decimal degrees.

Did you get it working?

Just back at it now, will let you know

C

So I gave up on this 🙁

I have about 1160 points that I want to know, for each one, how far it is off, to the nearest point, of a long trail. When I do it I have several problems. On the table it generates, some of the points are missing. Of the ones that are reported, sometime the distances look right but then I do it again and they are miles incorrect.

I’m stumped.

C

I’ll take a look if you want to email (email in profile)

That would be brilliant ebygomm. I’ll send the sheet(s)

thank you

I’ve replied from a different email address to the one on my profile so might need to check your spam folder.