Anyone know how to ...
 

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[Closed] Anyone know how to use qGIS (free) software?

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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


 
Posted : 28/10/2017 4:59 pm
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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


 
Posted : 28/10/2017 5:18 pm
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I can do it not using qgis


 
Posted : 28/10/2017 5:21 pm
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[url= http://www.qgistutorials.com/en/docs/nearest_neighbor_analysis.html ]I think this is close to what you want[/url]


 
Posted : 28/10/2017 5:37 pm
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I can do it and happy to help out - was it you I did this for awhile back?

Greg


 
Posted : 28/10/2017 5:51 pm
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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


 
Posted : 28/10/2017 6:15 pm
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Units - check projection system and distance units


 
Posted : 28/10/2017 6:22 pm
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It also misses come points from the output results

c


 
Posted : 28/10/2017 6:31 pm
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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.


 
Posted : 28/10/2017 7:19 pm
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Did you get it working?


 
Posted : 29/10/2017 9:27 pm
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Just back at it now, will let you know

C


 
Posted : 03/11/2017 5:24 pm
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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


 
Posted : 04/11/2017 6:35 pm
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I'll take a look if you want to email (email in profile)


 
Posted : 04/11/2017 6:43 pm
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That would be brilliant ebygomm. I'll send the sheet(s)

thank you


 
Posted : 04/11/2017 6:47 pm
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I've replied from a different email address to the one on my profile so might need to check your spam folder.


 
Posted : 04/11/2017 8:34 pm

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