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All,
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<div class="">Just some additional info/thoughts, I tried doing this a bunch of different times over the years, and the best method I’ve come up with for this type of processing is to dump into postgres/postgis and do everything via SQL. I actually needed
to be able to dynamically run a stepped analysis with varied cut-off distances to a line, and this worked out very well, and was easy to reuse for other projects over time, since all the functionality ended up being stored as a View into the souce DB table
data.
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<div class="">bobb</div>
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<div class="">On Oct 22, 2019, at 11:35 AM, Falk Huettmann <<a href="mailto:fhuettmann@alaska.edu" class="">fhuettmann@alaska.edu</a>> wrote:</div>
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<p class="MsoNormal"><strong class=""><span style="font-family: Calibri, sans-serif; color: rgb(255, 51, 51);" class="">Think Before You Click:<span class="Apple-converted-space"> </span></span></strong>This email originated<span class="Apple-converted-space"> </span><strong class="">outside<span class="Apple-converted-space"> </span></strong>our
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<div dir="ltr" class="">Hi there, Christoph,
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<div class="">generally speaking: I have another perspective about it and would approach your problem it in a different way:</div>
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<div class="">Instead of pre-defined cut-offs (which are circular reasoning and are often surprising when checked in real world and GIS)</div>
<div class="">I would simply run a 'proximity to' points vs line first. And then in the resulting proximity table set a cut-off, select accordingly and see whether</div>
<div class="">this achieves the outcome wanted.</div>
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<div class="">For pre-defined cut-offs, we call it usually 'geographic racism'. </div>
<div class="">Instead, we try to celebrate the gradient theory; when tested it often works better in real life.</div>
<div class="">Worth a test.</div>
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<div class="">Just an alternative thought to the problem at hand. </div>
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<div class="">Thanks, best</div>
<div class=""> Falk Huettmann</div>
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<div dir="ltr" class="gmail_attr">On Tue, Oct 22, 2019 at 3:26 AM Christoph Jung <<a href="mailto:jagodki.cj@gmail.com" class="">jagodki.cj@gmail.com</a>> wrote:<br class="">
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Thank you all for your answers. I played a bit with the nnjoins plugin, but Andrews‘ answer is exactly what I was looking for :)<br class="">
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Sincerely,<br class="">
Christoph<span class="Apple-converted-space"> </span><br class="">
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> Am 18.10.2019 um 20:50 schrieb Andrew McAninch <<a href="mailto:andrew@rabbit-troop.net" target="_blank" class="">andrew@rabbit-troop.net</a>>:<br class="">
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> You can do this in the field calculator with the refFunctions plugin. It gives you a function, geomnearest(), which will return the WKT geometry of the nearest line(or geomdistance() if you want to limit your search radius). Then use the closest_point()
function to find the nearest point on that line. something like:<br class="">
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> closest_point(geom_from_wkt(geomdistance('lines','$geometry',10)) , $geometry)<br class="">
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> Andrew<br class="">
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> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐<br class="">
>> On Thursday, October 17, 2019 11:51 PM, Christoph Jung <<a href="mailto:jagodki.cj@gmail.com" target="_blank" class="">jagodki.cj@gmail.com</a>> wrote:<br class="">
>><span class="Apple-converted-space"> </span><br class="">
>> Hello list,<br class="">
>><span class="Apple-converted-space"> </span><br class="">
>> Does QGIS has a function to calculate the nearest point on a line layer by a given point layer? In PostGIS i could query it with min(st_distance(...)) or st_closestpoint(...). But I miss such a function directly in QGIS (I just found the plugin Cloest Point,
but it has some issues...).<br class="">
>><span class="Apple-converted-space"> </span><br class="">
>> Sincerely,<br class="">
>> Christoph<br class="">
>><span class="Apple-converted-space"> </span><br class="">
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