[Qgis-user] Polygon next to road search term

[Jon]

Thanks David, When I go to intersect the buffered layer with the
polygon layer, what am I looking for?

Would it be:
Line Intersections
Intersection

In the Processing Toolbox and any settings that need to be set before
running, like iterate over each one?

Jon

-----Original Message-----
From: David Strip <qgis-user at stripfamily.net>
To: jonr at destar.net, Qgis-user at lists.osgeo.org
Subject: Re: [Qgis-user] Polygon next to road search term
Date: Wed, 14 Sep 2022 09:39:41 -0600

  My starting approach would be to take the road layer and buffer that out by some small distance - say 5 meters. (Note that you have to be working in a projected coordinate system for the buffer distance to have useful meaning.) I would then intersect the buffered layer with the polygon (lot) layer. The resulting intersections will be the overlaps between the buffered roads and the polygons. The attribute table will contain a list of all the intersections and each row of the table will contain the attributes of both the lots and the roads, so if the lots and roads have attributes with meaningful names, you will have a list of all lots that intersect roads and the names of the road it intersects with.
 
 You could also try extract by location from the processing toolbox. This would give you a layer of the original lots (polygons) that intersect some road, but won't tell you which road.
 
 On 9/13/2022 10:19 PM, Jon via Qgis-user wrote: 
> I would want the polygon to have road access. So you should be able to
> access the polygon firectly from a road. Just a corner touching may
> work but that would depend on an easement and I am having enough
> trouble just trying to figure out what I should be searching on without
> throwing that in as well.
> 
> So at this point, the polygon should be able to be accessed by the road
> line. So possibly 20' of the road line is touching the polygon.
> 
> -----Original Message-----
> From: David Strip <qgis-user at stripfamily.net>
> To: jonr at destar.net, Qgis-user at lists.osgeo.org
> Subject: Re: [Qgis-user] Polygon next to road search term
> Date: Tue, 13 Sep 2022 21:12:01 -0600
> 
>   Is a polygon "next to a road" because one (or more) edges of the polygon is exactly coincident with the road line? Or is it within some distance of the road line? These lead to different solutions, but unless your data is very precise, asking for the boundary to be exactly coincident with a road line is not going to be very robust.Does your road polyline feature have a road width? If so, does that factor into "next to"?
>  
>  
>  On 9/13/2022 5:26 PM, Jon via Qgis-user wrote: 
>  
> > I am trying to figure out if a property that is a polygon is next to a
> > polyline (road). I am not well versed with QGIS and every search I do
> > seems to tell me how to map a polygon onto a road or convert polylines
> > to a polygon. I am not sure what exactly I need to search on to find
> > some documentation on how to do what I am looking to do.
> > 
> > What should I be searching on to find if a property that has 4 sides
> > and is a polygon is next to a road? Is what I am trying to find called
> > something specific and that is why I am not finding?
> > 
> > Thanks for any help,
> > 
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