[GIS] Arcgis 10: Point layer, polygon line layer, draw points to the nearest polygon point or other nearest line

pointpolygon

I have been using arcGIS for a while now but I often get frustrated with it 🙁

I have version 10.0 arcGIS and I'm have two layers

1) Point data (building locations)

2) a polygon shape file (outline of a continent)

A) I'm trying to find the nearest part of the polygon to the point data (nearest coastal point for the building) and draw a line between them forming a hypothetical pipeline…..

-> I have used spatial join and have a table of the nearest points but how to draw lines between those and the original points?

B) if these lines are close to each other or cross over, I want them to join up to form one line.

Any advice would be great here. All the options I tried are now either out of date or don't work anymore.

Best Answer

1) If you have an ArcInfo (Advanced) license, you could try Near (Analysis), Point to polygon

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00080000001q000000

Determines the distance from each feature in the input features to the nearest feature in the near features, within the search radius.

Optionally, NEAR_X, NEAR_Y, NEAR_ANGLE, and NEAR_FC fields can also be added to the attribute table of input features as explained in the near features and optional parameters entries.

Set the location parameter to LOCATION to get it to display NEAR_X and NEAR_Y in the output table.

2) Use Calculate Geometry to get the start_x and start_y coordinates of your input point features. Then it's a matter of using XY To Line (Data Management) to draw your lines from start_x, start_y to near_x, near_y.

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//0017000000tv000000

The basic idea

Create lines connecting each point to it's closest neigbour. You will get lines with gaps in between. To close the gaps, connect each of these lines with the closest point on the nearest neighboring line. Finally, connect each of these lines to the closest point on the nearest section of the street layer.

How to do it in QGIS: create lines with `Geometry by expression`

Create a line from each point to its closest neighbor using the following expression with Geometry by expression and replace points with the name of your point layer: make_line ( $geometry, overlay_nearest( 'points', $geometry, limit:=2)[1])

Each point connected with red lines to the nearest neighboring point:
Clean the output of step 1 using these four steps: i) apply Explode lines, ii) Delete duplicate geometries, iii) select all features and then Merge selected and iv) finally turn Multipart to single parts.

Connecting lines: each line should be connected to the closest point of the nearest line. Use this expression on the output of step 2 with Geometry by expression and replace Singleparts with the name of the layer from step 2:

 union (
     $geometry, 
     make_line (
         closest_point (
             $geometry,
             overlay_nearest( 
                 'Singleparts', 
                 $geometry, 
                 limit:=2
             )[1]
         ),
         closest_point (
             overlay_nearest( 
                 'Singleparts', 
                 $geometry, 
                 limit:=2
             )[1],
             $geometry
         )
     )
 )

Clean the output of step 3, repeating the four steps of step 2 above.

The red dotted line is the output from step 4:

Now you have to connect each resulting line to the street layer. Use once again Geometry by expression on the output of step 4 with this expression and replace street with the name of your street layer:

 union (
     $geometry,
     make_line (
         closest_point (
             overlay_nearest ('street', $geometry)[0],
             $geometry
         ),
         closest_point (
             $geometry,
             overlay_nearest ('street', $geometry)[0]
         )
     )
 )

See final output:

Best Answer

Related Solutions

[GIS] Draw line between points from multiple datasets

Get nearest neighbour on same or another layer to connect points by drawin a line in QGIS

The basic idea

How to do it in QGIS: create lines with Geometry by expression

Related Question

How to do it in QGIS: create lines with `Geometry by expression`