[GIS] How connect points with lines in QGIS

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I need to connect points with lines in QGIS. I am in this fresh out so I'm not sure how to do it and I need a little bit help with this. I read several posts and I tried to do something about it but unfortunately did not work out. So I would ask for a hint and error indication at what I do.

First: I have a couple of addresses in Excel (including city, street and number). I used a plugin (called geokoder navidata.pl) to apply them to a .shp file and I added this layer to program.
And now, I want to connect some of these points with lines to illustrate how someone has moved.

I tried to use several plugins (e.g. PointConnecter, Point2One, Point to path ) but failed every time.

I have about 1300 points and the line should be two times more (connecting will look like: point 1 to point 2, point 2 to point 3; point 4 to point 2, point 2 to point 5 etc.).

I have attached photo of what I need to do.

I have points (city, street, house number) and and their coordinates (X and Y) on points layer (.shp) and now I need to connect them using lines as follows:

First address -> address of meeting point -> Second address Third address -> address of meeting point -> Fourth address etc.

The meeting point is one point on the map (in the middle).

Could someone please explain to me how to do it, I tried: point2one, PointConnectr. It seems to me that I should do this by points2path but when I want to do, it gives me an error.

Best Answer

Use the Points2One plugin.

Install this plugin (Plugins->Manage and install plugins)
Follow the instructions for the plugin. Make sure to select line.
Save as geojson.

I often find I need to smooth my lines after connecting points. For this, search for simplification algorithms.

Related Solutions

QGIS – Linking Points with Lines for Display in QGIS for Better Visualization

You can connect the points using geometry generator. Let's say you have two points layers, where the fid is matching the potints in each layer you want to connect with a line. For demonstration, I just created two layers with 10 random points on each.

In one of the layers, add a symbol layer and use geometry generator for symbol layer type - see screenshot below. As geometry type, set LineString. Now you have to define the expression that generates your line (see below for how the expression should look).

The advantage is that the line adapts automatically to every change (adding or removing points, moving points to another place etc.) in realtime. And you don't need a separate layer. However, if you would like to make the lines permanent and store them in a separate file and show them in an own layer, you can paste the same expression to the geometry by expression algorithm (from processing toolbox).

The expression could look like this, just adapt to include the layer-name you use (instead of 'your_layer2' - layer names shold look someting like 'layer_2_d5d61a64_fe2d_44bf_a62e_1168bd89d4ea' - best select the layer from the expression editor):

make_line(
   $geometry,  
   geometry(
       get_feature_by_id( 
       'your_layer2',  "fid" )
    )
)

Explanation: Selecting layer 1, use make_line (point1, point2) to create the line. Point1 can be set to $geometry, thus for each feature on your layer1, you want to have a line starting from there. The line should go to the corresponding point on the other layer: to the feature on layer2 with the same fid. Thus use get_feature_by_id(layer,feature_id) and add the layer and the fid-field (if you just paste the field-name, it will take the field from layer1 - that is what you want, because the fid for layer2 should be the same as for layer1). Best use the column in the middle of the expression editor and select the entries from there (expand the headlines for map layers and fields and values). This returns you a feature. You have to use geometry(feature) to convert the feature to a geometry (a point, in this case). The parameter (feature) is the expression we just discussed before.

You see the two points layers, each in a different color. I added a label with the fid to show how the lines are drawn.

QGIS 3 – Manually Assigning Points to Line

You just need a field common to both the streets and points. Assuming your streets layer has a field with unique identifier, you can create a new field in your points layer (with a similar name) and enter the street identifier for each. Then you can easily use a join or a relation to link the data.

Streets layer with unique identifier:

Manually create a similar field in your points layer:

To add the attributes of the counting stations to the streets you can then make a join on the streets layer (Right-click layer name > Layer Properties > Joins)

Best Answer

Related Solutions

QGIS – Linking Points with Lines for Display in QGIS for Better Visualization

QGIS 3 – Manually Assigning Points to Line

Related Question