Questions tagged [polyline-creation]

Used for questions about making polyline features

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27 votes
5 answers
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Nearest distance between point and line layers in QGIS

I have two layers, a line and a point layer. I need to make a line layer which connects all the points to the nearest line feature. How can I do that? Is there a plugin available for QGIS? This is a ...
Frodo's user avatar
  • 2,407
34 votes
1 answer
10k views

Drawing perpendicular lines in PyQGIS

I have a situation like this: What I need to do is to connect each point to every line that is at most, let's say 200 m, away from the point. In other words, I need to draw a perpendicular line from ...
PeterBorook's user avatar
16 votes
4 answers
39k views

Transforming polygon to linestring in QGIS

I have a polygon, imported from a shapefile in QGIS. I would like transform it to a linestring instead so I can save it as a GPX file later. How can I transform a polygon to a linestring in QGIS?
Jonas's user avatar
  • 2,251
53 votes
8 answers
19k views

Switching line direction in QGIS

I would like to be able to swap the direction of a polyline/line in QGIS. I made a custom tool to do this in MapInfo, however I can't seem to find anything for QGIS. Does anyone know of a tool to do ...
Nathan W's user avatar
  • 34.7k
8 votes
6 answers
3k views

Creating all possible line segments between all points using QGIS

I want to connect all points in a point feature with every possible line segment using QGIS. For example, how a pentagon has five points with ten line segments connecting them all to form a pentagram ...
qu4ntumrush's user avatar
41 votes
6 answers
120k views

Drawing lines from points in QGIS

I have a point layer and need to draw a line passing through or in the vicinity of the points (up to 0.5m distance between the point and the line). The nodes of the line will receive the attributes of ...
H.Wiener's user avatar
  • 1,009
6 votes
4 answers
3k views

Generating line segments between all points using QGIS

How do I create a vector layer with a network of line segments drawn between every point in another vector layer? Basically, I am trying to create something similar to a hub/spoke network, except that ...
Nick_W's user avatar
  • 565
25 votes
6 answers
69k views

Converting polyline to polygon in QGIS

I have a shapefile with city areas, but unfortunately the shapefile only contains single lines. The shapefile looks like this: I want to convert those lines to an area-polygon shapefile in QGIS. I ...
Mark White's user avatar
19 votes
4 answers
7k views

Creating one-sided buffers or parallel lines in PostGIS?

I'm looking for a way to create so-called one-sided buffers or parallel lines in PostGIS. Example: 1. buffer, 2. one-side, 3. both-sides I've found some discussion on the mailing list from 2009 and ...
underdark's user avatar
  • 84.1k
25 votes
9 answers
46k views

Merging lines with slightly different endpoints in QGIS

In QGIS, I have two lines. The endpoints are near each other, but not quite aligned. I'd like to turn the two lines into one, with the two endpoints merged into midpoints. The closest I've been able ...
Evan's user avatar
  • 1,103
20 votes
4 answers
15k views

Creating Isochrones in QGIS

In QGIS I have tried to create isochrones around points for quite some time. Is there any option to create isochrones on the GUI in QGIS? I know how to create them using pgAdmin (using e.g. @underdark'...
groc's user avatar
  • 201
18 votes
0 answers
8k views

Creating trade flow maps in ArcGIS for Desktop (or any free software)? [duplicate]

I am trying to represent trade flows on a world map where the size and direction of arrows indicate the exports/imports of a given country. This type of map is commonly found in magazines and ...
relima's user avatar
  • 2,810
13 votes
3 answers
6k views

Connecting line features and determining the length of the longest line

I have a line feature (see image) representing a river that I created using the Stream_to_Feature tool. The attribute table contains several records representing different lines - the problem is the ...
Radar's user avatar
  • 10.7k
19 votes
2 answers
10k views

Finding tunnel center line?

I have some map files consisting of 'polylines' (each line is just a list of vertices) representing tunnels, and I want to try and find the tunnel 'center line' (shown, roughly, in red below). I've ...
sje397's user avatar
  • 291
15 votes
3 answers
30k views

Finding line length while editing in QGIS?

I am using QGIS. I would like to know if there is any way during the editing phase of a vector (line or polygon) to know the length of the line (total and partial) that is being created?
user4756's user avatar
  • 151
11 votes
4 answers
6k views

Creating arcs between two points in ArcPy?

I've been working on an python script automating the visualization of live point data. I have a table with two coordinate pairs. I'd like to connect these two point with an arc of a circle or similar (...
Pixel's user avatar
  • 586
13 votes
4 answers
4k views

Calculating line with the longest distance inside polygon in QGIS

I want to calculate the "diameter" of polygons in QGIS. The "diameter" is defined as the distance between the two most distant points of the polygon. I couldn't find a fitting ...
gis_student's user avatar
12 votes
5 answers
13k views

Convert XY points to a line?

Someone mistakenly saved a GPS track as waypoints and then sent them along to me in a .csv file. They want a line back (shapefile). What's the simplest method to convert this to a line? Available ...
matt wilkie's user avatar
  • 28.2k
8 votes
3 answers
4k views

How to create spider diagrams (hub lines) in PostGIS?

I'm rather new to PostGIS but I have done a lot of reading. One thing that I have been searching for is a function that allows users to create a "spider diagram" (also called "desire lines" or "hub ...
RyanKDalton's user avatar
  • 23.1k
7 votes
2 answers
4k views

How to create an offset polyline in arcpy?

I am trying to create an offset polyline using arcpy, identical to the function in ArcObjects (constructoffset). After trying to access ArcObjects in arcpy, which I found difficult for those not well-...
ndimhypervol's user avatar
5 votes
1 answer
3k views

Creating line layer with features using PyQGIS

In QGIS GUI, a line feature is created using this icon How to create a line with a fixed distance from a vector layer using PyQGIS. This my example: from qgis.core import * from qgis.PyQt.QtCore ...
leotv's user avatar
  • 439
2 votes
1 answer
1k views

Joining many points with lines in QGIS

I'm working with QGIS 3.4.3 and have a list of addresses (1500ish) that I need to map into lines. I have a CSV file having a start and end of each street and also have the same list separated in two ...
Juker92's user avatar
  • 23
27 votes
6 answers
23k views

What tools in Python are available for doing great circle distance + line creation?

I need to use Python to create a great circle distance -- both a number, and preferably some kind of 'curve' that I can use to draw in a client-side map. I don't care about the format of the curve -- ...
Christopher Schmidt's user avatar
16 votes
2 answers
7k views

How can I make a polyline wrap around the world?

I am using leaflet maps to create a representation of a round-the-world challenge. I would like to add a polyline which heads east from tokyo and then appears west of south america on the map - but ...
codecowboy's user avatar
11 votes
2 answers
2k views

Converting polygon to lines without duplicate edges?

This seems like it should be easy, but I'm not figuring it out: How do I convert a polygon layer into a line layer representing the polygon edges, where each edge belongs only to a single feature (or ...
Nathan's user avatar
  • 1,294
10 votes
1 answer
3k views

Making radial flow map showing curved lines over short distances (20km) using ArcGIS for Desktop?

Esri have provided instructions on how to make a radial flow map but I think the curved lines will only be produced over a long distance, like half the globe. For short distances (20km) a geodetic ...
ndthl's user avatar
  • 604
10 votes
1 answer
6k views

Split polyline by point using 'sf' package in R

I'm learning the sf package in R and would like to locate about 450 sites along the nearest reaches of a river network and to obtain the upstream and downstream distances along the reach where the ...
bcaradima's user avatar
  • 827
9 votes
3 answers
2k views

Finding longest straight line within polygon in QGIS

I'm looking for an algorithm to draw max distance straight lines contained in a polygon (without crossing polygon boundaries). How can I perform it? As you can see some polygons are very oddly shaped. ...
Michael Sousa's user avatar
6 votes
4 answers
2k views

Drawing lines to nearest points in QGIS

I have two point layers, one with telecom towers and another with secondary schools. I have used the NNJoin Plugin to find the nearest tower from each school, and calculated the distance between. The ...
olofhess's user avatar
6 votes
3 answers
878 views

Creating multiple separate vector lines from list of coordinate pairs in QGIS

I'm a QGIS user with 2 years of experience but I don't know how to do this task easily. I'm on QGIS 3.10.6 A Coruna. I know how to import CSV coordinate points and then convert them to a vector using &...
Paul's user avatar
  • 73
4 votes
2 answers
2k views

Creating input node file for v.net.salesman in GRASS

I have imported the line vector layer and point vector layer (12 points) to GRASS using v.in.ogr. Now I want to use v.in.salesman to find the shortest path between these 12 points, but I couldn't ...
Hariharan Murali's user avatar
3 votes
2 answers
1k views

Fixed distance between two contours in QGIS

Is there a possibility in QGIS 2.14.1 Essen, when you select a contour line and give a fixed length of line, this line connects automatically to the next contour lines? I have two other questions on ...
Frodo's user avatar
  • 2,407
18 votes
5 answers
20k views

Mapping matrix of origins and destinations in QGIS?

I have a central point on a map, and I have other points in a separate layer (the location of a venue, and the origin cities of the venue visitors). Is there a plugin which would generate output ...
normis's user avatar
  • 629
14 votes
3 answers
12k views

How to undo misclicks while drawing a polygon or line in QGIS?

While drawing some large polygons or long continuous lines in QGIS and I tend to misclick. Then everytime I misclick, I don't find a way to undo that last point (or several of the last points) and ...
simskopf's user avatar
  • 273
9 votes
2 answers
2k views

Scriptable alternative to ArcScan (particularly vectorising lines within tolerances)?

Sadly the answer to Can you access ArcScan from a python script? suggests that it is not possible to script ArcScan from within a python script. Therefore, does anyone know of any alternatives to ...
robintw's user avatar
  • 4,006
8 votes
1 answer
5k views

Creating polygon from exterior points using PostGIS?

How to convert points data to polygon, so as to form polygon from exterior point as shown above
user28344's user avatar
8 votes
2 answers
2k views

Building the shortest route through all points in QGIS

How to build the shortest route through all selected points, starting from a given point? Which plugin to use? There is a point layer and a linear layer for all routes between points.
Wawr's user avatar
  • 89
5 votes
4 answers
1k views

Creating line layer from point layer with start and end attributes in QGIS

I have a CSV file that contains attributes for a start node and end node of a pipe in a single record. This is data collected in the field, so the inspector captures the lat/long at each end of the ...
CEL-ma's user avatar
  • 1,015
5 votes
2 answers
3k views

Densifying polyline according to specific length using QGIS? [duplicate]

I am using QGIS 1.8.0 I would like to densify a polyline according to a particular length of segment (ex. 200 m). I know it is possible with other GIS software. Is it possible to do this in QGIS?
Francesco's user avatar
5 votes
2 answers
12k views

How to write a script that will automatically draw lines from one point to multiple destination points? (ArcMap 9.3)

I need to create lines from an airport to numerous destination locations. The destinations change often, so drawing them manually becomes tedious. I want to create a script that will draw them ...
Tanner's user avatar
  • 7,375
5 votes
3 answers
3k views

Determining the longest side of polygon in QGIS

Is there a possibility to determine the longest side of a polygon with QGIS? As I need to do that for hundreds of polygons I would prefer an automized method (like a plugin). So far my idea was: ...
ragavendra's user avatar
5 votes
2 answers
436 views

Creating line between point layer and line layer in QGIS

My goal is to create a line layer that is derived from the distance between a point layer and a line layer. An example could be using a line layer representing a road and a point layer representing a ...
sudofizz's user avatar
  • 195
4 votes
1 answer
912 views

Creating lines between points within distance in QGIS

I have a point layer and I'm Looking for a tool which connects every point of the layer with each other. Ideally, I can give a distance and the number of Connections for each point. The following ...
DGIS's user avatar
  • 2,527
4 votes
2 answers
2k views

Drawing lines between points in QGIS

I am doing a research project for which I need to find an effective way for drawing lines between a number of points along a square. I need there to be a line between every point on the square in ...
Klaus_Asbjorn's user avatar
3 votes
1 answer
2k views

From trajectory of GPS points to multiline segment?

Given a trajectory as a sequence of GPS points I would like to create a smooth linestring representing a path where a car drove. The data is stored in postgresql: the input trajectory in a table, ...
arthur's user avatar
  • 191
3 votes
3 answers
3k views

How to convert points to lines?

I want to convert these points to lines, however they are not sorted sequentially along a line (by ID or FID), i.e. the converted lines zig-zag across the obvious trail of points. How can I join ...
val's user avatar
  • 631
3 votes
1 answer
1k views

Using points2one plugin in QGIS

I downloaded the points2one plugin and tried many times to connect points to a line, but it never worked. Is there something that I set wrong? I tried the answer, but it has been running for 10 ...
Jack's user avatar
  • 113
3 votes
1 answer
3k views

Merging overlapping lines into one line. QGIS

I have a shapefile with multiple perfectly overlapping lines. Each line represents traffic at a certain point in time. I would like my output to have only one line but with the attributes from all ...
Vincze Istvan's user avatar
2 votes
3 answers
642 views

Connecting thousand of points in QGIS

I have thousands of points generated along river channels. I am trying to connect these points based on distance. Furthermore, I tried "Join attributes by nearest Points" and "Geometry ...
Bo Wang's user avatar
  • 69
1 vote
1 answer
2k views

Creating polyline which is average of multiple other polylines?

I am trying to use ArcGIS for Desktop to create an "average" polyline from several lines. For example if you have multiple hurricane paths and would like to plot the average position of all of the ...
Nava F's user avatar
  • 11