Questions tagged [line]

A set of ordered co-ordinates that represent the shape of geographic features too narrow to be displayed as an area at the given scale (contours, street centrelines, or streams), or linear features with no area (county boundary lines)

188 questions with no upvoted or accepted answers
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348 views

how to buffer a line with varying distances associated with directional quadrant with open source GIS?

I would like to buffer a set of lines with different distances to the NW, SW, SE, and NE. I have the distances stored in four attribute fields that correspond to the direction the buffer should be ...
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50 views

Snap LineStrings considering direction in QGIS 3

I have 2 projected shape files: Roads (red) and public transit routes (blue): I want to snap the PT routes to the roads, but because of inaccurate marks sometimes the routes are snapped to the wrong ...
4
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1answer
159 views

QGIS how to handle circular but non-closed lines

I use QGIS 2.18.3 and I have a shapefile with around 30,000 lines and a lot of invalid geometries. It is imported from a CAD project. I managed to solve most of the invalidities with the break ...
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1k views

How to join segments of a line in QGIS?

I have lots of different lines composed of hundreds of segments in a Shapefile. I would like to join them spatially where every start (or end) point of a segment correspond exactly (or within a range ...
4
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73 views

Loop distance point PyQGIS

I have a .shp of lines where I'm able to calculate the sum of segments length but I'm trying to put a point at a given distance in meters. The problem is it puts a point at every segment. When I give ...
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72 views

“Merging” 2 layers of LineString with splits at intersections

I would like to "merge" 2 networks of lines and these lines need to be split when they intersect. With pictures it should be clearer : What to do: if a black line intersects a red line, they should ...
4
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322 views

Merge line segments by length (in QGIS)

I have a layer containing line segments which are connected by their endpoints (e.g. as within a street network). I'd like to merge (union) polylines within this layer into one feature until following ...
3
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0answers
25 views

How to eliminate lines that are added when “join multiple line” plugin is used?

I'm new in QGIS. I have three road shapes. If I merge them, I cannot use "network analysis" (shortest path) because the merged lines are not continuous. I tried to use "Join Multiple Lines" and, ...
3
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59 views

How to create equidistant points along lines (network)?

I am trying to create points at every X meters along a set of lines that represent a network. As suggested in QChainage doesn't place points evenly along dissolved lines I managed to this ...
3
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0answers
72 views

Drawing lines for every row from a table

I would like to make a map showing all the train trips made by different users. I know how to make the difference between a single trip on a traject and many trips by using opacity. For now I have ...
3
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1answer
242 views

Density map of pedestrian paths and footways in QGIS

I need to identify public places within pedestrian areas in London, so I need to calculate the density of both pedestrian links and footways. I have classified my data according to the categorization ...
3
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0answers
67 views

Given a line find whether another line is along side, N,E,S,W or not

I have a shapefile representing roads (Black) and I need to know whether another line object (Red) is to the side of it. Including the orientation between them, to define whether the Red line lies to ...
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113 views

How to undo/redo drawing polyline

I want to draw a custom polyline using mouse click events in an AddIn.Tool project without esri's build-in interfaces eg. Rubberband, IDisplayFeedback or IShapeConstuct. I got problems pushing caches ...
3
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55 views

After dissolving lines, old node/vertex order does not reset, causing issues with chainage

In QGIS, I am trying to dissolve multiple segments of a river feature and then calculate chainage on the resulting single feature. However, it seems like the internal node/vertex order gets preserved ...
3
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0answers
337 views

Create a perpendicular line of points to another line

i have two problems over here. QGIS 1- I need to create a perpendicular line to connect multiple points to multiple lines but these lines have to follow a sequence of column. 2- And these ...
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0answers
261 views

Reorder Shapefile of lines for consecutive ordering (Assemble Lines into LineString)

I have a Shapefile containing segments of Lines/LineStrings: Unfortunately the order of the DBF attributed table is random. How to reorder the segments so entry #1 in the Shapefile will be "Segment ...
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0answers
38 views

How to make line id's on continuous order

I have a problem with numbering the line segments. I need to make line segment id's that have letters according to polygon areas (got letters for line segments already) and number according to ...
3
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143 views

How to display a line with fading transparency in qgis?

I have a straight line with two vertices, which I'd like to style. I want the style to be a fading line from start to end, so the transparency is gradually increasing from start to the end of the line....
3
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0answers
637 views

Troubleshoot with “Split selected features with selected line from another layer”

I am trying to use the "Split selected features with selected line from another layer" tool from the plugin Digitizing Tools in QGIS. Sometimes, this tool works with my shapefiles but sometimes it ...
3
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0answers
3k views

QGIS break polyline into line segments

In QGIS (2.14.3.) how do I break polyline features in their consisting (single)line features? I have tried the 'Explode lines' geoprocessing tool, but this destroys the whole polyline into very atomic ...
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1k views

In ArcMap, when using Add Surface Information, why are all avg_slope values positive?

I've got a polyline shapefile and a LIDAR elevation dataset. I've successfully used Add Surface Information (from 3D Analyst) to calculate the average slope (avg_slope) of each line segment. The ...
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1k views

Smoothing Lines in PostGIS

I want to smooth Lines in postgis, to be more specific, I want to smooth road data from OpenStreetMap. Basicly I thought of something like this scenario. This would be a possible road segment. I ...
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226 views

Quantifying polyline overlap

I have a set of regions and would like to quantify the degree to which the boundary of these regions are situated on/near rivers. I have turned the regions from polygons to polylines in arcgis 10.1 ...
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44 views

Isolating main polyline using QGIS?

I am trying to convert a line shapefile with branches into just one polyline, actually deleting every other diramation. Imagine something like this: :________|__________|____|||______ into :...
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0answers
34 views

Splitting line into two lines with GRASS GIS?

I converted a raster to polygon, after converting polygon to lines I have one line of the channel of a river which border a river. But I need to split this line in two lines: left border and right ...
2
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1answer
48 views

Split a polylines according to a specific point in R

I have 2 distinct spatial objects: on one hand I have a SpatialLinesDataFrame on the other hand I have a SpatialPointsDataFrame Considering one line and one point that intersects that line, I ...
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0answers
49 views

Spatial join by argument closest, but based on majority of vertices

I'm often working with different polyline datasets which represent street networks. One of the most common tasks I have is to join information from one layer to another. Often there are no mutual ...
2
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0answers
103 views

Shortest path between start and end point with many other points in between

Sorry if double post, but I haven't found this specific problem in the search function. I want qgis to show me the shortest path (direct) between many points with each point only is hit once. There is ...
2
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0answers
42 views

How to export a single feature (line) from multiple layers and export to individual layers?

I have multiple vector layers representing a time series. Each layer contains many lines each. I want to select a single specific line from each of these these layers and save it to another layer. ...
2
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0answers
119 views

Is there a keyboard shortcut to draw a perftectly straight line?

In most programs, when you have a line tool, you can hold control or shift and it will let you draw a perfectly vertical or horizontal line, sometimes it the tool will snap at 90 degree angles. How ...
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216 views

Extend line to specific point

I have a line layer which is cut at the level of the point layer, I want it to be connected at the nearest point while saving the forme ( just adding the missing part the that line without moving it)...
2
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0answers
92 views

Clipper: Split polygon layer with line layer - generates empty layer

I am using QGIS 2.14.3 Essen. I wanted to split several polygons with several lines. Both layer are in GK4 coordinate system (used layers generated by: QGIS right-click on layer -> Save as... ) and ...
2
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0answers
187 views

split lines into segments without creating new layer in QGIS

How to split line objects into segments/multiple objects based on either polygons or lines without creating a new layer? The problem is clarified in the picture below. I need the green line to be ...
2
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0answers
87 views

Converting polyline to polygon without 'Feature to Polygon'

I am attempting to create a script tool to automate some processes at work. Part of this process was to manually cut (using Cut under Editor) a buffer. My approach to this has been to try and split ...
2
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0answers
428 views

R coordinates on line nearest to point - multiple points

In R, I have a collection of points (~15,000) within a polygon. For every point, I want to calculate the location on the polygon boundary nearest to the point's location. I'm not bothered about the ...
2
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0answers
218 views

R - Spatial Join Between SpatialPoints (GPS coordinates) and SpatialLinesDataFrame

I am working on a university project which combines data science and GIS. We need to find an open-source solution capable of obtaining additional information from a massive GPS coordinates dataset. ...
2
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0answers
387 views

QGIS: Select Lines within a polygon

I would like to select all lines within a polygon. I tried to do that with the clip-function, but it didn't work out (the resulting layer was empty). Do I have to select a particular setting before ...
2
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0answers
31 views

Why do new lines appear when transforming polygon into lines?

I'm quite new to QGIS, and I want to do something fairly simple, but I found something strange in my data. I want to transform polygons into lines, so I can apply the buffer function afterwards to ...
2
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0answers
161 views

Shortest path creation between two lines

I've a raster of temperature of a river, I'd like to extract values horizontally, so from bank to bank, shortest path. so basically extract pixel values along the red lines in the schema I did. What ...
2
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0answers
128 views

Determine percentage of parallelism of two parallel lines in QGIS/python

I'm trying to match some lines to each other and join attributes proportionally. Have a look at the image where S1 can appear in both A1 and A2. Let's say 30% of S1 is parallel to A1, and 15% of S1 is ...
2
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0answers
93 views

Railways usage - How to assign values to part of existing lines?

I am conducting a project about rail accessibility/capacity, working with railways/stations downloaded in R with Overpass. Manually I computed the number of trains for each lines and I would like to ...
2
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0answers
143 views

Split line into the different lengths from attribute table data

Is it possible in QGIS to split one line in one direction into multiple segments of varying length which I have in the attribute table? For example: overall line is 10 m long, in table I have data: 1....
2
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0answers
77 views

Combining points and polygons in Qgis

I´m trying to create a map that can be loaded into the program CityEngine as a shapefile. To create this map I have an excel spreadsheet that includes locations, in longitude and Lattitude, and ...
2
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0answers
138 views

How to measure orthogonal distance of line from point in QGIS?

As I am fairly new to QGIS I'm seeking your help. I'm trying to measure the distance between points in a point Layer P and the end of lines in a line layer L. In L there are two categories (attributes)...
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0answers
70 views

How to count near intersecting polylines and merge them?

I have a dataset with several polylines created by GPS points of car trips. I am trying to create a simple heatmap where roads with more traffic (where polylines intersect) get darker. I already ...
2
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0answers
1k views

Algorithm to simplify a Polygon/Series of Points to a given number of Points

I have a polygon (or let's call it just a series of points). I want to simplify it (reduce the amount of points) to a given number of points. Currently I use Douglas Peucker and try to guess the ...
2
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0answers
485 views

Showing marker upfront in OpenLayers 3 while drawing polyline?

I am drawing the polylines on the map and displaying few marker as well which is working fine but when the polyline is drawn marker is above the line I wanted to know how to show the marker upfront ...
2
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0answers
123 views

Split Polyline QGIS - Too Many Resultant Features

I'm trying to split a single polyline into 2 polylines (I have lines that loop back on themselves, and I need to split each one into two lines: one for going, and one for coming back). When I use ...
2
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0answers
229 views

Equal distance points on polylines

In QGIS 2.10.1 I want to create a point layer out of my polyline shapefile and all the points shall have a fixed distance (in meters) while I use WGS84 as coordinate system. So what do I use for this? ...
2
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0answers
256 views

Connect two contour lines with calculated line length

Is it possible to make a plugin for QGIS like PEGGER for arcview 3.2? Problem is, how to make path over contour lines with a gradient in percent? Formula is: K= e*100/G*M ; K=10*100/0.08*10000=1.25m ...