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)

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16
votes
2answers
3k views

How can I merge/collapse nearby and parallel road lines (eg. a dual-carriageway) into one single line?

I have a shapefile from OSM which contains all the roads within a city. Larger roads (like dual-carriageways) seem to have 2 parallel lines. I'd like to collapse / combine those into 1 line so I can ...
13
votes
4answers
3k views

Elevation profile 10 km each side of a line

How can I get an elevation profile for a band of terrain? The highest elevation within 10 km (on each side of the defined line) should be taken into account. I hope my question is clear. Thank you ...
11
votes
4answers
13k views

How to Partition Line into Segments using ArcGIS for Desktop?

I have a shapefile of U.S. states. I extracted the boundary between two states, resulting in a line segment. For example, the boundary between Georgia and North Carolina. Is there a way to further ...
11
votes
2answers
2k views

Moving points onto lines (~neighborhood)

I do have two vector layer, of which one is a point layer based on "events" by remote sensing and the second one is a line layer from local research. In my case these are earthquakes and tectonic ...
10
votes
4answers
4k views

Finding centrelines from polygons in QGIS?

I was wondering if there is a way to create centre lines from polygons in QGIS? I have a polygon layer, but ideally need the centrelines as a separate file.
10
votes
2answers
1k views

Creating a line (closest vertex to line)

I am working in reorganising our utility data. Two years ago, we have started collecting Private Service water line. We still have a lot of them to extract from old Record Drawings. I was ...
9
votes
4answers
45k views

How to create polygons from lines?

I am trying to create polygons from a line layer of lots and concessions (large blocks of land in rural areas). The lines are mainly grid style as they intersect mostly at right angles. I need to ...
8
votes
1answer
10k views

Draw lines from points in QGIS

(I found here similar questions but they all reffer to ESRI's programs, and I use 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 ...
7
votes
2answers
274 views

How to connnect two lines with different width so it looks good?

Simple question, how do you create a symbol with or without representation to connect two lines with different line width so it looks good? I need to have a smooth transition between the lines, ...
7
votes
2answers
174 views

Drawing line between points at specific distance in PostGIS?

I have a data of points along the streets, I would like to turn those dots into simple coloured lines. Any pointers what this problem may be called or any algorithms that can help me solve this? I ...
7
votes
3answers
3k views

A tool or way to Extend line by specified distance?

I have a purely aesthetic layer which has arrow symbols. Some aren't showing up right because the line is too small. I have selected maybe 50 records where I need to extend this line by a given number ...
7
votes
1answer
1k views

QGIS line style

I found the latest QGIS has a great tool to create complex styles, however looks like one small but very useful thing is missing, or I can't find it. I'm trying to create a line style something like ...
7
votes
1answer
1k views

Is there a way to automatically snap loose points of lines to close by vertices with Quantum GIS?

I have a vector layer of lines that were drawn with the snapping option off. I need to have them snapped but, there are hundreds of lines. Is there any solution to do this automatically or ...
7
votes
1answer
213 views

How to connect centroids of lines sharing the same intersection in QGIS?

I'm looking for a big help to accomplish the following task: I have this street network of the center of Turin (IT), composed by lines representing streets, and black points representing ...
6
votes
3answers
19k views

Converting multiple lines into single line using ArcGIS Desktop?

I've no idea if this is basic or what but I have this data that contains multiple lines (forming a polygon shape). I want to convert those lines (multiple - each with a start and end point) to a ...
6
votes
1answer
10k views

Create point in intersections of two layers

I have two layers. One of them is 'Road_line' and another one is 'forest_shape'. I want to create a point layer that has points in intersection of that layers. I couldn't find any tools for it.
6
votes
2answers
3k views

Checking "connectedness'' of line shapefile in ArcMap?

I inherited a line shapefile in ArcMap that is used to represent a road network. The problem is that the road network is pretty large and it is impossible for me to: Tell if the end of each line ...
6
votes
2answers
4k views

How can several vector layers have different controls, using Openlayers?

Using openlayers I have two vector layers. One layer is called lineLayer consisting of vector lines, and the other is called pointLayer consisting of points. When I hover on the lines I want to be ...
6
votes
1answer
7k views

Cut polygon shapefile by line shapefile

I have two shapefiles, a polygon shapefile (lake) and a line shapefile (boudary) I want to create a new shapefile "polygon to the north of the boundary" What tool can I use in QGIS or other free ...
6
votes
1answer
676 views

Filling a polygon with lines using Postgis

i need to calculate a specific distance in an area. The distance is calculated from parallel lines in a polygon, And i need to find out how many parallel lines (with x meters distance to each other) ...
6
votes
2answers
1k views

How to create line with exact same length over and over again?

I need to draw 30 meter lines in specific places. Ctrl+l is too annoying to do everytime. Is there a easy way to define specific same length for a line that I need to draw many times?
6
votes
4answers
375 views

How to avoid holes in polygons from lines?

I am trying to convert a dataset of lines that contains the coast of New Zealand into a big polygon. However using the vector -> geometry tools -> lines to polygon command in Quantum GIS results in a ...
6
votes
2answers
870 views

Need to merge overlapping line segments

I'm working with fish distribution data, and have combined several 24k habitat maps into a single layer that I'll call "critical habitat" In merging multiple distributions into one dataset, there are ...
6
votes
1answer
2k views

How does Flow Mapper Plugin work?

I downloaded the Flowmapper plugin for Qgis and I can't seem to find any information on how it is supposed to work... Also the text seems to cut-off and not fully showing for the input fields so I'm ...
6
votes
1answer
9k views

Calculating line segment lengths within polygon using ArcGIS Desktop?

I have a layer with line segments and a layer of polygons (in this case, buffers around points). I need to create a new field for each polygon that contains the total length of all line segments ...
6
votes
1answer
3k views

How can I add an arrow to a line?

I want to have arrow heads at the end of a number of lines. I add these through Line properties --> Line decorations. It looks nice and all when displayed in the legend: But in my map, due to ...
6
votes
1answer
811 views

How to connect places (points) without crossing lines?

I have two sets of data. One with placemarks represented by blue dots in image below, and another set of geographic data with lines represented by grey lines. 1) For the first point in drawing, I'm ...
5
votes
1answer
237 views

How do I make line symbols intersect cleanly without showing edges in QGIS?

I digitised a map showing electric grid lines. I merged a number of lines into a single feature. Now, I'd like these lines to be displayed so that the intersections appear continuous. At the moment, ...
5
votes
4answers
3k views

Breaking a dynamic text line in data driven pages

I am using data driven pages and some of my dynamic text attributes are too long for my layout. Is there a way to break the line into 2 or more lines with out editing the data? Example: FROM Billy ...
5
votes
1answer
255 views

Given 2 LINESTRINGs with common point, how to extract common point?

I have 2 LINESTRING geometries. I know both share a common point. Using PostGIS for Postgres, what is the cleanest way to extract the common point? Example with illustration: How do I extract the ...
5
votes
2answers
389 views

Grouping lines together to form one line after a distance threshold is met: ArcGIS 10

I have lines on a map showing the most direct way from point data to the coastline (polygon). I would like to group the lines if they are close to each other by a distance that I can set. Where the ...
5
votes
2answers
75 views

Placing random line segments within polygon?

I would like to generate multiple line segments of a fixed length, a random bearing, and both segment endpoints within the polygon. It's not clear from the example, but it's fine if the segments ...
5
votes
1answer
297 views

How do I create a SpatialLinesDataFrame from a dataframe?

I have created a data.frame in R . I want to get SpatialLinesDataFrame as a result so I understand that I have to convert the data.frame into lines, the lines into SpatialLines and the SpatialLines ...
5
votes
1answer
700 views

How to split a line into a specific number of parts?

I've seen a lot of questions involving splitting a line with the help of a point layer. I want to split a line in fractions of its length. For example, I have a line 400 meters long, I want to split ...
5
votes
2answers
319 views

Can someone clarify some details about freehand line tracing in QGIS?

I have read several tutorials and questions here on this site, but I have some lingering questions/doubts that I would like clarified. My project is tracing roadways from a 1926 map so that I can ...
5
votes
1answer
107 views

How to get smallest line segments from intersection + difference of multiple overlapping lines?

Inspired by this question, and this excellent answer. I have multiple overlapping lines and want to extract the complete intersection of them. So from this sample data SELECT id, geom INTO stackex ...
5
votes
1answer
536 views

How to connect particular sets of points with (poly)lines?

I think my problem is quite easy to be solved by the most postgis-users, but i am a bloody beginner: i have a timestamped point-table representing GPS-tracked places of different cars. To distinguish ...
5
votes
1answer
961 views

Is there a way to split polygons by several lines in QGIS?

I have a polygon (.shp) and a line (.shp) layer. I want to split the polygon in several pieces along the lines that overlap the polygon. Afterwards I want to edit each polygon separately (attribute ...
5
votes
2answers
351 views

How to calculate the area between two line shapes?

I'm a newbie using QGIS (2.0). I'm trying to calculate the sidewalk area of a city. For that I have some shapes, extracted from Mricostation, with the topology (facades, fords, fences, etc.), but ...
5
votes
1answer
567 views

How change border line to no pen with python console?

From Python console I load a shapefile with qgis.utils.iface.addVectorLayer. How I can remove border lines (change to no pen) in the active layer?
5
votes
0answers
173 views

Search Radius for Line Density [closed]

I have been working with GIS for many years but I am fairly new to the spatial analyst side of things. I am working with many satellite tracks for many different individual animals and would like to ...
5
votes
0answers
138 views

Why doesn't Polygonizer copy the line ids to my polygonized shapefile?

I am trying to convert a line shapefile into a polygon shapefile using Polygonizer plugin, and when my new polygons are created all the cells in my id field are "Null", although I have clicked "copy ...
4
votes
3answers
2k views

Efficient algorithms to split and join lines?

Referring to the Figure below: How to efficiently join segments into lines? How to efficiently break lines into segments? The above will be applied million times.
4
votes
2answers
4k views

Compute Angle of line in conventional bearing using ArcGIS API for JavaScript?

I am trying to compute angle between two lines (line segment) using ESRI (ArcGIS, JS) in conventional bearing (Eg: N29'E) I am using Add Toolbar to draw a line segment where point A is a fixed point ...
4
votes
1answer
176 views

How best to map lines based on multiple attributes?

I need to plot lines onto a map to display road quality. I'm already using colours to distinguish between different road conditions, but I also need to display another factor - the survey origin. ...
4
votes
2answers
3k views

Workflow for creating line features between two coordinate pairs in QGIS

I have a table of stream reaches with xy coordinates for their respective tops and bottoms. I'd like to convert the table to a feature, using the xy coordinates as the endpoints of the line. Any ...
4
votes
1answer
43 views

cartographic line develop spikes when applied offset value

version: ArcGIS 10 I am using a number of lines in certain polygon. As I apply offset value to the outline, spikes/kinks are produced as shown in the picture. Any solutions to remove the spikes and ...
4
votes
1answer
321 views

Horizontal only line thickness in ArcGIS

Is there a way so line thickness only expands horizontally from the centreline? I am making a road condition map and found it may not be truly representable. The red on the left overlaps the yellow ...
4
votes
1answer
576 views

Clipping Line shapefiles within extent of Polygon shape?

My question is an extension of Vertical lines in a polygon shapefile. Kindly refer to that question first. What you shall see there is a method of generating vertical lines with respect to the ...
4
votes
2answers
81 views

extending existing line in QGIS by adding nodes

I am trying to extend an existing line by adding nodes to it. Is this possible to do in QGIS without creating a whole new line?