A sequence of point coordinates referring to the line segments connecting them, as used to represent a one-dimensional feature or object.

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109 views

Check if point is near a linestring Spatialite

I have a LINESTRING made of two points start point and end point in spatialite. UPDATE points SET road_geometry = GeomFromText('LINESTRING(24.889142 67.196188, 24.889673 67.196579)',4326) where ...
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2answers
3k views

How to find nearest line from point using PostGIS?

I have a table of Roads in PostGIS which geometry is "geometry(MultiLineString,4326)". Its attribute are gid osm_id name ref type oneway bridge maxspeed geom Now i want to know ...
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1answer
57 views

Closed Linestring

I've created a linestring using st_makeline(). When I draw this linestring using QGIS it always makes it closed. The start and end points are not the same and I verified by using st_startpoint() and ...
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0answers
88 views

Postgis - Split linestring between point A and B

I need to find the different trajectories between point A and B. In the image is possible to see 2 differents trajectories. The way i use to calculate them is: Found the min time and the max time (in ...
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1answer
38 views

Linestring to CartoDB api

I want to add a linestring to a CartoDB API web app for one time use, I have SQL statement being ran at the same time and just want the linestring in the SQL statement to be displayed.
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1answer
199 views

Showing Linestring from SQL statement with CartoDB

I have cartodb sql statement to return what polygons are intersected by a linestring, but I'd like to have the linestring visualized over the polygons on the results. Also not add the linestring to ...
3
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1answer
89 views

How to find intersected line is from left or right on another line?

There is a main LineString and its direction is known. I want to find the side of intersected lines to this main line. Example image: Black line is main LineString and red one is intersected ...
3
votes
2answers
566 views

In PostGIS, how do I merge a multilinestring into a single linestring, keeping the pieces in proper order?

I have a multilinestring made up of several pieces, some of which are facing the wrong direction. (Accessible here: http://pastebin.com/89Zcixv5 ) I think what I'm looking for is some utilization of ...
6
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2answers
604 views

Split lines at intersection points

I've got some linestrings covering a road network, and need to split them at the crossroads. Does anybody have any idea on how to do it? I'm using QGIS 2.4, with a Postgis 2.1.3.
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1answer
101 views

Bounding box of a set of MULTILINESTRINGs PostGIS

I have a PostGIS table with a geometry column (geom) and a type column. The geom column contains only MULTILINESTRINGs and the type column contains tags that tell me what each MULTILINESTRING ...
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1answer
96 views

How to get the LineStrings from a MultiLineString

I was wondering if there is a way I can extract the LineStrings from a MultiLinestring object. What I am really trying to do is look into a MultiLineString and see if I have a certain LineString. I ...
3
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1answer
189 views

PostGIS: Get closest point between geometry and Multipoint

I think my question is not that difficult for GIS professionals, but i didn't found an answer to my problem (even not in other questions). Problem: I have given two tables (table1,table2) with Points ...
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2answers
117 views

Densify a JTS LINESTRING (add points)

I have a LineString I would like to "soften" in a way that if two coordinates (vertices) in the LineString are very far apart, I want to automatically add some coordinates in between. The line ...
3
votes
1answer
351 views

OpenLayers: How to get *real* centroid of a Line Geometry/Feature?

I have declared a line geometry as: var lineString = new OpenLayers.Geometry.LineString([source,target]); then I am trying to get the centroid of this lineString as lineString.getCentroid(). But ...
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0answers
190 views

OpenLayers - Add points at vertices of line while drawing line

I would like to create points while I draw a line on my map in OpenLayers. That is, at each vertices of a line and at the end points there is a shape like a square, circle, or diamond. I have this ...
3
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1answer
325 views

Find the closest line vertex from the linestring using PostGIS

How to find the closest line vertex from a linestring? ST_ClosestPoint will give a point which is not from the linestring.
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1answer
66 views

ValueError when instantiating LineString from a mix of tuples and Point objects

I'm new to Shapely, and tried instantiating a LineString object from a mix of tuples and Point objects like this: >>> LineString([Point(1,2),(2,3),Point(3,4),(5,5)]) I get the following ...
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1answer
251 views

Distance Between Two Points vs Length of Linestring

So I have two points that I want to calculate the distance between. If I use: SELECT ST_Distance_Spheroid(point_a, point_b, 'SPHEROID["GRS 1980",6378137,298.257222101]') / 1000 FROM ( ...
2
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1answer
370 views

Merge multiple linestring features into a single multilinestring

Using QGis or ogr2ogr how do I convert a vector file containing multiple linestrings features into a single multilinestring feature? At the moment I've been doing this manually by converting the data ...
3
votes
1answer
222 views

Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
2
votes
1answer
329 views

How to extend a straight line in postgis?

I have a postgis table of simple linestrings, each one is a straight line with just two points. I want to select every linestring, but extended from both sides by 1 meter. So i have lines, that are ...
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1answer
30 views

Geometry conversion problem.Data loss

I was trying to convert a roadnetwork table.Its geometry contains both MULTILINESTRING and LINESTRING.I converted all the MULTILINE string to Linestring using the query update all_india_merge set ...
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0answers
224 views

PostGIS: How to distinguish overlapping routes (i.e., LineStrings) based on their direction?

I have a set of routes which are represented by LineStrings in my PostGIS database. These routes represent journeys that people make. I want to come up with routes that (a) overlap, and (b) have the ...
2
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2answers
210 views

OSM linestring shown as point

I have loaded the following file http://openstreetmapdata.com/data/coastlines to postgreSQL. In visual studio with gdal/ogr and geos enabled: SELECT geom FROM waterpoly WHERE geom IS NOT NULL LIMIT ...
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2answers
868 views

How to group connected linestrings in PostGIS?

I have a table of streets I've selected based on a set of attributes (let's say it's speed_limit < 25). There are groups of streets that are locally contiguous; I'd like to group these sets of ...
5
votes
1answer
216 views

How to transform a set of street-segments into city-blocks, with PostGIS2?

Theoretically is possible to obtain the polygons of city blocks (urban blocks) from streets, when streets are represented by street axis (LineStrings). The urban blocks are bounded by streets, so ...
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1answer
219 views

How to cluster similar lines in PostGIS?

In PostGIS I have a large database of linestrings which I have obtained using ST_makeline function. I would like to cluster similar lines based on where the lines start and end. Here is an example ...
4
votes
1answer
435 views

Calculating “travelled distance” of a GPS track without including “stops”

I have a set of GPS tracks from a cycling event and I want to correlate their distance along the route. Problem is: when a rider stops, generally by entering a covered place, GPS keeps logging (low ...
4
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2answers
290 views

How to speed up a query for nearest linestring to point data

I have processed a Strahler stream order layer with a lot of river linestrings (type: Multilinestring) and their corresponding strahler number (see information here). Besides I have a point layer. I ...
2
votes
2answers
280 views

Switch coordinates in linestring

I made a silly mistake: when creating linestrings in my PostGis database i inverted the lon and lat values. Which isn't a problem for postgis itself, but for my visualization and intersections. ;) Of ...
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1answer
35 views

violates check constraint

I try to add a constraint based on geometry type to a "street" table that prevents anything except Linestring geometry or Null. alter table streets add constraint streets_geom_linestring_chk ...
4
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0answers
145 views

How do I simplify the straight sections of (multi)Linestring in PostGres/PostGis leaving the curved sections untouched

I have (multi)linestrings containing upwards of 5000 points and I want to perform two simplifications possibly using Ramer Douglas Peucker or alternative methods in PostGis The (multi)linestrings ...
0
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1answer
111 views

Why are some OSM GPX line string endpoints connected?

I am working with GPX files from OpenStreetMap to render the public transportation lines of Berlin. I converted them to GeoJSON using the togeojson script. For some reason some of the lines are ...
2
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0answers
316 views

How to add an offset to a GeoJSON layer in Leaflet?

Using the example GeoJSON tutorial code at leafletjs.com. Change the myLines variable so that the two lines overlap, but run in opposite directions as follows: var myLines = [{ "type": ...
2
votes
1answer
414 views

How to use makeline() function for more than 2 points in spatialite?

Is it possible to use makeline() function to make linestring geometries in spatialite for connecting more than 2 sequence points? Suppose I have four sequence points P1, P2, P3, P4. Or are there any ...
0
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1answer
96 views

Can I use Point as the geom type in pgrouting?

in my table i have the field geom(POINT, srid) and its populated, this table also have the source an target field witch is blank(just like pgrouting guide). I tried the function pgr_createTopology() ...
3
votes
1answer
232 views

Select linestrings containing points with duplicating M coordinates in postgis

I have a table of LineStringM geometries. Some of lines have points with same measure (M coordinate). This is a bug in initial data, that I want to clean somehow. So I need to: 1. Select all records, ...
0
votes
1answer
90 views

Simplify table of linestrings

I have a PostGIS table of linestrings representing a road network. I want to simplify the geometries such that only lines that connect road junctions are stored. At the moment the table has a large ...
4
votes
2answers
1k views

How to perform SIA or Bezier line smoothing in PostGIS?

Can anyone provide an example SQL for smoothing linestrings from postgis table using Bezier curves or Iterative Averaging (SIA) algorithm?
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1answer
68 views

Line style width property not being applied in QGIS 2.0.1

I change the line width of my style and click apply, but the property does not seem to be applying to my line data.
1
vote
1answer
127 views

Separating distinct lines in PostGIS

I have a table of linestring segments in Postgis. These segments make up distinct non-intersecting lines as shown by the diagram. To add confusion the direction of the linestrings are not uniform. I ...
0
votes
1answer
296 views

Linked point geometries to linestrings in Spatialite

I have been parsing Canada's radio system frequency open data. It's a single large table per province, containing point geometries for each station callsign. Where a point-to-point link is defined, ...
2
votes
1answer
927 views

PostGIS: Calculate the length of just the portion of linestring that intersect with a polygon

I want to calculate the portion of the linestring that lies within the limits of a polygon. Better with an image What is the length of the portion of linestring within Province A? and within ...
0
votes
1answer
306 views

Defining a WHERE clause from a subquery for a query to create a handy view

It is about my implementation from an answer of this question. It is more an postgresql issue than a GIS issue, whereas it is about geometries and spatial queries. I want to create a view from the ...
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vote
1answer
83 views

PostGIS | Get degrees clockwise from north of a linestring's beginning and end

I have a table full of linestrings in PostGIS. I would like to know the degrees clockwise from north of the starting point of the linestring and also of the end point. I was thinking that maybe ...
4
votes
2answers
497 views

How to calculate the azimuth of a line of a multilinestring in PostGIS?

I have two spatially enabled tables in PostgreSQL with a geometry in each: First table is with POINT type, second is with MULTILINESTRING. I need to calculate the azimuth of the LINESTRING part of a ...
7
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4answers
622 views

How to calculate the “depth” of a linestring using postgis

I have linestring features, which look like bent linestrings, hemicycles or convex or concave linestrings. In the moment I can select the distance between the startpoint and endpoint of each feature. ...
3
votes
1answer
360 views

PostGIS: Using a polygon to 'mask' linestrings returns both multi and linestrings

I have a table of linestrings (OSM roads, in fact) that I'm displaying on a map. I want to filter them so that only those within a certain area are displayed- I've already done this with the coastline ...
4
votes
1answer
806 views

How to create linestrings with a definite angle and length, that are fixed to a point

I want to create linestrings with a definite angle (e.g. 160°) and length (e.g. 2m) that are fixed to a number of points of another linestring. So, I want to use the ST_DumpPoints function to find the ...
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vote
2answers
590 views

Extract a LineString from LineString by two Points

I am using PostGIS2.0 and PostgreSQL9.3. I have LineString in Spatial-Ref 4326 like geom:= ST_GEOMETRYFROMTEXT('LINESTRING(60.7014631515719 56.8441322356241,60.7023117507097 ...