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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111 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() ...
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3answers
1k views

Cannot st_linemerge a multilinestring because its not properly ordered

i have a MultiLineString which i created by using st_union in many steps. Each of them are connected to each other according to their points, but the order is not correct. So ST_LineMerge is not able ...
0
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1answer
98 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 ...
5
votes
1answer
286 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
143 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 ...
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3answers
537 views

Create multi-line from point in PostGIS

I'm working on an old table where polygons are stored as points. Now, I want to migrate these points to PostGIS and store them as polygons (or multi-polygons). The table structure is as follows: ...
3
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1answer
1k 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 ...
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1answer
479 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 ...
1
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1answer
101 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
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2answers
772 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 ...
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1answer
79 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.
4
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1answer
1k 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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2answers
901 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 56.8445673405349,60....
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2answers
377 views

Mapserver - label at beginning of line string (WMS)

I am creating a WMS service made up of linestrings pulled from a POSTGIS database I want to label the start of each line with a sequence number. At present I can label the centre of each with:- ...
2
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3answers
373 views

postgis linestring segmentation in 4326

How can I divide a single postgis linestring with SRID 4326 into segments (preferably an array of linestrings) with no segment longer than a given distance? I've tried st_segmentize(), but it spits ...
3
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1answer
305 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, ...
2
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2answers
253 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
1k views

How to create a MultiLineString feature with a postgis layer in QGIS

I have troubles handling with MultiLineStrings in QGIS. I added the table where I defined a column as geometry(MultiLineString, 31468) as a postgis layer in QGIS. Now I want to create features with ...
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2answers
227 views

Frequency of partially or fully overlapping lines

Let L be a set of line-segments (lines) in a two-dimensional (2D) Euclidean space that are randomly (say, using uniform random function) distributed, that is, some may overlap other(s). Overlapping ...
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1answer
348 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
2k views

How to find the intersection point of polygon geometry and multilinestring geometry in postgis

I have a polygon geometry and multilinestring geometry. How do i find the intersection of both these geometries. Both the geometries are in same reference system. Does st_intersection gives me the ...
3
votes
1answer
1k views

how to split a line by a point which is on the line but not in the linestring itself?

i need some help with the following: i have a linestring - geom i have $lat,$lon (using some php syntax) i have an osm table with the roads geom, i am trying to get closest point, and then split ...
4
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2answers
933 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 ...
0
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0answers
183 views

Diferent Line color and Diferent Markers at the same time

i'm about to develop a GIS Track App, but until now, i'm testing with some codes, that i've been creating, but for my project we are going to use XML as data records, today, i am able to create a ...
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2answers
629 views

How to split a linestring every 1000 points in postgis

To assume compatibility with my survey software, I would like to lighten geometries of my linestrings by cutting them every 1000 points without creating or interpolating points. I transformed a ...
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1answer
1k views

From a trajectory of GPS points to a 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, ...
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0answers
651 views

Line to Polygon via Polygonizer in QGIS

My question is in the same vein as this one. I'm attempting to convert precipitation lines (Precipitación Media Anual) to a polygon for Mexico in QGIS using the Polygonizer plugin. After running the ...
1
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1answer
288 views

Openlayers Linestring over edge of map

im trying to create a route displayer for ships. But im struggling with the edges of the map. When going from ie. 179* to 2* it displays a line across the entire map, instead of displaying it on the ...
5
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?
2
votes
1answer
624 views

How to Blink a line on a map similarly like a point blinking on map through lat lon points

how to blink a line on a map which is formed by lat lon points through linestring from database the points(lat,lon) comes which is stored in form of MultiLineString. similarly like how a point ...
7
votes
4answers
723 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. ...
4
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0answers
275 views

PostGIS 2.0 st_geomfromgml using LineString fails with invalid GML representation

I am attempting to insert a geometry into a table using the st_geomfromgml function. The GML is being sourced from a Geoserver WFS request. The function call looks like this st_geomfromgml('<?...
2
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0answers
761 views

How to merge linestrings which are connected with each other?

I would like to join linestrings which are connected to each other. The preferred output is a longer linestring based on all joined single linestings! The table that holds my single linestrings is ...
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0answers
241 views

Break LINESTRING values in postgis into mutiple LINESTRINGs

Figure A below is the visual representation of what i have in my road data set. Line 1, Line 2, Line 3 in illustration are each represented as 1 row postgis DB inside a geometry column, some of these ...
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1answer
97 views

How to get routes in the database that intersects circle?

I have routes (linestrings) recorded in the database. I want to create a query which returns the routes that have some commonality with a circle whose center and radius are passed as parameter. I ...
3
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2answers
154 views

Find gap in / endpoints of linestring

I have a set of features of type linestring. I'm trying to polygonise the linestrings and assumed that they were closed (naive me :) ). Of course some were not closed and I'm trying to locate the gaps ...
3
votes
1answer
425 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 ...
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1answer
508 views

Why ignores Google Earth the gx:altitudeOffset in KML files?

I am currently writing software that creates 3D polylines and outputs these in KML format. According to the official documentation it is possible to define an altitude offset via gx:altitudeOffset to ...
0
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1answer
982 views

how to find vertices for a geometry in OpenLayers

I am having a LineString, where I need to find the vertices logically and save those vertices. Can anyone help me out. Or else how below can help me. OpenLayers.Geometry.LineString = OpenLayers....
2
votes
1answer
106 views

What is the PostGIS function for retrieving buildings by road side?

I want to get information of buildings by the road side only. Assuming that the building table has multi-polygon geometry and the road table has multi-linestring geometry, what would be a pgSQL Query ...
5
votes
0answers
775 views

ArcGIS Kernel Density with polyline, search radius / bandwidth calculation

I'm conducting a density analysis of a series of polylines and I'm hung up on determining an appropriate search radius. The default calculation performed by arcgis is to take the shorter dimension ...
8
votes
1answer
511 views

How to rank polylines according to their similarity to a ref polyline?

How to rank polylines according to their similarity to a ref polyline? Update 1: simulations show that simple $\sqrt{\sum{(case-ref)^2}}$ can find better similarity between polylines (as set of ...
6
votes
1answer
654 views

How do you fix Overlapping Lines?

I have a line dataset that contains some lines where the "end points" are actually found in the middle of the line. In the image below, the nodes are shown in green and one of the end points in red. ...
2
votes
0answers
1k views

How to handle postgresql/postgis geometry type errors in a function?

I have created the following function in PL/SQL to make a polygon from a set of linestrings: CREATE OR REPLACE FUNCTION _myfunction( _fid integer, _rid integer ) RETURNS VOID AS $$ ...
4
votes
1answer
2k views

How to create polyline of varying distance from origin point using azimuth?

I am looking for a Python script that does the following: Uses a point (from a point shapefile) as the origin. Creates about 3 km line from point Based on an azimuth provided in the original point ...
3
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2answers
4k 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 ...
7
votes
4answers
5k views

How to extract POINT from a [LINE|MULTILINE]STRING

I'd like to create a vectorLayer in QGIS to display all the points that form a LINESTRING or a MULTILINESTRING stored in a PostGIS DB. I think that I need to transform all points of LINESTRING (or ...
3
votes
3answers
3k views

Creating point to center of polyline?

I'm trying to create a points in the middle of polylines. The data is now in the form of shapefile. Is there an easy way to do this?
5
votes
1answer
656 views

adding multiple points to a linestring in PostGIS

Though a newbie to PostGIS, I'm having trouble solving something that I think should be farily straightforward. I have two linestring tables, both consisting of simple, 2-node line objects: one has ...
8
votes
2answers
1k views

How to add vertices to existing linestrings?

If I have Linestring(1 2, 1 5, 1 9) and a Point(1 3) Is there any function that can merge linestring and point preserving the order so output would be: Linestring(1 2, 1 3, 1 5, 1 9)