A sequence of point coordinates referring to the line segments connecting them, as used to represent a one-dimensional feature or object.
0
votes
0answers
35 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 ...
0
votes
2answers
96 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 ...
0
votes
0answers
28 views
Join Geological Linework based on shared attributes while obeying rules
I'd like to join all adjacent geology faults within a table if they share the same attributes in f_type, f_class, f_name and f_conf columns. However I don't want to join adjacent lines with equal ...
1
vote
1answer
66 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, ...
1
vote
0answers
76 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 ...
0
votes
0answers
32 views
How to add vertices to existing linestrings in mysql?
Is it possible to add a Point at the end of a Linestring in MySql?
For example I have a Linestring as
Linestring(1 2, 1 4, 1 6)
and I want to add a Point
Point(1 7)
at the end (output should ...
0
votes
1answer
81 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 ...
1
vote
1answer
64 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?
1
vote
1answer
52 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 ...
6
votes
4answers
227 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
0answers
68 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
...
1
vote
0answers
109 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 ...
1
vote
0answers
87 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 ...
1
vote
1answer
52 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 ...
2
votes
0answers
30 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
136 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 ...
1
vote
1answer
96 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
votes
1answer
97 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 = ...
2
votes
1answer
76 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 ...
3
votes
0answers
124 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
117 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 ...
5
votes
1answer
120 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. ...
1
vote
0answers
183 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
325 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 ...
1
vote
1answer
204 views
How to find the nearest line from a point?
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 ...
3
votes
3answers
250 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 ...
2
votes
2answers
335 views
Create point to a 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?
Cheers, Sanna
4
votes
1answer
199 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 ...
6
votes
2answers
178 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)
3
votes
1answer
135 views
Polyline “breakage” calculation in MapInfo?
I am a novice MapInfo user, with a basic to moderate knowledge of queries and SQL. My work entails doing risk assessments for shipping traffic based on AIS-tracks (radio-based vessel information ...
3
votes
0answers
330 views
leaflet - Drawing line following the road
Short version:
What I wish to be able to do is drawing a polyline along part of a road. In that way marking certain houses, along this road.
Long Version:
I have several houses that I wish to mark ...
6
votes
1answer
106 views
How to see what lines have changed in an updated Shapefile?
I'm using my county's GIS data to update the roads in OpenStreetMap. I have a copy they published last year and one that was just published, and I'd like to find all the LineStrings that have either ...
0
votes
1answer
120 views
What is the fastest way to identify the two nearest linestrings using PostGIS?
I want to be able to identify the closest roads to two points that are generated through geocoding (a start and end address). The points will likely be near a linestring. Two approaches that I have ...
1
vote
2answers
391 views
How to offset point perpendicular to line direction in PostGIS
I have a postgis table of points, that are sitting on road centerlines (I've linear referenced them). And the second table with road centerlines themselves.
The point table also has a field roadid and ...
2
votes
3answers
739 views
How to delete duplicate lines?
I was wondering if anyone could help. I have a tab file in MapInfo consisting of just polylines. Each is meant to have its own reference number, however some are duplicated (e.g two lines occupying ...
6
votes
3answers
312 views
How to generate geodesic linestring from two points in C#
I'm looking for a FREE C# class, library or set of functions that will allow me to generate a geodesic linestring (or array of vertices, whatever) from two decimal degree points.
I've found ...
1
vote
1answer
1k views
show a Collection of LineStrings with labels
I use the following peace of code to show multiple LineStrings which have a point as the last one, along with a label:
var strokeColors = [...];//"#FFAACC" kind-of elements
var linesLayer = new ...
4
votes
1answer
71 views
Rasterise heights from a 3D linestring
I have a 3D network of streams represented using linestrings with Z-coordinates. I would like to rasterise this feature, where the raster values represent the linearly interpolated Z-values between 3D ...
1
vote
1answer
160 views
Using Python in Arcmap to partition strings [closed]
I have a title "Text that remains Proposed Thing to replace"
var_a = New Text
I want the output to be
"Text that remains Proposed New text"
Currently outputs this
"(u'Text that ...
4
votes
1answer
555 views
PostGIS geometry intersection test results different for Point and Linestring
Can anyone please tell me what I'm doing wrong, and how do I avoid the problem? I'll attempt to clarify what I'm doing as things go along.
The geom column is a multipolygon column, all values are ...
0
votes
1answer
95 views
Postgis reorder mixed up linestring chunks / max_segment_length(linestring)?
I imported ~1000 paths from somewhere into my postgis database to a linestring field.
I had the problem that the paths were divided into chunks, and those chunks were mixed up in some cases.
Suppose ...
2
votes
1answer
424 views
How to detect overlapping linestrings in PostGIS?
I'm looking for the fastest way to detect whether a given linestring overlaps another linestring. (As reference, let's say my wife and I both go for a run and take different routes, I'd like to detect ...
2
votes
1answer
342 views
How to create a efficent linestring out of geography points using postgis
I'm trying to create a linestring out of geography points. At the moment I'm doing it like this:
select ST_GeographyFromText(ST_Makeline(a.record_point)) from (
select (record_point::geometry)
from ...
3
votes
1answer
356 views
clip linestring by length
Is there a way to clip a linestring based on distance?
For example, linestring from a to b is 150 meters. I would like to get the linestring from a to a point that is is 75 meters away from a ...
5
votes
1answer
455 views
How to merge linestrings that don't touch based on common name?
I had a table of road line strings that contained duplicate road names with different geoms for different line segments. I extracted the duplicates to another table. I now want to join these segments ...
3
votes
2answers
230 views
How to recalculate the the length of a geography linestring from nearby geography point in POSTGIS?
I have a geography type linestring
*route_geography geography(LineString,4326)*, its a route from point A to point B. Now I have a point C near that line. I want to find the nearest point on that ...
6
votes
2answers
1k views
How can I export a linestring to a GPX file in QGIS?
I have a linestring in a vector layer in QGIS. How can I expot/save this linestring as a GPX file?
I tried to select the linestring, then right click on the vector layer and choose "Save selection ...
3
votes
1answer
738 views
How can I transform a polygon to a 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?
2
votes
1answer
94 views
Access points with PostGIS
I have a PostGIS table with linestring geometries and point (A) on it and I need to detrimine points (M) which located M meters from A. Distance is measured along linestrings. Any thoughts?
1
vote
1answer
367 views
Create shape file of bookmark extents and/or automatically print bookmark extents to pdf
Is it possible to export the extents of all bookmarks in an active map document to a shape file containing the polygons of the shape and/or to automate the print to pdf of all the bookmark extents.
...
