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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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 ...
3
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3answers
2k 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
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3answers
571 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 ...
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1answer
3k 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
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1answer
84 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 ...
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1answer
230 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 ...
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1answer
123 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 ...
4
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1answer
1k 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 ...
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1answer
759 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 ...
3
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1answer
835 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 ...
7
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2answers
2k 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
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2answers
308 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 ...
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1answer
676 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 ...
5
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1answer
2k 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?
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1answer
110 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?
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1answer
522 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. ...
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1answer
626 views

Converting LinestringM to Polygon PostGIS

I'm working with PostGIS and plotting polygons on a Google Earth plugin. I've found a few examples via Google on how to convert a LinestringM to a Polygon for rendering, but none of them, including ...
7
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2answers
1k views

For a given feature find the closest point along a given path

Looking for a Java based (foss4g) solution for the following: I am using a path along with a buffer to find features that are along the path. For each of the features returned I want to find the ...