Questions tagged [geometry-conversion]

A change from a geometry type to another, e.g., points to lines, lines to polygons, polygons to points, and the like.

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27
votes
2answers
33k views

Converting point sets to polygon boundaries?

I'm trying to convert sets of points to their respective polygon boundaries. I think this is something like a Voronoi diagram or Convex Hull, but not quite. I'm sure there's a technical term for it, ...
17
votes
4answers
21k views

Converting Polygon into single or all Points using QGIS?

I want to convert polygons into points using QGIS. I know how it's done in ArcGIS Desktop.
13
votes
1answer
18k views

Transforming polygon to 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?
19
votes
2answers
44k views

Create polygon layer from polyline layer

Our systems expect polygon shapefiles, representing a collection of non-intersecting and geometrically valid (multi)polygons. Specifically, farm fields. We often receive our representations of farms ...
10
votes
4answers
15k views

Get all the points of a polyline

I have some polyline feature objects in python. Now I want to get all the points of polylines. For example, if a polyline has start point [0,0] end point [5,5]. Result: [1,1];[2,2];[3,3];[4,4];[5,5]...
28
votes
2answers
51k views

Draw lines from points in 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 ditance between the point and the line). The nodes of the line will recieve the attributes of ...
12
votes
5answers
62k views

Creating polygons from lines using ArcEditor/Standard level license of ArcGIS Desktop?

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 ...
10
votes
4answers
4k views

Generate polygons from a set of intersecting lines

This is a simple and quite common question which has already been asked for different purposes (see this link and this too, for example), here, however, we are looking for not a software package but ...
2
votes
1answer
926 views

Changing geometry types from kml points Z to just points in QGIS

How do I change geometry types from pointZ to point in QGIS from a kmz file?
3
votes
1answer
2k views

Split polygon into lines

I have a polygon layer which looks like this . I used the QGIS multiparts to singleparts tool and also polygon to lines. In both cases i got this type of result . I want to extract polygon into ...
6
votes
2answers
5k views

Create Polylines from arrays of points

Let me describe the data setup. A line has been provided as an array of coordinate pairs, one for each vertex. This array is variable in size, anywhere from 2 to 200 coordinate pairs per line. What I ...
3
votes
1answer
7k views

Creating polygons from points in Mapinfo

I have a huge number of points(co-ordinates), from which I am required to draw a polygon in Mapinfo. This required polygon is a square of 200m size. All I have now is the left side lower end of the ...
11
votes
6answers
7k views

Lines to Polygons

I have failed to find the "name" of the algorithm that would allow one to convert lines to polygons. Since this issues crosses GIS and the fields of computational geometry and computer science. I am ...
3
votes
2answers
321 views

QGIS split rectangular polygon in grid

I have this selected rectangular polygon in yellow on a layer with hundreds of polygons: I need to split the selected polygon in 4 vertical columns (Y axis) and 8 horizontal rows (X axis), so that I ...
3
votes
3answers
2k views

How to convert points to lines?

I want to convert these points to lines, however they are not sorted sequentially along a line (by ID or FID), i.e. the converted lines zig-zag across the obvious trail of points. How can I join ...
9
votes
1answer
5k views

Creating line from points using PostGIS?

I have a PostGIS table with position data of numerous vehicles and want to create lines from these points. Data can be selected by vehicle id and ordered by timestamp but how to create lines from ...
5
votes
3answers
4k views

Converting SpatialLinesDataFrame to SpatialPointsDataFrame in R?

In R I have a SpatialLinesDataFrame (for example from a coastline shapefile) and I want to convert it to a SpatialPointsDataFrame. I want to keep all the vertices from the line shapefile to become ...
3
votes
1answer
6k views

convert list of points to line or polygon

I have a list of Points in a PostGIS table. The rows can be grouped by a date something like: myTable id INT date DATE lat NUMBER lng NUMBER geom GEOMETRY(POINT) now I need a table where all ...
7
votes
1answer
993 views

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

I have a timestamped point-table representing GPS-tracked places of different cars. To distinguish the cars there is a car-id for every point. So, a simplified version is looking like that: Now, I ...
5
votes
1answer
1k views

Convert linear polygons to lines

I have some long linear polygons that I'd rather store as lines but I'm not sure how best to do this. Ideally I'd have a line going through the centre of the polygon lengthways. I have two ideas of ...
5
votes
2answers
3k views

Convert shapefile lines to a polygon in GRASS

I have a shapefile of a map that is the outline of a number of islands. I would like to convert the lines into polygons (ie all islands filled in) using GRASS. I searched on how to do this with GRASS ...
5
votes
2answers
8k views

How to convert a line to points?

I'm working with QGIS and I want to convert a line into many points, does someone know how?
4
votes
2answers
2k views

How to join lines in QGIS for later using “lines to poly”?

After successfully merging lines (using snapping) with merge_selected_features i got nice result - one merged line. Next thing was to make polygon from created merged line. Result is not nice - it ...
4
votes
1answer
1k views

Generating polygons with streets as borders using QGIS?

I have searched online for almost a week and can not find an answer to my issue. I need to generate polygons from street borders in a given city. I have downloaded data from openstreetmaps and ...
3
votes
2answers
5k views

Conversion between lat/lon and local coordinate system

I have local coordinate system, this is the red grid on the image. Red grid XY points measured in meters, and I know: The 0;0 point of the red grid and the lat/lon coordinates of this one point. (the ...
3
votes
2answers
3k views

Merge single points to multi point geometry

Is it possible to transform a point shapefile in single part geometry to a shapefile with multi-point geometry based on an attribute. e.g. in the file are 50.000 records in 700 categories, now I want ...
2
votes
0answers
383 views

converting shp to fileGDB with ogr2ogr changes geometry type?

I'm converting a shapefile to file geodatabase with GDAL 1.11.3 and the ESRI FileGDB driver. ogrinfo on the .shp gives: $ ogrinfo NED1_Index.shp INFO: Open of `NED1_Index.shp' using driver `ESRI ...
2
votes
1answer
3k views

how to connect points to create a polygon boundary in QGIS

I have 31 points in a shapefile, which delimit a field (it's an irregular shape). I want to connect those points so they create the boundary of a polygon. Does anybody know a kind of "connect the dots"...
2
votes
1answer
6k views

How to connect points to line in Mapinfo?

I am using Mapinfo and Mapbasic. I have all the points stored in a DBMS. I have four columns with four points longitude and latitude. Is there any way to connect the points? I am using Mapinfo 10....
2
votes
2answers
581 views

Convert point file to polyline but not joining every set of points in ArcGIS10

I have a dataset that looks like : OBJECTID Shape KP DESCRIPTION EASTING NORTHING 1 Point 0.04 Span;Start 525112.2 6728715.4 2 Point 0.0506 Span;End ...
2
votes
1answer
1k views

How to convert points into line without changing the attributes? [closed]

I have several points and its attributes. I want to classify them into some class, but I want to classify it in line shape. When I convert it into line, the attributes turn out to be one (one row ...
1
vote
1answer
540 views

Polygonizer plugin for QGIS halts in Windows?

I've had some success and some problems using the Polygonizer plugin in the past. I'm using Polygonizer 2.1 in QGIS 1.8 on Windows 7. I'm aware there are sometimes problems using Polygonizer in ...
1
vote
3answers
4k views

Using Plat Plotter - Calculate Curve Table feature given an arc and radius

Plat Plotter has a Calculate Curve Table feature that generates a sequence of points for use in drawing plot lines. To put another way, it converts a curve into several short, straight segments ...
1
vote
2answers
5k views

Converting Points to Lines in ArcGIS Desktop and retaining attributes of both start and end points?

I have a table with animal location points. I need to calculate movement distances between points from the same animal. So I thought I would create lines from the points, which are linked by an animal ...