Questions tagged [intersection]

Use this tag when asking questions related to where features overlap.

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1answer
432 views

Group intersecting/overlapping com.vividsolutions.jts.geom.Polygon

I have list of geometry type in a database or: List<com.vividsolutions.jts.geom.Polygon> polygons Is there any JTS Topology Suite method or PostGIS function which would output intersecting ...
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1answer
95 views

Cropping a grid of polygons to a single polygon gives an odd result

I am trying to create a grid over a polygon from which I can choose a random subset of cells for sampling. The problem occurs when I crop the grid, which I am converting to polygons, by the polygon ...
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0answers
226 views

ArcGIS Split Line at Point Tool splitting at intersections - faulty output?

The screenshot below shows a 'brown_FC' of brown lines generated by this script which i want to be split at the intersection points with the 'green_FC'. This works just fine if i take the 'brown_FC' ...
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0answers
262 views

PyQGIS - QgsSpatialIndex.intersects returns unexpected results

I have a polygon and a line. The line starts very close to the polygon but the end vertex is further away. I create a rectangle around start and end vertex. The spatial index of the polygon is used ...
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2answers
602 views

Get features inside a polygon from a WMS Layer in OpenLayers2

i have found some answers for this and that and the most promising approach seems to be this one here: OpenLayers - Get features inside a polygon But i have no clue how to rewrite this to suite a ...
3
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1answer
101 views

Define precision in geometric predicate methods in PyQGIS

It is possible to define precision for geometric predicate methods, such as: intersects (), contains (), equals (), touches (), overlaps (), within (), crosses() For example, I'd like to set the ...
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0answers
21 views

What is the efficient way to find the top-most images of a Landsat-8 mosaic with latest data on top?

I'm building a simple mosaic of Landsat-8 for a region of interest (a bounding box) for a time period, so that the latest data would be put on top of the mosaic. I've found 100 scenes with cloud cover ...
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0answers
55 views

Coordinate System for 3D Flight Path?

I want to build a algorithm (Matlab), which detects if a 3D flight path intersects with clouds (cloud=cube at first). Flight path waypoints are on a great circle and between waypoints I move on rhumb ...
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0answers
79 views

Two geometries not at same place

In the picture1 shown there is a linestring which is Area2 and a buffer of linestring which is Area1. I want to include Area2(linestring in picture) in the buffer but I cannot increase the size of the ...
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1answer
373 views

How to create a buffer from WMS / Google Maps API?

I have a collection of points from a WMS of GeoServer I need to show a buffer. Let's assume that these points are locations of commissaries and that the buffer is the 'area of responsibility' around ...
3
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2answers
432 views

intersection in postgis takes hours and hours to run, why?

I have a table with approximately 500,000 records that I am trying to intersect with a table that has about 30,000 records. It was running for 11 hours until I finally stopped it. Why would this ...
2
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2answers
294 views

Overlay in QGIS? [duplicate]

I'm new to QGIS. I have constituency maps in India and block maps from 2001 census. Each constituency usually consists of a few blocks, but in some cases, a part of a block may belong to one ...
2
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1answer
169 views

Identifying points on the intersection of three roads in PostGIS

I have two tables point and roads in my PostgreSQL 9.5 database. Some of the points lie on the intersections of three roads (line segments). The sample scenario is as follows: I want to identify all ...
1
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1answer
227 views

Calculate polygon intersection without boundary intersections

I'm trying to intersect the shapefiles for US congressional districts and US counties. I can intersect manually (Vector->Geoprocessing Tools->Intersect) or with python (processing.runalg('qgis:...
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2answers
748 views

Zonal stats for two polygon layers: calculate proportion of feature cover within polygons

In order to calculate land cover diversity within defined patches, I need the coverage proportion of each landcover type for each patch. So I am searching for something similar to the zonal stats tool ...
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0answers
49 views

Intersect ignores joined fields

In QGIS, I use the intersect function provided by the saga algorithms. The resulting shapefile contains the original attributes but misses joined fields of the input layers. Is there an elegant ...
1
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3answers
503 views

How can I highlight or color polygons intersecting another layer based on certain values?

I have one layer of polygons that stretch across the U.S., and another layer of all counties in the U.S. In the counties layer is a column with population density for each county. What I am trying to ...
3
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1answer
84 views

Draw Bridges at intersections with correct angle with PyQGIS?

I have a road layer and a river layer. I want to draw bridges at the intersections with correct orientation of the bridge (parallel to the road). I have found out that you can use the "Vector->...
2
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0answers
120 views

Is there any faster ways to count intersections between lines and polygons for large datasets with python? [closed]

I utilized the Polygon.inetersects() method to judge intersections between line dataset and polygon dataset with "shapely", but it turn out to be slow but I have a large number of data. Can anybody ...
1
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1answer
111 views

Unable to intersect a shapefile with a set of points

I have a set of 1000 urban points that I'm trying to intersect with a classification result to find the accuracy but I keep getting an error "GEOS geoprocessing error: One or more input features have ...
2
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1answer
363 views

Unexplained coordinates mutation with readOGR in R

I am trying to intersect two spatial objects in R (point and polygon) while preserving the contained information in the dataframes of both. However, the intersection produces an empty polygon, while ...
3
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1answer
807 views

Intersecting lines to get points in geopandas

I'm trying to use GeoPandas to generate points of intersection between two linear shapefiles. For example, I have a shapefile of pretend pipelines (red) and some crossings (blue). What I would expect,...
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0answers
366 views

Closest point to road intersections with GeoPandas and Shapely [closed]

I have a geopandas dataframe, where each record's geometry field is made up of a LineString. Each LineString represents the points which make up a road. I'd like to find the locations of all road ...
2
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2answers
3k views

Intersect polygons

I have the following situation: two layers that I want to intersect. The first layer has polygons over agricultural areas (blue polygons). The second one is the Study area (green polygon). I want to ...
3
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1answer
252 views

PostGIS: Get Disjoint Geometry

I have two polygons, I want to get the area which does not intersect. I looked at st_disjoint, it returns a boolean, I need a geometry. How do I accomplish this? Below is my code which gets the ...
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0answers
174 views

Snapping boundaries in PostGIS [duplicate]

I have two polygons in PostGIS that have incongruities. One polygon (the yellow one) is legal county boundaries. The other polygon (blue) is essentially neighborhoods. 98% of the lines align perfectly....
2
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2answers
673 views

Get Intersections of polygons in same layer in R (or Qgis)

I am trying to get the intersection of the following buffers in R: I know that for two shapefiles with gIntersects or st_intersection I can get the intersected areas between two shapefiles. However, ...
3
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1answer
7k views

Intersection error QGIS - invalid geometries that are actually valid

I'm trying to intersect two vector layers (having the same CRS EPSG:4326 WGS 84, in QGIS 2.18.10) but I get this error in the log: Input layer A contains invalid geometries (feature 52). Unable to ...
1
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1answer
315 views

Using intersection tool with geodatabase and vector layer in QGIS

I want to use the intersection tool in QGIS version 2.18 for two layers: Corine land use data downloaded from: http://land.copernicus.eu/pan-european/corine-land-cover/clc-2012 (a geodatabase, vector ...
1
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1answer
221 views

In PostGIS how can I do an ST_Intersection() search with a GEOMETRYCOLLECTION Geography field?

I have a Postgres table "files" with a lat/lon location field of type geography(GeometryCollection,4326). Right now the field only contains lat/lon polygons. I have succeeded in creating a gist index ...
0
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1answer
121 views

Obtain new polygon outline from 2 intersected polygons?

There are 2 polygons intersected. I can get a intersected small polygon by using "ST_INTERSECTION(geom, geom)". But I want to outer join the polygons like the uploaded image.
3
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1answer
138 views

Addresses within radius of vector layer in QGIS

I want a CSV file of all addresses that intersect with historical stream features. Currently, I have 3 datasets (see my blog) for this in QGIS 2.16.3 (MacOSX): a layer (.gdb) of historical stream ...
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0answers
30 views

a kind of intersection to compare color areas of 2 layers (ol4) - but how?

Hopefully anyone can point me to something to get this done ... cause its just a WMS and not a webGIS (ol4) Imagine: We have two tiled choropleth-maps and we want to compare areas of both. They have ...
10
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1answer
4k views

Geopandas Line Polygon Intersection

I'm trying to find where multiple lines intersect a polygon for two different geodataframes: from shapely.geometry import Polygon, LineString import geopandas as gpd polygon = Polygon([(0, 0), (1, 0)...
5
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2answers
1k views

Adding attribute features from the intersection of a grid with a point shapefile?

I want to calculate the frequency of observation of an animal in a forest habitat within the different zones of my study area. To do this I will use the simple equation (number of individuals)/(survey ...
1
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0answers
142 views

Efficient way to identify the many points at which a large set of shapely LineStrings intersect?

I have 10,000 shapely LineStrings in a geopandas GeoDataFrame. What is an efficient Python plus shapely (and/or optionally geopandas) way to produce a list of all the points at which these lines ...
4
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2answers
500 views

Getting quantity of intersecting lines of polygons in QGIS?

im looking for a way to get the quantity of lines from a line-layer that intersect the different polygons of a polygon-layer; I have: One line-layer with a clutter of lines, defined by ID, which ...
0
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0answers
41 views

Performing multilayer intersection in QGIS? [duplicate]

This question on Multilayer intersection in QGIS was asked by "julsbreakdown" a year go. But I am a newbie and I am not really sure how it works with SQL as suggested in the responses. And I am using ...
1
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2answers
241 views

Merging two road layers

I'm looking to merge two road layers. I am interested in the traffic volume in the second layer. The roads do not lay exactly on top of each other. The issue is that sometimes when there is an ...
0
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2answers
89 views

Extraction of Digital Terrain Model Intersections

I have two digital terrain models in ESRI ASCII (.asc) format. Their elevations intersect in multiple places. How can I extract the intersection of these two DTMs as a polyline or polygon shapefile? ...
4
votes
1answer
153 views

Geography ST_Intersects causes “Boom! Could not generate outside point!”

I'm trying to find where a user is based on their point and a table of multi polygons. I currently have: SELECT u.name l.name FROM users u INNER JOIN locations AS l ON ST_Intersects(u.location, l....
3
votes
1answer
139 views

Snap lines to polygon verticies at interscetion

I'm trying to figure out a way to snap lines to a polygon layer, but only at the intersecting point. Here is a sample picture of what I'm working with. I have a layer of polygons and a line string ...
2
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0answers
399 views

QGIS not recognizing special characters and problem with intersection?

Started playing with QGIS recently and I have encountered a problem. I have a layer with administrative areas of my country and when adding it the encoding is set to UTF-8. When I open its attribute ...
4
votes
1answer
148 views

ST_intersection returns erroneous polygons

I am trying to perform a clip by attribute in PostGIS between two shapefile containing 3000 polygons. Both shapefiles are free of errors (checked with topology checker), both shapefile are using EPSG:...
2
votes
1answer
309 views

Intersection between an angle and a polygon (postgreSQL + postGIS or Python2.7 + shapely + psycopg2)

I have a point geom feature (in wkb) in a PostgreSQL database table (with postGIS extension). There is also an azimuth value (degrees), as float, in an other field of the same table. How to perform, ...
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0answers
58 views

Methods to more efficiently generate regularly spaced research points inside of a multipolygon

I'm currently using the tried-and-true, but extremely slow method of: via QGis, generating two (ESRI shapefiles) of a large number of research points over a multipolygon which are generated using a ...
6
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0answers
296 views

How to remove overlapping features by percentage?

I have geometry records of type MultiLineStringZM and I am trying to INSERT new records that overlap some of the records currently in the table. If they were type MultiPolygon I could use ST_Area() as ...
1
vote
1answer
228 views

Grouping database results based on intersection using MySQL GIS?

I am using MySQL GIS (5.7.18). I have a number of locations in the database. I also have a number of other polygons (not in the database). I would like to perform a single query, intersecting all ...
1
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1answer
56 views

Does the TIGER geocoder intersect the polygons to match an address?

This post has a very good overwiew of how open source geocoders works. 1) Address normalization 2) String matching. 3) Interpolation. It shows a simple case of how interpolation in made, taking as ...
2
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1answer
937 views

Problems with intersecting two polygons layers in QGIS

I have two polygons layers, and I'm looking to find the % Area of layer A polygons that are placed inside layer B polygons. (some of them are totally inside ,so I expect to get the result "1", and ...