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Questions tagged [intersection]

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

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10 votes
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Defining partial or complete overlap with QgsSpatialIndex

I'm working on adding some functionality to a QGIS plugin. It currently uses a QgsSpatialIndex to efficiently compute whether the features of a vector layer intersect (potentially millions) of ...
alphabetasoup's user avatar
6 votes
0 answers
120 views

Why won't my points (that I created by intersection) intersect with the geometry they've been created from?

I created a set of points by intersecting a linestring layer with the boundary of a multipolygon layer like this: CREATE TABLE freiraumkataster_grenze AS SELECT gid, ST_CollectionHomogenize(...
Janne Jakob Fleischer's user avatar
6 votes
1 answer
2k views

Finding Intersection of Two Circle given Lat/Lon and radius?

I am attempting to calculate the intersection of two circle on the Earth with a given latitude, longitude and radius. I started with this Calculating intersection of two Circles? These circles will ...
Ryan crosser's user avatar
5 votes
0 answers
126 views

Clip completely overlapping polygon(s)

The shapefile that I'm working with (in QGIS) has over more than 250k polygons. But unfortunately a lot of the polygons are overlapping. The focus of my challenge is to delete or clip the polygon ...
Mark 's user avatar
  • 71
5 votes
0 answers
461 views

Intersection and area calculations in geographic vs. projected coordinates

I think one should do intersection calculations when layers are in the same coordinate system, and one should do area calculations in the appropriate projected coordinate system. The order matters, ...
JPC's user avatar
  • 71
4 votes
0 answers
486 views

Create lines to connect vertices in QGIS

I have a file that marks street edges and want to connect "crossing" points automatically. Image 1 shows the street edge, Image 2 shows the desired result. Is there a plugin or method I can use to ...
jpmaniac87's user avatar
4 votes
0 answers
999 views

TopologyException issue when doing intersection in GeoPandas

When I do overlay processes like intersection, I mostly get: :TopologyException: found non-noded intersection between LINESTRING (229971 4.39944e+06, 229971 4.39944e+06) and LINESTRING (229971 4....
a9e1's user avatar
  • 59
4 votes
1 answer
719 views

GeoPandas cumulative value sum for intersecting polygons

I have a GeoJSON file for all of the tax areas in the state of Utah. I read it into a GeoPandas dataframe. Now each row represents a tax area polygon. Many of the tax area polygons overlap each other....
cheevahagadog's user avatar
4 votes
0 answers
501 views

How to Simulate Venn Diagram of Buffers using QGIS?

For the sake of simplicity, suppose I have only 2 points on one layer. Point A have population of 100, and point B have population of 150. I do find buffer of these 2 points and it is intersect. I ...
neizod's user avatar
  • 141
3 votes
0 answers
106 views

Split an array of GeoJSON linestrings (from Overpass Turbo) into an array of road intersections

I've got a query that pulls in a bbox of GeoJSON LineStrings representing roads from the Overpass Turbo API. I'm working in Typescript and have been using the TurfJS library extensively. I want to ...
yellow-saint's user avatar
3 votes
0 answers
293 views

Selecting lines between two points using ArcMap

I have two layers: One representing intersections in a city; and the other representing the road network. As shown below, I'd like the ability to select road segments provided two intersections. That ...
John's user avatar
  • 31
3 votes
0 answers
538 views

Smart way of finding the polygon intersection of a huge GeoJSON file with a small GeoJSON file without looping through all polygons

I have a huge GeoJSON file (over 300MB) which has multiple different polygons. Also, I have a very small GeoJSON file with only one polygon that doesn't have more than ten points. Using the ...
raylight's user avatar
  • 1,153
3 votes
0 answers
108 views

Calculating population within a circle excluding intersects with shapely

I have a data of a centroid and a count: centroid population id 0 POINT(38.9081 77.0349) 9004.0 0 1 POINT(38.8521,77.0377) 517.0 1 2 POINT(38.9081 77.0377) 10369.0 ...
Feyzi Bagirov's user avatar
3 votes
0 answers
67 views

QGIS 3.4.11: intersecting vector data/list all land cover classen

I have a question regarding QGIS 3.4.11. For research purposes I need to intersect two vector data - one polygonized raster (with land cover classes)/mulitiple polygons shp and one point shp (buffers ...
ben0's user avatar
  • 39
3 votes
0 answers
531 views

Assign area of polygon to raster cell. Effective way in Python

I have quite interesting task to resolve, but my solution is not effective, so I am looking for some advice to improve my code. I have raster dataset covering Europe, in crs WGS 1984 (4326). The cells ...
Dorregaray's user avatar
3 votes
0 answers
96 views

Joining lines intersecting with only one other line?

I have road centerline file that is split into smaller segments. I need to make a node file. How can I join line segments intersecting only once - so I wouldn't join ones that have 3-4 intersections ...
jinha kim's user avatar
  • 329
3 votes
0 answers
483 views

Unable to compute intersection between two polygons using PyQGIS?

I have two polygons in different layers. I am trying to find the intersect between the two polygons. Below a figure showing my test case. I initially wanted to find the intersect between the green ...
Erik's user avatar
  • 31
3 votes
0 answers
398 views

Framing of WFS GetFeature request using polygon intersect filter

I am trying to frame a Web Feature Service GET Request applying the INTERSECT filter but I am getting the following error. : <ows:ExceptionReport xmlns:ows="http://www.opengis.net/ows" version="1....
Charu Manivannan's user avatar
3 votes
0 answers
1k 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 ...
master_of_mediocrity's user avatar
3 votes
2 answers
303 views

Query Z at intersecting point locations from a MultiPolygonZ?

I create a MultiPolygonZ geometry with ST_DelaunayTriangles(). select st_setsrid( ST_CollectionExtract( ST_DelaunayTriangles( ST_GeomFromText('MULTIPOINT ...
Dennis Bauszus's user avatar
3 votes
0 answers
100 views

Determining the first and last point that a polygon intersects

I have this... And I want to join those attributes to the polygon automatically: Because I'll have to replicate this on tones of those polygons. If this works I would like to know if it still works ...
Rui's user avatar
  • 97
3 votes
0 answers
333 views

How to compute (X,Y,Z) of a point from given attributes

Is there a way to compute the geodetic coordinates (Earth Centered) of a satellite S(x,y,z). The original problem is to compute the footprint of an antenna, given the following information: Antenna(x,...
Etore Marcari Jr.'s user avatar
3 votes
0 answers
1k views

Intersecting vector data with raster data in PostGIS?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
Justin Swanhart's user avatar
3 votes
0 answers
832 views

Can't find point/polygon intersect using QGIS (Windows only)

Below I describe the method I am using. I have two machines: ubuntu linux, qgis 1.4 - intersection works WIN xp, qgis 1.8 - intersection does not work Hopefully, someone will find what I am doing ...
yair suari's user avatar
2 votes
1 answer
28 views

How to deal with concurrency when inserting polygons in a SQL table in a way that they don't intersect with each other

Problem: I have a table X, in which I am inserting polygons (ex: geometry data for a city). Before inserting them, I check if the input polygon intersects with any existing polygon in the table and ...
xorrax's user avatar
  • 21
2 votes
0 answers
75 views

Why is my custom aggregate function not returning data in the order I've specified?

I have a polygon layer where many features intersect each other. I want to flatten these overlaps and pick out attribute values according to a custom order. To do this, I've been using QGIS's Union ...
dericke's user avatar
  • 992
2 votes
0 answers
73 views

Detect intersection nodes between different highway types

I have a postgres database with OSM data imported in it using osmosis. The import process created a ways table that has the following columns: id | version | user_id | tstamp | changeset_id | tags | ...
Miflo's user avatar
  • 31
2 votes
1 answer
84 views

Calculating common area between shapefiles using GDAL

I'm looking for a way to get the intersection area between my shapefiles. Basically, I got three shapefiles from my .tif files like this: gdaltindex a.shp a.tif gdaltindex b.shp b.tif gdaltindex c.shp ...
Salvo's user avatar
  • 31
2 votes
0 answers
90 views

Cut lines when they cross another line via symbology in QGIS

I am currently preparing roads from OSM data. For this I want to display the roads with 2 lines at the roadside. I have set this without any problems via the symbol layer properties (see image). ...
Simon Hans's user avatar
2 votes
0 answers
57 views

Line has been split, total line is different from unsplit line using ArcGIS Pro

In ArcGIS Pro, I've done a intersect on a line based on an area boundary. When I compare the length of the intersected lines, it should equal the length of the original line. However there is a slight ...
BobbyGIS's user avatar
2 votes
0 answers
133 views

Using layers with different CRS in Intersection tool of QGIS

I've always thought that to intersect two layers, they needed to have the same CRS. Today, I tested the Intersection tool to intersect layers with different CRSs, and I was surprised to see that it ...
dangimar's user avatar
2 votes
1 answer
442 views

Compute the distance from a point to polygon given the point and direction

I want to compute the distance from a point to a polygon given the point and direction. Currently I am using shapely and defining a "somewhat" infinite line string. This is not ideal as I ...
jlcv's user avatar
  • 345
2 votes
0 answers
313 views

Measure length of shadow from object center in QGIS

I am trying to measure the length of object shadows in QGIS 3 in order to calculate the object's height. In order to know height (h) I will need to have: The length (l) of the cathetus (line from ...
Steffan's user avatar
  • 518
2 votes
0 answers
214 views

PostGIS - ST_Union + ST_Difference create extra line segment

Very similar to this question I have two multipolygons, which touch/overalp each over. please see this link for the multipolygon #1 and multipolygon #2 multipolygon #1 multipolygon #2 I ran st_union ...
Tony's user avatar
  • 41
2 votes
0 answers
77 views

PostGIS "thresholded intersect" or "signfiicant intersect" query

I've been working an application using PostGIS that needs to join the interior intersection of two different layers (made up of polygons and multipolygons). These layers have many shapes which are ...
James's user avatar
  • 21
2 votes
0 answers
76 views

ArcGIS - Percentage in Census tract to HUC

I’m trying to figure out the percentile of demographic value (minority %, poverty %, etc.) per watershed at HUC12 level. I was hoping that I can somehow convert the values from census tracts into HUCs....
Susan's user avatar
  • 21
2 votes
1 answer
360 views

How to add intersection vertices to a ShapelyLinestring?

Assume that I have two shapely LineStrings. I want to find their intersection and then add the intersection point as vertices into the respective LineStrings. from shapely.geometry import LineString #...
J.Galt's user avatar
  • 129
2 votes
0 answers
235 views

Is it possible to prevent ogr2ogr from generating a shapefile if no records are returned from the given intersection?

I am generating shapefiles from a geodatabase file with ogr2ogr via the spatialite dialect using the following command: ogr2ogr -f "ESRI Shapefile" ./clipped.shp -dialect sqlite -sql "...
L.Youl's user avatar
  • 121
2 votes
0 answers
129 views

Problem with intersects operator in Postgres

I have this table below CREATE TABLE public.geometry_polyline_volume ( id serial not null primary key, distance float not null, height float not null, coordinates ...
chatzich's user avatar
  • 251
2 votes
0 answers
51 views

PostGIS intersected polygon fails on contains

I have two functions, first I check if a polygon is within a defined polygon. If it's not, but on the border, I cut it with ST_Intersection, and get a new polygon. If I check the result, I get that it ...
buboreka's user avatar
  • 396
2 votes
0 answers
371 views

Improve OGR SQL query for polygon intersection using WKT geometry

I want calculate the intersected area between a shapefile and WKT geometry. My target big layer: a.shp My query small layer: 'POLYGON((1150046 1264030, 1160100 1263793, 1160079 1260606, 1150218 ...
gonzalez.ivan90's user avatar
2 votes
0 answers
306 views

Calculating share of overlapping areas via aggregate function in a virtual field

I'm trying to calculate the shared area for several overlapping areas. I need a dynamic solution in order to get automatically calculated statistics when drawing new polygons. The target area is in ...
marc_mk's user avatar
  • 129
2 votes
0 answers
432 views

T-SQL Invalid Geometry Created by Intersection

I have two sets of geometries (A and B) in SQL Server 2016. I want to determine the overlap areas of those geometries from set A that intersect set B. Most of the time this code works: SELECT a....
AJSmyth's user avatar
  • 403
2 votes
0 answers
1k views

How to speed up 'intersection' tool for big amount of data?

I can't figure out how to work with a large dataset. The problem is: I want to know how many points (over 700 000 adresses) are within a polygon layer (it's made out of 5 layers, train noise)(they are ...
Guestname's user avatar
2 votes
0 answers
628 views

Nearest point does not intersect line in 'sf' R package

This is a similar question to my recent questions on how to find the nearest point along a polyline and how to split a polyline by an intersecting point using only the sf package. My question has ...
bcaradima's user avatar
  • 837
2 votes
0 answers
770 views

Length of the boundary intersection between two polygons in R

I am trying to find the length of the border shared by two polygons. I have run cleangeo on these shapefiles. There were no flags that came up. I have looked through several other posts on the topic ...
John Asplund's user avatar
2 votes
0 answers
85 views

Find the intersecting area of more than 2 polygons in QGIS

I have a map of 7 species distributions. I want to create polygons of the area where all 7 overlap, 6 overlap, 5 overlap etc. I created a polygon of where any 2 species overlap using the intersect ...
Anna Coleman's user avatar
2 votes
0 answers
177 views

QGIS processing algortihm crashes in python console but works manualy

I am loading two layers from PostGIS database and I am trying to run 'qgis:intersection' algorithm with them. Execution of the algorithm through the python console initially works but crash after 2-3%....
D.Betsov's user avatar
2 votes
0 answers
630 views

3d Intersect query compatible with GeoTIFF/DEM?

When researching this topic I haven't been able to verify if it's possible to make spatial 3D Intersect queries between a vector polygon with z-values and GeoTIFF/DEM file holding the elevation values?...
johlund's user avatar
  • 637
2 votes
0 answers
212 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 ...
eos's user avatar
  • 295

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