Questions tagged [intersection]
Use this tag when asking questions related to where features overlap.
234
questions with no upvoted or accepted answers
10
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0
answers
362
views
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 ...
6
votes
0
answers
119
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(...
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 ...
5
votes
0
answers
125
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 ...
5
votes
0
answers
438
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, ...
4
votes
0
answers
485
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 ...
4
votes
0
answers
977
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....
4
votes
1
answer
700
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....
4
votes
0
answers
495
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 ...
3
votes
0
answers
105
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 ...
3
votes
0
answers
285
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 ...
3
votes
0
answers
533
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 ...
3
votes
0
answers
106
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 ...
3
votes
0
answers
66
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 ...
3
votes
0
answers
509
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 ...
3
votes
0
answers
95
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 ...
3
votes
0
answers
482
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 ...
3
votes
0
answers
393
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....
3
votes
0
answers
997
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 ...
3
votes
2
answers
296
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 ...
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 ...
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,...
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 ...
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 ...
2
votes
0
answers
70
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 ...
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 | ...
2
votes
1
answer
80
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 ...
2
votes
0
answers
87
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). ...
2
votes
0
answers
55
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 ...
2
votes
0
answers
118
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 ...
2
votes
0
answers
412
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 ...
2
votes
0
answers
301
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 ...
2
votes
0
answers
209
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 ...
2
votes
0
answers
76
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 ...
2
votes
0
answers
72
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....
2
votes
1
answer
342
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
#...
2
votes
0
answers
227
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 "...
2
votes
0
answers
128
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 ...
2
votes
0
answers
50
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 ...
2
votes
0
answers
363
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 ...
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 ...
2
votes
0
answers
405
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....
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 ...
2
votes
0
answers
614
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 ...
2
votes
0
answers
762
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 ...
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 ...
2
votes
0
answers
176
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%....
2
votes
0
answers
624
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?...
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 ...
2
votes
0
answers
64
views
How to get lengths between intersecting points
I have a route that goes all the way along the project scope (Route A) and then multiple other alternative routes that intersect Route A at different points (See picture Here). I want to get the ...