Questions tagged [intersection]

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

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1answer
19 views

Improving performance of shapely crosses

I am unsure if this is the fastest way to test if LineStrings cross each other. Is there a better method. for line_1, line_2, in itertools.combinations(lines, 2): crosses = line_1.crosses(line_2) ...
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0answers
20 views

Adjecency matrix with road intersaction to the power of 3

I got the following code: line_gdf = Crewe.iloc[0:2500] ma = line_gdf.geometry.apply(lambda g: line_gdf.intersects(g)) lll = ma < 1 # Where values are low ma[lll] = 0.0001 # All low values ...
2
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1answer
2k views

Fast intersection of a list of polygons with a bounding polygon using Shapely

I have a list of Shapely polygons which I need to find the intersection of each with a bounding Shapely polygon. Not all the polygons in the list cross the boundary of the bounding polygon so I only ...
2
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1answer
23 views

PostGIS Recursively Finding Intersections of Polygons to Determine Clusters

My dataset currently contains about 15.000 buildings which partially touch each other. The objective is that those which do touch should belong to a cluster. This "basically" works but the main issue ...
2
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1answer
200 views

Finding shortest distance from point(s) to number of polygons at varying angles using shapely?

My aim is to calculate the distance a point is from land in Python, trying to replicate the functionality of fetchR. Given an origin and distance, I create shapely LineStrings which radiate out from ...
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2answers
49 views

Identifying which lines cross building polygons using ArcMap?

I have the following lines generated from coordinates with XY to Line. I would like to select and delete the lines which cross and are contained within the buildings. I need to do this to find the ...
1
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0answers
33 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 ...
4
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1answer
282 views

Assign order number in which line intersect polygons

Is there any tool (plugin) for QGIS to assign order (sequence) number of line intersecting through polygons? At this moment I use a bit cumbersome solution which works but... I use Qchainage plugin ...
3
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1answer
44 views

Intersection tolerance error with Shapely

I am using Shapely to do a basic intersection operation. However, Shapely doesn't return the intersection line I am looking for. I though the reason might be Shapely's intersection doesn't have ArcGIS'...
2
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1answer
55 views

Aggregates Functions - QGIS - Calculating Area Explained

I've been reading through question and answers on the Aggregates Function, but have been unable to obtain a clear understanding and solution to my problem. I have a polygon grid ("Grid 4km") and I ...
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3answers
14k views

Ignoring invalid input features with Intersection tool in QGIS?

In QGIS 2.18, when I used the Vector > Geoprocessing Tools > Intersection tool, I was able to check an option which said "Ignore NULL geometries [optional]". Now I've downloaded QGIS 3.2 and that ...
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1answer
1k views

Calculating intersect of two shapefiles using QGIS [duplicate]

I have two shapefiles. 1. the clinic buffers 500m area. 2. the postcode area. Is there a simple way to calculate the intersect two shapefiles ? I'm using QGIS Dufour. I tried to use fTools to ...
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0answers
21 views

Setting topology rules to connect short lines aross complex intersections

I have a polyline SHP with a bunch of very short lines (less than one meter length). Is there an automated way to force the short lines to connect to a neighboring line at complex intersections? ...
1
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0answers
20 views

Choosing Clip or Insersect tool in QGIS? [closed]

I am doing a analysis but I have information which is not available in all disagregation levels. I mean, some data is at a national level, other is at subnational level and other is in district level. ...
1
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0answers
15 views

Create grid with a prespecified number of cells inside a shapefile with R

I need to create a grid inside a shapefile with a fixed the number of cells n (inside the shapefile). I tried a few stuff see bellow but nothing worked so far. Any ideas? The data shapefile can be ...
1
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1answer
793 views

Intersecting overlapping polygons individually in ArcGIS Desktop

Map Layers: Census Tract ShapeFile with Population Data Set of Store Locations with 5 Mile Buffers (Significant Overlap Between Buffers) I have create feature layers for both and I am trying to ...
3
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1answer
330 views

ST_Intersection between MultiPolygon tables leads to gaps, missing intersections

I am trying to intersect two MultiPolygon tables, which are in the same UTM projection, and calculate the area of their intersections. I am getting some surprising results when I examine the ...
3
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0answers
73 views

Find a centerline of an intersection between two irregular shaped polygons

I have two irregular shaped polygons that overlap each other at least in at two points. I want to first find the intersection area between all of them, then for the polygon pair that intersects I want ...
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0answers
38 views

Finding out if crossroad or 3-way-intersection

I'm trying to find out the type of a crossroad / intersection in overpass by given coordinates (simple 4-way-crossroad or 3-way-intersection aka Y/T intersection). Wanted to count the way-id's I'm ...
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0answers
23 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 ...
0
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1answer
82 views

Overlapping two line problem

I want to check if 2 linestrings intersects (or overlaps) or no. I use turf.js overlap. Here are the results I want to get: CodePen 1- If only first or last points of line 1 intersects with first ...
2
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1answer
23 views

Using Geos C++ Library to return overlap and intersects [closed]

I'm running GEOS C++ Library v 3.6 on Fedora. I have a list of geometries I loaded from a shapefile and converted to geos polygons. The shapefile is large and I may be overlaying several ones to ...
8
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2answers
244 views

Tool that modifies number of vertices but not the feature itself

Do you know the reason, why some ArcGIS tools (like Clip and Intersect) modifies number of vertices, even if the feature is not modified itself? Like on the picture, I use Clip and Intersect on line ...
2
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2answers
4k views

Querying intersecting areas areas - Oracle Locator or Spatial?

My spatial database is Oracle. We are wondering if we can use basic Oracle Locator or need to get the more expensive, full, Oracle Spatial. My application's requirements include having to be able to ...
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0answers
54 views

Spatial intersection of features (Oracle Spatial) with a line stored in a local gml file?

Interesting sites are stored as polygon features are stored in an Oracle Spatial read only dB. I have a local GML file containing a line (EPSG:31370 - corresponding to a trajectory over a couple of ...
2
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1answer
44 views

Check if points that share attribute intersect polygons

How to check whether points started in red and ended in a blue polygon (and vice versa) while sharing the same attribute? To check if the first location of the unique ID is in one polygon and last in ...
2
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1answer
54 views

Points along lines at set elevation intervals [closed]

I am looking for a way to create points along lines (roads) at set elevation differences (0.5m height differences) using QGIS.
4
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2answers
6k views

How to fix overlapping polygons using ArcGIS for Desktop?

I'm using ArcMap 10.3. I have a layer of different land use types. After calculating the percentage of each land use in the catchment using tabulate intersection, I found out that the percentage of ...
1
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1answer
62 views

Finding percentage of intersection in polygon

For two given polygons generated in this code, how do I find the percentage of intersection on the rectangle? [The polygon was created using the Alphashape function] (Linked to Finding points of ...
1
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0answers
47 views

Finding points of intersection in polygon?

For two given polygons generated as shown below, how do I find the points that are intersected on the rectangle by the circle? [The polygon was created using the Alphashape function] (Similar to ...
3
votes
2answers
125 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 ...
2
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1answer
114 views

Trimming road end at the intersection?

I have a road centerline that I have used to create buffers that represent road area. Now I need to fix the intersections. As you can see on the picture, if the road end is touching the non-end of the ...
1
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3answers
112 views

Variable Buffer on Street Centerline using ArcGIS

I have a street centerline file where all road segments have a functional class of Arterial (A), Collector (C), Local (L). I also have a point file of each intersection. I would like to do a crash ...
1
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2answers
252 views

Seeking solution for PostGIS raster 3d intersection?

Is there a PostGIS solution to a 3D intersection between a DEM raster (with elevation in band 1) and a 3D line? Here are some facts: Rasters only support 2D processing so I can't use ...
0
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1answer
225 views

Length of intersections from a linestring and a grid shapefile by using Python GeoPandas & QGIS

I am using Python GeoPandas and I have two shapefiles. One of them is a grid file containing equal polygons. The other shapefile is a linestring file with several lines and its Attributes. The idea ...
1
vote
1answer
75 views

Replicating“Intersection” function in QGIS using PostGIS queries

I have two multipolygon shapefiles that I've imported into my PostGIS database - one of congressional districts (cds) and one of US counties (ctys). Below shows the counties in blue and the districts ...
8
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0answers
219 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 ...
0
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1answer
36 views

Stop SQL Server selecting outside buffer

I am trying to select all the parks within 200m or a railway. I can easily create and visualise the 200m buffer. However when i try and find only the parks that intersect it i get all parks returned,...
0
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1answer
38 views

AGOL Web App - user selects a polygon and finds Web Maps that intersect it

I'm working on an ArcGIS Online Web App. Basically what I want the user to be able to do is: Select a state from a basic US state polygon map From that state selection, the user then chooses a ...
0
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0answers
67 views

Determining if Raster and Polygon intersect using ArcPy?

I have a folder of rasters (.tif) and I want to determine which rasters intersect a polygon. The rasters are single band with a value of "1" while the rest of the extent has a no data value (coloured ...
1
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1answer
40 views

Building query with st_shared in QGIS

I have a table with county polygon boundaries (named "counties"). I need to build a query that identifies a particular county as well as any adjoining counties that share the same border. Have tried ...
8
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7answers
7k views

Intersection algorithm that correctly handles 180° meridian and poles?

Is there a well known intersection algorithm that correctly handles 180 meridian and poles? For example, let's say we have a list of latitude and longitude values that represent Antarctica. Let's ...
1
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0answers
40 views

How to delete vertex and keep topology

I work with line vector data (road network).The lines (roads) includes several vertexes. I would like to have for each line only nodes - at the end of line, or at the intersection of n lines. How can ...
0
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1answer
51 views

Saving borough boundaries as MultiLineStrings or MultiPolygons?

I am creating a database in PostGIS and I have a column that will save the boundaries of boroughs. The app will later query the database, asking what points, lines or polygons are inside those ...
0
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1answer
139 views

Summing number of intersections with separate buffer layer using QGIS?

I have two layers: 1) census blocks, and 2) point data. My goal is to calculate the sum of the point data within the census blocks to eventually create a choropleth map and to run regression models ...
7
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2answers
11k views

OGR Layer Intersection

I am using what I would describe as the most primitive method of doing intersection with OGR. The short script below describes how I do it. Is there a best way of doing this? from osgeo import ...
0
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0answers
15 views

Split height data based upon grid? (Same as Create Grid, Intersection, Split Data for Vector)

I have vector data for a large area that I have split into 2km x 2km layers using Create Grid, Intersection, and split, within the vector menu. I've downloaded STRM data for the whole area. I'd like ...
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0answers
59 views

Faster calculation of Shapely polygon-line intersection

I am running a Python Shapely where I have a rotating and translating polygon for which I obtain some probe signals in the following way: for theta_index, theta in enumerate(thetas): rotated = ...
1
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1answer
168 views

Determining if Point is in Polygon using PostGIS?

I want to check if a point is inside a fenced polygon. INSERT INTO polygon (name, geom) VALUES ('test', ST_GeomFromGeoJSON('{"type": "Polygon", "coordinates": [[0,0], [0,5], [5, 5], [5,0]]}')); ...
3
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1answer
362 views

Getting Unique Intersections of Multiple Polygons Efficiently in Python

I would like to get a list of all polygons that are intersections of other polygons. However, that list of intersections cannot self-overlap. For example, if I have a triple Venn diagram, I would ...