Questions tagged [intersection]

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

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votes
1answer
79 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
64 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 ...
27
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3answers
18k 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 ...
1
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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 ...
0
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0answers
24 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
22 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
25 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
819 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
votes
1answer
346 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
117 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 ...
0
votes
0answers
46 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 ...
1
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0answers
30 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
143 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
votes
1answer
45 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
votes
2answers
250 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
votes
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 ...
0
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0answers
66 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
votes
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
votes
1answer
66 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
vote
1answer
132 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
73 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 ...
1
vote
3answers
128 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
265 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 ...
1
vote
1answer
87 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
239 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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0answers
102 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
vote
1answer
41 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 ...
9
votes
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
53 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
votes
1answer
141 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
votes
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
votes
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 ...
0
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0answers
98 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
vote
1answer
182 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
votes
1answer
496 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 ...
1
vote
1answer
53 views

How to get the intersected region(s) of multiple polygon layers

I have multiple layers with polygons. I want the regions that are intersected by all the polygons. The shared, common regions. An example use case would be finding the shared area of multiple raster ...
0
votes
0answers
280 views

Using Geometry commands in MS SQL Server 2008?

I am looking to find the most effect way to use SDE and ST_Geometry SQL commands. Can anyone tell me how/what commands I might use to perform a spatial query in MS Sql Server 2008, to Select ...
1
vote
1answer
30 views

Unioning a set of intersections [closed]

I'm working with two datasets: a set of precincts and a set of census block groups. The census block groups include water; the precincts don't. I would like to trim the census block groups to get only ...
2
votes
1answer
90 views

Multipart geometry after pyqgis-3 intersection()

I'm trying to intersect two polygons with intersection() function of QgsGeometry (pyqgis-3). The problem is that the result is a multipart polygon instead a single part polygon and QGIS doesn't allow ...
1
vote
1answer
140 views

QGIS Intersection tool not allowing Save file as Shapefile

In QGIS 2.16.2 I am trying to intersect two Shapefiles to create a third Shapefile, however the Intersection tool is only allowing Save file as DBR, CSV, XLSX or ODS - not SHP. One of the Shapefiles ...
13
votes
3answers
41k views

Create a new layer from overlap between two layers?

I'm new to desktop GIS, and will try to ask while lacking the proper terms from the GIS lingo: If QGIS was like Photoshop I would like to make a selection from one layer, and then match that ...
2
votes
5answers
10k views

How to get intersection point from two lines (two coordinated points and two bearings)

I have tried for ages to find the algorithm for getting the coordinate of two intersecting lines from two given coordinated (latitude and longitude) points. As the picture below suggests, I have two ...
1
vote
1answer
43 views

Getting area covered by intersection or junction?

I need a way to get following information for each intersection or junction in Berlin: latitude and longitude area covered I could get all Junctions from openstreetmap as nodes, which would give me ...
0
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0answers
17 views

Selecting street segments (polylines) based on intersections with others and adding value to its field from Excel table?

I have a shapefile of city streets polylines and an excel sheet with similar data. I need to select a street segment based on the two segments it intersects. Then I add the value from the "ID" field ...
1
vote
0answers
56 views

Identify intersections and assign them to one of the features in a single layer

I have a single SHP-layer (12,810 features) and want first of all to identify intersections (incl. duplicates --> features with identical geometries). In the next step I want to delete/clip these ...
1
vote
1answer
64 views

Select shapes in one layer that overlap with shapes from another layer?

This question is a duplicate of this: How to select only polygons that overlap with another layer? But in my question I want to know how to do this in QGIS not in ArcGIS. I want to be able to select ...
2
votes
1answer
55 views

Generating map with polygon aggregation in PostGIS

Generate the map of federal units from the municipalities map in PostgreSQL with PostGIS. Example below: The table has only the geometry information and the "id". I tried: SELECT st_union(m.geom) ...
20
votes
5answers
51k views

Finding if two polygons Intersect in Python?

I'm looking for an algorithm, a high level solution, or even a library which can help me determine if two polygons intersect, in Python. I have the vertices of the two polygons (These are single part ...
1
vote
3answers
46k views

Cropping basemap to specific area using ArcGIS Desktop?

I have a base map from ONS of the entire UK and on another layer I have a boundary outline for the smaller area which I want to crop the base map to. How do I delete everything outside of this small ...

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