Where features overlap

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1answer
25 views

How to compute tabulate intersection in QGIS?

I have a base layer of census data in census tracts (polygons). I'm looking to intersect those tracts with a buffer layer but I only want to include those census tracts whose area is over 50% within ...
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2answers
187 views

Integrate grid and polygon of municipalities keeping the biggest municipality per cell with QGIS (or another)

I have a 9x9 grid and a polygon of municipalities of an extensive area of Brazil. My goal is to have a field indicating the biggest municipality per grid cell. I've been trying with intercept without ...
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0answers
25 views

Can a joined-layer have its attribute changed depending on what layers are selected/deselected?

Using QGIS, I have a polygon-grid layer which covers everything, Layer_All joined with 2 other grid layers: Layer_1 and Layer_2, both of which intersect at various points. I would like Layer_All to ...
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1answer
157 views

Counting self intersections of linestring using PostGIS?

Is there a way of using PostgreSQL + PostGIS for finding the number of self intersections in a linestring? I have a linestring that goes forward but in circles, and I need to find the number of times ...
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0answers
28 views

How to count unique lines intersecting with polygons?

Like u can see on the attached picture i did an intersection with a Raster (purple squares) and the red lines. What i need to know is the count of joins each line has for each square. What makes ...
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1answer
571 views

How to split a polygon using R

I have an irregular polygon which is a spatial object. I want to divide it into multiple polygons (say, n=25) with equal height. To show how I want to divide it, I've plotted grids on the ...
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1answer
322 views

Polygon color on intersect

Using OpenLayers, I am loading a large geojason file of about 4000 polygons. Once the polygons are loaded I want to draw a "LineString" on the map (already done and working). My challenge is that I ...
5
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1answer
526 views

Apportioning Points at a street intersection (arcgis or mapinfo)

I can't seem to find any evidence of this question, but I'm surprised by that, so pardon if this has been asked. If one is mapping crime location reports, by XY coordinates to streets, to create ...
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0answers
12 views

Determine lat/lon intersection on earth from point in space along 3d line

I have a known point in space with a lat,lon,alt. It has a camera with a line of sight and a angle of field of view. I can take the central point and calculate each corner vector of the field of view, ...
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0answers
26 views

How to intersect FeatureCollections in turf.js efficiently?

I've been playing around with turf.js and I'd like to use turf.intersect to intersect two datasets. My raw data are two polygon shape files so I converted them to geojson. I then tried to use ...
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0answers
22 views

Join polygons by plurality overlap

I'm trying to join two layers-- One is census tracts in Michigan; The other is school districts. Because there is no nesting in either direction (districts in multiple tracts and vice versa), I'm ...
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1answer
45 views

Oracle Spatial Returns Different Intersection Results with SRID Defined

I have a set of points and a set of polygons of which I am performing an intersection on to determine which polygon each point lies in. This was performed previously without the projection being ...
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1answer
38 views

Multi-part Geometrical Intersection error

I am working with intersection of polygon and line segments (continued from a previous question). When a Line intersects with a Polygon, the result is a LineString; When a LineRing intersects with ...
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1answer
41 views

Isolate features within buffer of another feature - QGIS

I have 2 shapes - one representing line features of pipes, another of roads. I would like to create a separate shapefile consisting only of the pipes that lie within 20m of the roads. Only the ...
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3answers
121 views

Query to find the Intersection coordinates of multiple Polyon

I am using the below Query to find out the intersection coordinates of 2 Polygon and its working fine,but how to use or modify the query to find the intersection area coordinates for multiple(or N ...
5
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2answers
441 views

Rgeos drops associated values when intersecting polygons

I am trying to intersect two SpatialPolygonsDataFrames and get a SpatialPolygonsDataFrame as the result. Unfortunately, using the gIntersection function from rgeos (which works impressively quickly ...
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0answers
36 views

How to cut parallelogram with intersecting line?

I have a very specific set of circumstances under which I need to break a parallelogram into 2 pieces. The parallelogram obviously always have 4 vertices and the intersecting line intersects the ...
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1answer
79 views

Line vs. Polygon Intersection Coordinates

I am working with Python, Shapely and Fiona... Is there any way where I can give in an input of a line shapefile and a polygon shapefile, and get a result of the intersection points and their ...
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1answer
271 views

Intersecting polygons in Oracle

Have a polygon in table 2 with its id, no and geometry. In table 1 I have polygons with the same fields. The polygon in table in intersects with a few polygons from table 1.What I am trying to do is ...
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1answer
26 views

Is this Intersect or Union algorithm associative?

Similar to Is the Intersection Operation Commutative? . Spoiler for that one: Intersection is commutative and associative. I've created an algorithm (in PostGIS but the theory would work in other ...
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1answer
116 views

How to calculate the intersected area from a layer with overlapping buffers in qgis

I need to calculate the area of landusetypes in 50m around various dots (all in one shapfile). My problem is, the buffers around the dots are overlapping each over in some places. I tried to ...
0
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1answer
94 views

PostGIS: Ensure Intersection of 2 Polygons results in a Polygon

I want to ensure that the result of ST_Intersection(polygon1, polygon2) is also a polygon. I initially filtering by ST_Overlaps(polygon1, polygon2) but that seems to only ensure that both features ...
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4answers
3k views

Lines that intersect vs. Lines that touch - how to distinguish?

How do I distinguish between these cases in ArcGIS 10? I am looking at the Trim Line function but that's not what I want (destructive). Case 1: Both endpoints of a line touch another line Case 2: ...
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1answer
86 views

PostGIS - Intersects feature to split into linestring

I would like to know if it's possible to intersect feature datasets (multipolygon, polygon, multilinestring and linestring) to get a result as a set of linestrings being split at each intersection ...
2
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1answer
21 views

Assigning values to a grid cell based on number of intersecting features

I need to create a grid that will include a single value for each cell which represents the total number of "stressors" intersecting that cell. So, the final product will be a 1km grid with cells ...
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7answers
2k views

Intersection algorithm that correctly handles the 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 ...
2
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0answers
56 views

arcpy.Intersect_analysis() returns empty result, but Intersect tool in ArcMap is succesful [closed]

I've got two large feature classes that I'm trying to perform an intersect on. Using the following python code, I get an empty output feature class: arcpy.Intersect_analysis(["Schools","Zips"], ...
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1answer
58 views

Finding an ogr2ogr equivalent of SelectLayerByLocation

So I'm trying to take individual grid point buffers and only select the regions that the points intersect with (via SelectByLocation). Generally I run the following code to: Explode multipart ...
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2answers
230 views

geospatial libraries like postgis

I'm pretty comfortable with postgis, but I realized that for part of my application, having a database is pretty heavy. I'd like to be able to take a stream of Point objects and check against an in ...
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0answers
22 views

How to check if there is an intersect between two coordinates? [duplicate]

I have two pairs of lat/lon (expressed in decimal degrees) along with their radius (expressed in meters). How can I see if there is an intersect between these two points? How should I deal with the ...
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0answers
108 views

convert lat/lon into meters

I have a database of latitude, longitude and radius in the following form: 48180759,11518950,19.0 Both latitude and longitude are expressed in degrees but then multiplied by 1e6 (or 1000000). ...
2
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1answer
67 views

Why are a polygon's vertices jumbled after importing KML into MySQL?

This is original KML : <Polygon><outerBoundaryIs><LinearRing><coordinates>104.700355,-3.056064 104.632127,-3.103623 104.608924,-3.103169 104.570166,-3.102411 ...
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1answer
80 views

How to connect centroids of lines sharing the same intersection in QGIS?

I'm looking for a big help to accomplish the following task: I have this street network of the center of Turin (IT), composed by lines representing streets, and black points representing ...
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0answers
44 views

SQL Server : find Intersecting geometries with a geometry using sql query

I asked this question on parallel site (h++p://stackoverflow.com)and think this is a better place to ask such questions I want to find all geometries in a table that intersects with spacial geometry ...
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0answers
91 views

Alternative way to find intersection between two polygon feature classes

I have been working on making a script to find intersection between two polygon ArcGIS feature classes. I can successfully do this in arcpy instances using spatial join or using search cursors on the ...
0
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1answer
25 views

how do you erase polygons that don't have a line intersection?

I am trying to erase any polygons that do not have a line intersection through them and am unsure of what tool to use using ArcMap 10.1
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1answer
38 views

What is a OGRGeometryShadow and why can't I use it in Intersects()-method?

I'm trying to script something with Python and GDAL/OGR and Shapely. What I have: two LineString geometries: "geom1" and "geom2" I made an Intersection: "intersection = geom1.Intersection(geom2)" ...
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1answer
69 views

Computing intersections for each geometry in a table

I have a table with many Linestrings and for each of these Linestrings I need to figure out which other Linestrings, from the same table, intersect with it. If I recall correctly this gives me a ...
0
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1answer
100 views

Intersecting great circle arcs and polygons

I am trying to find the point of intersection between a great cirle arc and a polygon. I am working in long/lat, where I am given the endpoints of the great circle arc, A and B, and the vertices, C, ...
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1answer
57 views

Intersect/union two different polygon layers to produce a third polygon type

Can anyone instruct me on the correct way to union/intersect two different layers containing polygons so that a third layer is created containing the attributes of the non-overlapping regions from ...
2
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2answers
56 views

QGIS failing to complete clip or intersect

I have been trying to perform a intersect (then tried using clip) on a rather large dataset on QGIS. I have been able to complete similar geoprocessing using slightly smaller datasets and the layer. ...
4
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1answer
272 views

Clip polygon and retain data

I have these two polygons: library(sp); library(rgeos); library(maptools) coords1 <- matrix(c(-1.841960, -1.823464, -1.838623, -1.841960, 55.663696, 55.659178, 55.650841, ...
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3answers
4k views

QGis: Merge intersecting polygons into one which are part of the same feature

I'm not a GIS professional so I hope I use the correct wording, at least I hope you understand my question. Let's say there are 5 polygons in the feature A. In the shape file there are more ...
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0answers
15 views

Run intersects function in PHP?

I have an old script that used to connect to a postGIS DB and basically perform: $sql="select * from mobile.regions_ne where intersects(geom_wgs84,GeomFromEWKT('SRID=4326;POINT (".$lng." ".$lat." ...
2
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1answer
281 views

Creating buffers that will not overlap in QGIS

I am dealing with a .shp with a number of points in it. The distances between points range from ~300m to 5km. I wish to create a 1 km buffer around each point with as little overlap as possible. Each ...
0
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1answer
82 views

How to use Intersect tool in ArcObjects

I'm trying to use the Intersect tool in ArcObjects SDK Java with two feature classes. Here is my code: public void intersectTwoFeatureClasses(Object in1, Object in2, Object out) throws ...
3
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1answer
129 views

How to create a cluster of crashes?

I have a shapefile with 52K points of road accidents, between 2007 and 2012. Each accident has a severity index. I want show clusters of 5 accidents (at least), for each year, that have a severity ...
3
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0answers
72 views

Most efficient way to intersect overlapping polylines

I have 4 multipart polyline shapefiles (download a sample dataset here). The geometries are identical, except for the length of segments in each shapefile. They represent 4 variables describing an ...
2
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2answers
291 views

Intersect Shapefiles using Shapely

What I'd like to try and do is intersect some point buffers with census tracts, maintain their ID's and the tracts attributes. I found a sample from ...
3
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1answer
105 views

Calculating length of road network within a polygon [duplicate]

I have a road network stored in a gdb and some polygons in another gdb. I want to populate an attribute for each polygon with the total length (in km) of the road network that it overlaps. Any idea ...