Where features overlap

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3
votes
1answer
60 views

Strange behavior of of ST_Intersects in PostGIS

I'm quite new to GIS and PostGIS and, probably, this question has been already answered multiple times, but unfortunately I was not able to find an answer. I have few polygons and I want to find ...
1
vote
0answers
15 views

PostGIS Street Intersection Autocomplete with full text search

What I'm attempting to do is create a custom autocomplete for addresses, road intersections, POI's, etc. For now we are going to using Mapbox GL (we'll be creating a custom map at a later phase), ...
1
vote
1answer
39 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
votes
0answers
33 views

QgsSpatialIndex partial or complete overlap

I'm working on adding some functonality to a QGIS plugin. It currently uses a QgsSpatialIndex to efficiently compute whether the features of a vector layer intersect (potentially millions) of ...
1
vote
0answers
26 views

How to collect values from iterated intersections, in ModelBuilder

I have a points feature class which I am intersecting with a number of polygon feature classes, one at a time (i.e. points AND polygons1, points AND polygons2, etc...). Each time I do an ...
4
votes
1answer
70 views

Find all intersections of a LineString and a Polygon and the order in which it intersects it

I would like to find out all intersections of a LineString (River) through Polygons (Municipalities). I would like to list the order of municipalities which the river crosses, using linear ...
0
votes
0answers
12 views

Intersect Iso_rectangle_2 with Polygon_2 where Polygon_2 uses Projection_traits_xy_3

I have a set of [Point_3][2] that constitute a Polygon_2 using the Projection_traits_xy_3 typedef CGAL::Exact_predicates_inexact_constructions_kernel K; typedef CGAL::Projection_traits_xy_3<K> ...
1
vote
0answers
45 views

Calculating area of intersection of polygon to another layer in ArcGIS for Desktop?

I am very new to GIS, especially ArcGIS. I am currently using ArcGIS 10.2, and I have 2 layer, namely the purple feature map(this layer is an import from arcgis online, it doesn't seems to be an ...
3
votes
1answer
41 views

ArcGIS find all polygons that intersect with more that one polygon from another layer

I have two layers with polygons. I want to find those polygons from first layer that intersect with more that 1 polygon from second layer and find those intersected polygons ID numbers: 1 from first ...
1
vote
0answers
15 views

Subset of spatial data causes slow SQL Spatial STIntersects

I've been having an issue were a specific subset of data causes an SQL spatial intersect to run extremely slowly. I am running sets of 1000 points against a subset of polygon layer to be intersected. ...
4
votes
0answers
41 views

Why won't my points (that I created by intersection) won't 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, ...
2
votes
0answers
24 views

Intersect, Spatial Join?: One Line crossing Multiple Polygons, assigned wrong attribute

I am looking for any possible solutions to a problem I am encountering with ArcGIS. I am using census block groups (CBG) to assign streets an income level value based on their location within the ...
1
vote
1answer
73 views

Problem intersecting shapefiles with OGR in Python

I'm trying to move from ArcPy for geoprocessing. After searching some posts, I found this solution using the GDAL/OGR Python bindings: Intersect Shapefiles using Shapely My code is the following: ...
3
votes
1answer
44 views

Rotate symbols perpendicular to line angle (QGIS)

I have lines representing curving streams and want to angle symbols at various points on the streams so that they are perpendicular to the angle in their particular locations. What QGIS seems to do ...
0
votes
0answers
14 views

How to Find Source and target using STBuffer And STIntersects in SQL Server?

I am using this query to find the source and target from Routes table, but it's not getting the correct result SELECT TOP 1 a.target FROM Routes a WHERE ...
1
vote
1answer
25 views

Tabular Intersection producing Empty Output Why?

I am trying to run a Tabular Intersection on ArcGIS 10.2.2 between a 1000m buffer and a forest layer to establish the percentage cover and total area of trees within the buffer areas. Everytime I run ...
4
votes
2answers
60 views

What is the correct syntax for the geometry object's “intersect” method in ArcPy?

I'm building a script that utilizes the intersect method of the geometry class so that I can run an intersect analysis on individual polygons within a feature class. As stated here, "intersect ...
1
vote
0answers
25 views

python 2 polygon intersection

I have slope values derived from a DEM which I reclassified into NoDATA and vaules which I need. Then I made a polygon from this raster. I need to do intersection or something like that with the ...
0
votes
1answer
30 views

Intersect elevation interpolated from CAD file in ArcGIS

I have two datasets - contours and vector (water, roads,...) Vector layers were used as breaklines to generate the contours. Then the contours were generalized a bit. For quality check I need to ...
0
votes
0answers
20 views

Using modelbuilder to calculate different areas of overlap over time?

Been looking all over the place for a solution to this and nothing’s turned up, so I thought I’d ask directly. I am looking to build a model that calculates the total area of timber harvest within ...
0
votes
0answers
40 views

Intersect using Open Source GIS [duplicate]

I have a CSV containing user locations (has lat, long, userid, timestamp). I have a countries shapefile (has country name, geometry - got this from thematicmapping.org). I am trying to append a ...
0
votes
3answers
95 views

Iterating Intersect_analysis over polygon shapefile using ArcPy?

I am using ArcGIS 10.3.1 for Desktop and I have two shapefiles: A set of stream (vector line) data A fishnet of polygons I want to know, for each polygon in that fishnet, what the total length of ...
1
vote
3answers
58 views

Intersection of 2 Linestrings (not interpolated)

I am struggling with a query in POSTGIS I want to find linestring geometries where the geometries are containing the same point. I don't want to calculate the intersection points. I only want to ...
1
vote
0answers
37 views

Using Python Opensource Libraries to check users who visited a store [closed]

I have a few files with location information: 1) User Lat Long Pings in Parquet Files (can be converted to CSV) format - this contains userid, timestamp, lat and lon 2) US County/State Shapefile 3) ...
2
votes
1answer
41 views

QGIS and intersections

I have MultiLineString geometry data from an ESRI shapefile. I also have a polygon (region) that I have created in QGIS using the drawing tools. When I attempt to find the intersection between the ...
1
vote
0answers
45 views

Why does QGIS only intersect one part of the layer?

I have a QGIS layer with information about administrative boundaries at sub-municipality level. I want to extract only land area in each sub-municipality using information from another layer. I've ...
1
vote
1answer
70 views

How to select overlapping/non-overlapping polygons from a single shapfile in QGIS?

I have a shapefile with a series of polygons, some of which intersect each other and some that don't. I want to select only those that do not overlap with any other polygon. I've tried the Select by ...
0
votes
0answers
29 views

Detecting features intersecting with Profile Line using ArcGIS for Desktop?

I am using ArcGIS' (10.2) 'Intersect Line' > 'Create Profile Graph' functions (3D Analyst Toolbar) to get cross sections of lines from a DEM raster. Does anyone know, if there is a similiar ...
5
votes
3answers
225 views

How to fix thousands of small overlapping polygons?

I'm using ArcMap 10.3. I have a layer of different land use types. I found out that many polygons overlap each other and as a result the same polygon have two different land use types. Thanks to ...
1
vote
0answers
37 views

How to test polar stereographic projection for a specific longitude intersection?

I'm writing a library that tests grids defined by map projections for intersections, and am running into an issue implementing the test for polar stereographic and rectangular projections - ...
1
vote
2answers
50 views

Clipping a SpatialPoygonsDataFrame to another SpatialPolygonsDataFrame

How do I restrict a SpatialPolygonsDataFrame so that none of the polygons lie outside of an "underlying" SpatialPolygonsDataFrame? The application I have in mind involves Voronoi Polygons a la Carson ...
1
vote
2answers
71 views

Where is the drawn feature when the drawend is triggered in OL3

I have written a piece of code to check if the drawn line is intersecting other lines in the vector layer. If so, then the line should be split and new lines should be added to the layer. here is my ...
1
vote
2answers
38 views

How to set independent path in QgsOverlayAnalyzer >> intersection statement using Python?

How to set independent path in QgsOverlayAnalyzer >> intersection statement using Python? QgsOverlayAnalyzer.intersection(QgsVectorLayer, QgsVectorLayer, QString, bool onlySelectedFeatures=False, ...
1
vote
0answers
27 views

pgr_nodeNetwork doesn't place new nodes properly

I wanted to use pgr_nodeNetwork tool to split lines where there's no vertex on intersection. The tool doesn't seem to work as expected, though. It doesn't place new nodes right where the two lines ...
1
vote
2answers
64 views

OL3 GeoJSON vs. turf GeoJSON

I am using OL3 and I try to inspect whether two lines are intersecting or not using turf. I used GeoJSON in OL3 and fed the lines into the intersect() in turf but I get Unknown GeoJSON type. here is ...
0
votes
1answer
28 views

Is it possible to intersect categories within shapefile using ArcGIS for Desktop?

I have a shapefile composed of fire scar polygons identifiable as unique categories based on year of fire. I am interested in measuring the area of overlapping fire scars from different years. Is ...
6
votes
2answers
273 views

Clipping vs Intersecting

I was curious why clipping shapefiles was just so difficult and whether it was different to intersecting shapefiles? You will see from one my questions that I gave up trying to clip a polyline with a ...
1
vote
1answer
39 views

Autofill format with atlas

I am trying to create an autofill format on QGIS, based on an atlas. There will be some dynamic text fields and some boxes which should be checked with an "x" in case the atlas geometry intersects a ...
3
votes
2answers
81 views

PostGIS does not find intersection between line and polygon

I have a line and polygon: I would like to programmatically figure out whether they intersect or not. So, I do: select ST_Intersects ( ( select ...
5
votes
2answers
170 views

How to extract value from a raster based on lat and lon?

I have several netcdf files that I can read using the netCDF4 library in python. The data is gridded in 4320 rows and 2160 columns. I also have a list of lat/lon (in decimal degrees) and I am trying ...
4
votes
1answer
60 views

PostGIS > Intersect two circles. Each Circle must be built from Long/Lat degrees plus radius

I'm trying to figure this out, so I wanted to try asking to the experts. This question is related to PostGIS (from postgresql). What I want is: 1) Based on a longitude and latitude I want project ...
0
votes
2answers
147 views

Python buffer points and clip with line-segment (OS Open Roads in BNG) [duplicate]

I have an array of points (in latitude, longitude coordinates) which I would like to buffer and dissolve (into a polygon) and then intersect the Ordnance Survey Open Roads (projected in BNG) with that ...
0
votes
0answers
33 views

Use ArcMap to determine Polyline overlap, at a certain tolerance, against multiple other Polylines

My goal: Take one fiber route and see how much of the route is within a given distance from 0 other routes, a single route, two routes, and three or more routes. I have used the intersect function to ...
7
votes
2answers
65 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
0answers
42 views

Intersect does not fully process [closed]

Goal: Use python script to find overlap between various shapefiles in folders Inputs: folder 1 with multiple shapefiles and folder two with multiple shapefiles Method: #First intersection ...
2
votes
3answers
94 views

Efficiency in PostGIS: objects near point- ST_Intersects around buffer Vs ST_DWithin

I need to find all buildings in radius of 25m from given location. I thought about 2 PostGis quires that can handle this, when I run it they both give same time execution. But I want to know which one ...
1
vote
1answer
57 views

Create common vertex where line was snapped to another using “snap to segment”

I have a schematic diagram within QGIS consisting of a single layer of line segments. Lines have been snapped to others using "snap to segment". When using the snap to segment option the two lines ...
2
votes
2answers
161 views

QGIS 2.10.1 Clipping Algorithm Results In Empty Layer

I apologize for the redundancy of this issue, but I have explored all the information I could find over the past couple days and have yet to find a solution to what seems to be a very simple task. I ...
2
votes
1answer
35 views

QGIS: How to scale attributes when clipping / intersecting

I'm working on a project involving a ratio of frequent travellers / population divided in Forward Sortation Areas from Canada Post (FSAs are the first three characters of a postal code: A1A). I ...
0
votes
0answers
24 views

Enclosing building models from bottom (Missing GroundFeatures) using FME?

I have 3D building model of the city and I would like to export it to proper CityGML model. I am trying to find out, how to make an intersection of building and terrain in order to make ...