Where features overlap

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2
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1answer
237 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 ...
2
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0answers
12 views

Intersection of a vector linestring and underlying DEM

Following is an screen-shot where ASTER DEM raster layer has been overlaid by a road linestring vector layer. I want to extract those DEM pixels which are lying exactly beneath the linestrings. I want ...
5
votes
1answer
365 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 ...
2
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2answers
113 views

Sextante modeler feature selection

I am trying to select grids (polygon geometry) that intersect with a building layer. I can do it by using "Select by location" tool and then I generate centroids from the selected grids. There is no ...
1
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1answer
34 views

How to find points present in one layer but not in a second layer, using ArcGIS?

I have two layers, A and B, with B consisting of a proper subset of the points in A. How can I produce a third layer, C, consisting of just those points found in A but not in B. In R, I would just ...
3
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1answer
108 views

Calculate population coverage?

I am relatively new to QGIS and hope I explain this right. I am looking at the percentage of an population that has geographical access to healthcare. Therefore I have one shapefile with village ...
1
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1answer
24 views

How to calculate the intersection between WFS layer and a PostGIS table

I need to calculate the intersections betweek a WFS layer and the geometries stored in PostGIS table. Then I should save the geometries of the intersections in a separate PostGIS table. Do you have ...
0
votes
1answer
172 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 ...
2
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3answers
924 views

Intersect (analysis) of polygons generating empty output

I have previously asked a question on determining the area of polygons with another polygon boundary. Determining the area of each polygon within a polygon boundary? I came to the conculsion that ...
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1answer
18 views

arcmap mapping information of 2 layers, how to get rid of non-related results

I have 2 layers on the map: 1 drain line layer and 1 segment layer. The segment layer is covered by the drain line layer. Now I want to get the corresponding attribute values on drainline layer which ...
0
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1answer
52 views

Intersecting Overlapping Polygons Individually in ArcGIS

Map Layers: -Census Tract Shape File w/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 ...
2
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2answers
152 views

Separate a polygon in different polygons depending of the distance to another polygon

I have a reference polygon "R", and others polygons (in grey). I want to separate each grey polygon in multiple polygons, depending on the distance to R with different Buffers : - The red line is R ...
3
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1answer
73 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 ...
1
vote
1answer
21 views

Intersection of triangle and polygon

I have a triangle and an arbitrary polygon lying on the same plane in 3D space. I need to find the fastest way to determine if these two intersect, one is inside the other, or completely separated. At ...
5
votes
1answer
491 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 ...
0
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1answer
266 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 ...
1
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1answer
65 views

How to get Intersection point from two lines (coordinates)

I have tried for ages to find the algorithm for getting the coordinate of two intersecting lines from a given coordinate (latlong). As the picture below suggest. I have two coordinates (A and B). ...
3
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0answers
74 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: ...
1
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1answer
89 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 ...
2
votes
1answer
54 views

QGIS Intersection problem

The QGIS Intersection tool is not working for two shapefiles in Version 2.2 or 2.4 (haven't tried earlier versions). I get a new shapefile with all the attributes, but no features. However, when I use ...
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0answers
24 views

Data Transfer of a point on line using the anchor point

Can I a line feature, the anchor point touches a point feature transferred the field value, even when the point touches another line(s)? How does this work?
3
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0answers
50 views

Performing buffering and intersection with script in PyQGIS

I wrote a script that performs the intersection of two layers: The first Layer -> layer1, represents the rivers The second Layer -> layer2, represents a set of circular dots distributed in a ...
2
votes
0answers
80 views

Create circles around a point on a map measuring the radius in hours

Disclaimer: I am not experienced in GIS and hope this question fits in this category. I was wondering whether it is somehow possible to create a circle* around a city, using Google Maps or the like, ...
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0answers
48 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 ...
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1answer
32 views

MapInfo incorrectly counting lines intersecting a buffer

I made a buffer for all objects on start and end nodes of polylines then disaggregated them. I then used update table to derive the number of lines intersecting: However this appears to be ...
0
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1answer
21 views

Clip polygon features with country boundary ArcGIS Desktop

I am trying to trim the edges of some polygons based on a country boundary. I have tried both clip and intersect, but neither seem to be doing what I want. Below is the image I am working with. When I ...
3
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2answers
129 views

Find intercept WGS84 coordinates between two segments defined by (Lat1-Long1 and Lat2-Long2) and (Lat3-Long3 and Lat4-Long4)

I need to determine the WGS84 coordinates for a point that is defined by the interception of two segments represented by two sets of WGS84 coordinates each (lat1-long1, lat2-long2) and (lat3-long3, ...
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0answers
30 views

Iterating Intersect Between Dates for single and dual shapefiles of multiple polygons

I'm looking at day range overlap for an animal - to do this I'm looking to generate intersection polygons from the animal's range on day 1 to day 2, then day 2 to day 3 etc., from day 1 to the end of ...
2
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0answers
29 views

Showing Linestring from SQL statement with CartoDB

I have cartodb sql statement to return what polygons are intersected by a linestring, but I'd like to have the linestring visualized over the polygons on the results. Also not add the linestring to ...
2
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0answers
24 views

Distribute Hotel Beds According to Population Density in Buffers using ArcGIS for Desktop?

I am running an ArcGIS for Desktop analysis where I am plotting competing hotel facilities and then distributing their beds in a 5-mile buffer around the site. I would like to distribute the beds ...
1
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1answer
86 views

Automating Intersect between two polygon layers

I have a spreadsheet that has county-level occurrences of around 1000 species within the US in the column headings (Species State County). Thus, for some counties there may be multiple species. I ...
0
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1answer
36 views

python code to create an intersection loop with a geodatabase [closed]

I am trying create a loop that will intersect each individual township with a statewide section layer. I am having trouble with the syntax of the intersect tool I think, but maybe it is something ...
0
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2answers
2k 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 ...
2
votes
1answer
76 views

How to do a “fuzzy” intersection?

I have two layers that look like this: I want the intersection (or whatever the correct term may be) to look like this where the output polygons are the same as the original base layer, just with ...
1
vote
3answers
46 views

Model Builder is not intersecting erased and selected files

I'm having trouble debugging my model that I'm creating in ArcMap 10.1 ModelBuilder. The model is just a simple string of geoprocesses, but there's a point at which the model isn't exporting the ...
1
vote
1answer
55 views

Closest point on a line segment from point outside the line

From the above pic I found the value x from line (p1,p2) and point a. Using y=mx+b and an imaginary red line which is perpendicular to the black line having slope -1/m and the intersecting point ...
3
votes
1answer
412 views

Intersection of drawn polygon with WMS layer features. Better of two methods?

Scenario: Several WMS layers with polygon features. Objective: Draw a polygon with OpenLayers and allow it only if doesn't not cut any features in WMS layer. It can contain the features as a whole ...
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0answers
20 views

Basic Intersect in mysql

I've looked all over but can't find a simple snippet of mysql spatial intersect. Does mysql support it? Does anyone have a working exmaple? Thanks
1
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1answer
98 views

Iterating over all features in featureclass to intersect them individually with polygon using ArcPy?

I've got a point featureclass, and I'm trying to individually intersect each feature with a polygon featureclass to get some information about which polygon each feature is in. I did one intersect ...
2
votes
1answer
105 views

Calculating countries flown over on flight path

Say I have two airports given. I can then get their coordinates. Now that I have the beginning and end coordinates I can draw flight-path from the two locations. Now my question is that given two ...
0
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1answer
55 views

How do i rescale feature classes of different scales for intersect analysis?

before I intersect 2 feature classes of different scales (e.g. 1:200,000 soil map and 1:25,000 land use map), should I rescale them like how u would resample raster datasets to the same resolution ...
1
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3answers
124 views

How to count points once with overlappying polygons?

All, We're using parcel data (polygon) to count student locations (point) based on parcel type. We're doing this using SQL and the ST_Intersects function. It works great, except the City and County ...
1
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0answers
120 views

PostGIS: How to distinguish overlapping routes (i.e., LineStrings) based on their direction?

I have a set of routes which are represented by LineStrings in my PostGIS database. These routes represent journeys that people make. I want to come up with routes that (a) overlap, and (b) have the ...
0
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1answer
65 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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2answers
93 views

Is it best to use multipolygon or polygon features for large intersect operations?

I have two large layers that I want to do intersect operations. One is municipalities and the other is landuse. Right now, the landuse layer is of MultiPolygon type that is, for the entire state, I ...
0
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1answer
32 views

Get attributes from intersecting lines to label generated intersection point

I have an urban road network (as a feature class), consisting of only polylines. I have to make a database of all the intersections between the streets. The problem is that as I generate those ...
0
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1answer
66 views

postgis finding lines that touch and update

I am not much of a postgis guy so please bear with me. I have a subset of lines representing exits and roads around those exists. Main roads and exists can be distinguished by their class attribute ...
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0answers
40 views

How to overlay polygons that are in the same layer

I need to INTERSECT many polygons that are in the same layer. Actually each polygons from my layer represent an area of influence from one specific bird species. Since I used to use ArcMap, I found ...
3
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2answers
328 views

Postgis: aggregate function for intersection

I have a PostGIS Table with LINESTRINGS. I like to a query that returns all Roads that are connected. So I get a set of unconnected trees (in german 'Wald (Graphentheorie)') pseudo code: select ...
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0answers
43 views

Determine the list of circles (from 100K circles), that overlap with a given polygon

This question was asked on StackOverflow, came here because no response has been posted so far. Existing data structure we have polygons represented as an ordered list of lat/long coordinates and ...