Questions tagged [intersection]

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

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Trying to fetch feature data by intersecting Vector Polygon and WMS feature layer

I am trying to intersect a user defined polygon with a Point WMS Feature Layer. I am using the following code action = new GeoExt.Action({ text: "draw poly", control: new OpenLayers....
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2answers
804 views

No intersection found between polygons I know intersect!

I'm using two geographies: one is made up of small areas (about 2200), the other large areas (about 70). Both cover all of Australia, and the small areas are not necessarily nested inside large areas. ...
3
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1answer
293 views

How to get all intersecting points to a given area and vice-versa in PostGIS?

I'm developing a project using PostGIS to hold spatial data where I have records that hold geometry point data and records that hold geometry area data. To solve my problem I'm looking for two queries ...
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0answers
280 views

How could I make this PostGIS query run faster?

SELECT st_band(rast, 1), st_width(rast), st_height(rast), st_bandpixeltype(rast, 1), st_bandnodatavalue(rast, 1), st_scalex(rast), st_scaley(rast), st_upperleftx(rast), st_upperlefty(rast) FROM public....
3
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1answer
923 views

select polyline intersections from one shapefile using QGIS

I'd like to find out if there is a way to select all of the polyline intersections within one shapefile. The lines are a road network. I've looked through the posts, and the only tip I can find is the ...
2
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1answer
91 views

What is an extension error?

I am getting an extension error when I try and intersect some points and polygons. Here is a photo of what I am trying to intersect: Any help is appreciated.
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1answer
312 views

How to identify Polygon within another Polygon layer

I have two polygons files. The first one has several smaller polygons within it eg.a shapefile with all US states, the other polygon file has a single polygon eg. a river basin. I am trying to get all ...
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0answers
308 views

error in gp.execute intersect

i generate a tool to return values using area of polygons. but when i execute the tool, visual studio show an error :"Error HRESULT E_FAIL has been returned from a call to a COM component" in gp....
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1answer
2k views

GDAL: Raster Intersection

I have two raster layers. (A) is state-sized, 30m. (B) is county-sized, 3m. I'd like to get a new raster (C) which is the part of (A) which coincides with (B), preferably scaled to the same ...
3
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1answer
463 views

Intersect multilinestring (A) with multilinestring (B) retaining linear sequencing in resultset? [closed]

I have a PostGIS table testtin2 which is a sort of pseudo TIN consisting of a single multilinestring geometry, which I am intersecting with another table align, also a multilinestring, to generate a ...
4
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1answer
504 views

automating forest cover calculations with Python

I have a layer of forest cover comprising ~ 30,000 individual forest patches, and I need to calculate the amount of forest cover within a 5 km buffer of each patch. The buffers all overlap each other, ...
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2answers
682 views

count features in polygon shapefile A that fall within each feature of polygon shapefile B

I have two polygon shapefiles, each of which contain multiple (possibly overlapping) polygons. Is there some way, using GRASS, to calculate the number of polygons belonging to shapefile A that fall ...
5
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2answers
811 views

Best strategy for polygon search?

I have a fairly simple question. What is the best strategy to do the following scenario? I think this is a very common scenario: I have a several thousands of dataset with polygon/points. Each ...
2
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1answer
378 views

Query for segments at same place and time in PostGIS

A newbie-question: I've imported the segments of several GPX-Tracks in a PostGIS-Table. Now I'm looking for a query that returns all segments that: are spatially overlapping (within a specific ...
2
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1answer
1k views

Batch intersect from a text file using Python (ArcGIS)

I am attempting to modify my code below which reads from a text file of shapefiles and executes an intersect and outputs them to a user specified location: import arcpy, sys, os from arcpy import env ...
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2answers
2k views

is there a way to tell if two linestrings “really” intersect in JTS or GEOS

In JTS (or GEOS) you can't tell if two linestrings really cross each other. The result is exactly the same whether the lines simply have a point in common but don't cross or if they really cross. Is ...
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1answer
1k views

Testing if shapefiles intersect from a list using intersect: ArcGIS

I am new to programming and scripting in general, so please bear with me. I have generated a list of the location of all the shapefiles for my workplace. The files are all placed in folders, no ...
6
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1answer
3k views

PostGIS geometry intersection test results different for Point and Linestring

Can anyone please tell me what I'm doing wrong, and how do I avoid the problem? I'll attempt to clarify what I'm doing as things go along. The geom column is a multipolygon column, all values are ...
3
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0answers
340 views

How to get all intersections between two simple polygons in O(n+k)? [closed]

Can someone help with a following problem: report all intersections between two simple polygons in O(n+k) where n - is a total number of polygon edges and k - is number of intersections. As a result - ...
4
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1answer
894 views

Is there a commandline tool for intersecting Shapefiles?

in QGIS vectorlayers can be intersected. That is apparently done by ftools and seems to be integrated into the QGIS-program itself. That is different from many other functions that call GDAL-tools. ...
2
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1answer
596 views

ArcObjects 9.2 SDK: How to intersect two SelectionSets (in-memory pointers) and return a FeatureClass?

[Update] Since posting this question, I've come to the conclusion I'm not fighting flaws in the BasicGeoprocessor object, but more likely having issues with poor object lifecycle management on my ...
3
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1answer
395 views

ArcMap: extracting overlapped buffers

I have a set of points in ArcMap which I create a buffer for each point. Then I use intersect to extract the overlapping buffers. The result is something like this: The lighter color are the ...
4
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2answers
2k views

Selecting points not snapped

I have a point layer and a polyline layer. I want to select all points in the point layer that are not snapped to a vertex in the polyline layer. How can I accomplish this? I'm using MapInfo and ...
2
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1answer
109 views

Can I take an intersection for polygons WITH A COMMON ID?

I have a thiessan polygons for a bunch of cell towers, and need to cut them when they extend more than 12 miles from a cell tower. What I was thinking of doing is taking a buffer from each point, and ...
5
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1answer
546 views

Intersect between Surface and Ray

I am interested in finding the intersection of a Ray and a Surface in ArcObjects. I already know of two solutions. First solution is to use the Locate method of ISurface: Dim intersectionPoint As ...
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2answers
2k views

How do I find the points of intersection between a small circle and a great circle?

I only actually need to intersect a great circle arc i.e. the shortest path between two points, with a given small circle. I found this tutorial for intersecting two great circle arcs, but ...
5
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1answer
665 views

Intermediate points on a small circle

I need to interpolate lat/lon points along a small circle, with a given centre and radius. I've successfully used these formulas for great circles. What is the equivalent for small circles?
4
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3answers
711 views

Is the Intersection Operation Commutative?

In map overlay, is intersection of map layers a commutative operation ie layer_A intersection layer_B = layer_B intersection layer_A? If layer A is a square and layer B is a triangle. In this case, (A ...
9
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1answer
2k views

Intersection of multiple layers in PostGIS

I need to write PL/pgSQL stored procedure for calculation of intersection of multiple layers. For example, for three layers A, B, C this function should return ABC geometry: Function takes as input ...
5
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1answer
2k views

How do I find the intersections of 2 circles on earths surface?

I have the circles' center in lat & long, as well as the radius in meters. How do I find the circles intersections? Edit: EXAMPLE: Circle 1: Center on Earth's surface (43.564627,-116.220524) ...
6
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1answer
4k views

How to get the intersecting polygon of two polygons? (using JSTS intersection)

I want to intersect two polygons within an OpenLayers layer. I found the JSTS library, which should be able to intersect two polygons, and return the new created polygon of the intersection. The ...
3
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1answer
994 views

Search Intersections with ArcGIS Server 10 without using Address Locator

Is there a way to search for intersections on a centerline layer in ArcGIS Server 10 without using an Address Locator? I can send direct queries to the centerline layer for individual road segments. ...
36
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4answers
11k views

Separate polygons based on intersection using PostGIS

I have a PostGIS table of polygons where some intersect with one another. This is what I'm trying to do: For a given polygon selected by id, give me all of the polygons that intersect. Basically, ...