Where features overlap

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3
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94 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 ...
3
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0answers
77 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 ...
3
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0answers
98 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: ...
3
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0answers
140 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 ...
3
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0answers
203 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 ...
2
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0answers
201 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, ...
2
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0answers
35 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 ...
2
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0answers
223 views

How to best intersect vector data with raster data?

I have Open Street Map [OSM] data imported so that I can access the geometry of buildings. I have also loaded SRTM digital height data from NASA from a GeoTIFF raster. I have projected the raster into ...
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96 views

How to copy the contents of an attribute from one vector layer to another one that touches it or intersects it?

I have 2 layers that intersect, called layer A and layer B. Layer A has an attribute (X) that I want to copy wholesale (for the whole layer) to layer B, so that when object A1 intersects object B1, ...
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300 views

3D features (Polyline, Polygon) intersection library

For my research I am looking for a (python) library to get the intersection of some 3D features. The features can be Polygons or Polylines. Mostly I need to intersect a plane with my features and get ...
2
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0answers
188 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 ...
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591 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
1
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0answers
23 views

Incomplete results from an intersection

I am trying to map the density of buildings in flood-prone areas. In order to do that, I created a grid of equal-sized squares. I want to intersect the layer of buildings with the grid so I can ...
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0answers
21 views

Select features intersecting a linestring in QGIS

I wrote a python plugin that grabs all (vector, linestring) features between two points on the map. At the moment, I select all features intersecting the rectangle around these two points, and then ...
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0answers
9 views

Finding polygon from two arcs using CLI tools or some library

I'm trying to convert from textual representation into a set of arcs and lines. The 'input' I have is: The area is within lines joining two semicircles with a radius of 0.67 NM centred on: 641139N ...
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44 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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0answers
51 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
43 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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22 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." ...
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29 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?
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0answers
27 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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174 views

How to simplify a self intersected / self overlapped polyline using ArcObjects?

I have a self intersected polyline, how can I break it into 5 records stored in the same table using arcobjects? (splited by vertices and the intersection point) Here is what I have got and it ...
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166 views

Using M 'Measure' value in SQL Server 2008

MS Sql Server 2008 geometry type supports adding Z and M values to geometry objects, including linestrings. However, I cannot find any way to make use of these values, since methods such as ...
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0answers
90 views

How to Simulate Venn Diagram of Buffers using QGIS?

For the sake of simplicity, suppose I have only 2 points on one layer. Point A have population of 100, and point B have population of 150. I do find buffer of these 2 points and it is intersect. I ...
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190 views

Intersection between a ray from lat, lon, alt, with pan, tilt and earth's surface

I have a problem that consists of finding the intersection point between a ray from a given lat, lon, alt, that is looking to a given pan and tilt angles and the earth's surface. I need the lat, lon ...
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84 views

How to get intersected points between polygon and line in desired order

I have polygon for example "POLYGON((5 1, 6 1, 6 5, 5 5, 5 1))" that I want to intersect with line "LINESTRING(0 2, 10 2, 10 3, 0 3, 0 4, 10 4)" and get intersection points in the order that they ...
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71 views

Trouble intersecting a polyline and contours (Hack index / stream length gradient index)

Working on creating polylines for measurement using SL index (hack index). So far I have the main trunk of a stream, and contours at 10m. What I am trying to do is a) get the elevation at each ...
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0answers
54 views

Broadband coverage GIF image layer needs to be selectable (ArcGIS)

I am working on a project on Arcmap where I have 80,000 co-ordinates of postcodes and a broadband coverage map. I need to know which of the co-ordinates intersect with the coverage map. I have added ...
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0answers
104 views

how to avoid Intersection of polygons via python code

i am using QGIS 1.8 and i can set the check box in Setting\Snapping Options "Snapping and Digitizing " dialog to avoid polygon intersections and enable topological editing but i am looking for a way ...
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0answers
108 views

Gdal/Ogr - OGRLayer.Intersection() Question

I was trying to perform intersection on two feature classes (shape file format) using OGRLayer.Intersection(), but have problems making it work with C# bindings. I am not able to figure out on how to ...
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0answers
335 views

intersect two shape files using QGIS API

I am trying to automate a process of a shape file. We are using google maps engine and we have limitation on number vertices in a shape file. so I am using a grid to split the shape files. In GUI , I ...
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0answers
32 views

Suggestions for vector format for polygons

I am using two polygon tables in postgis (A and B ). I need to make a vector file that incorporates information of the overlapped polygons B intersecting each polygon on (A). I can make a single ...
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307 views

How to handle/ avoid intersect errors when clipping the difference between two layers?

Using QGIS + Grass, I've added a shapefile of coastline and islands to my map. I then buffer this shapefile to create a coastal zone of a known width. At this stage the buffer consists of the ...
1
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0answers
275 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 ...
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0answers
104 views

Copied points not intersecting the original points

I'm using an arcpy search cursor to access a Oracle database. I have a simple Python class that I copy the returned row objects into, which gives me more flexiblity than the cursor. The problem is ...
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19 views

Efficient way of determining polygon intersection with bounding box

I have a set of polygons, and I need to check whether they are intersecting with a given bounding box(rectangle). What I am doing is, I am taking every vertex of polygon and checking whether it's ...
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0answers
36 views

Intersection of two lines from points with direction angles

Given two points and direction angles from each point to a third point, but no distances, how do we get the x,y coordinates of the third point? In other words, how to find the intersection point where ...
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0answers
31 views

Determining intersection between list of points and list of linestrings?

I'm coding in php. I have a list of point coordinates (very large one) and a list of linestring geometries (large too). I'd like to determine for each linestring, the point coordinates that ...
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0answers
55 views

how to make an intersection between a shapefile and A WMS layer in QGIS 2.8.1

I am using QGIS 2.8.1 I think what I want to do is an intersection between a shapefile and A WMS layer, both in vector format. I have 1 small vector layer that consists of different forest stands, ...
0
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0answers
25 views

How can I redistribute points within a polygon using certain criteria in ArcGIS?

I have some points (representing pharmacies) scattered around my research area and I would like to redistribute those points through the area using the following criteria: The points should ...
0
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0answers
79 views

How to find co-ordinates of two intersecting features (circle and polyline) in vb.net using arcobjects?

I am new to arcobjects and i want to find the co-ordinates of the intersection points of a circular arc and a polyline. Can somebody please help me with this. I've tried the following code but it is ...
0
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30 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 ...
0
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171 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). ...
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200 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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169 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 ...
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38 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 ...
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34 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
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62 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 ...
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86 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 ...
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119 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 property ...