Where features overlap
1
vote
3answers
33 views
Breaking a continuous contour shapefile into smaller parts?
I created this contour shapefile and I need to break it into smaller parts so its better to manage. I also have a line shapefile of where I want the breaks. Is there a way to intersect and break them? ...
0
votes
0answers
21 views
polygon/raster intersection artifacts
I'm intesecting a polygon with a raster using PostGIS > 2.0. The outer boundary of the polygon is formed by the convex hull of polygons (building outlines plus safety margin) and the inner rings are ...
1
vote
1answer
16 views
Intersection with JTS Geometry
I want to calculate an intersection between two geometries with the intersection function from JTS Geometry.
What happens, if the geometries have different SRIDs?
SimpleFeature sf1=...; //SRID ...
2
votes
2answers
45 views
Differences Between the Clip Tool and the Intersect Tool
How is the clip tool different from the intersect tool in terms of how it works or the result? I don't have a specific situation in mind. I was learning about each of these tools and was curious about ...
0
votes
0answers
22 views
GEOS: How to intersect without noding?
As discussed in this question intersecting two GEOS line geometries gives a result which has also been noded.
This is very nice if noding is what you want, but is it possible (through the C api) to ...
2
votes
3answers
98 views
How to test if geometry is inside another?
I need to tell whether geometries from a shapefile are inside other geometries or not.
For example, I want to test if there are trees (represented as points in trees.shp) inside the urban areas ...
2
votes
1answer
70 views
How to efficiently check for feature overlaps with Arcpy?
In an effort to reduce processing time, I am looking for ways to pre-process data within my script. I have ~18,000 featureclasses with ~500 features each (all simple circle polygons) from which I want ...
0
votes
1answer
46 views
Rhumb lines intersection
I looking for algorithm how to find out whether two rhumb lines given by point1 with azimuth1 and point2 with azimuth2 have intersecting point. Have anyone idea how to find intersection ?
For ...
1
vote
1answer
37 views
openlayers point intersection
For example, I have 2 points and I want to know if they intersect. If yes, I need to delete first points. Should I use OpenLayers .intersects method? Because it greatly depends on zoom level.
Or ...
3
votes
3answers
131 views
ArcObjects C#: select intersecting polylines
My questions seems trivial but it is a real blocker for me. So please help!!!
How can I, using ArcObjects with C#, select only those polylines in one layer that intersect with each other?
It sounds ...
1
vote
0answers
67 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 ...
3
votes
1answer
108 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 ...
0
votes
0answers
30 views
Slicing / Cutting a Polygon / Polygon List based on another geometry
I currently use GeoDjango (GEOS, GDAL, PROJ4), I have rather medium set of polygon data (buildings).
To streamline them to a client efficiently (client has a limited viewport) I only want to send the ...
1
vote
1answer
53 views
How to use QgsOverlayAnalyzer class in pyQGIS?
I am very new to Python scripting in QuantumGIS, so bear with me please.
I am trying to use the QgsOverlayAnalyzer class in QuantumGIS (http://www.qgis.org/api/classQgsOverlayAnalyzer.html#details) ...
0
votes
0answers
74 views
How to insert vertex in polyline layer where we have a point in a point layer
I have a polyline layer and a point layer. Some of the points are on the polylines, but the polylines do not have vertex in these points.
How can i insert vertex there ?
1
vote
1answer
149 views
Lat Long line intersecting with circle
Can anyone help me what's the algorythm to calculate points of intersection whet is given one point p1 [lat,long] , bearing x (let say 137 degrees), arc center [lat,long] and radius?
I woulde like to ...
2
votes
1answer
58 views
Remove intersect of one polygon from another in R
I am trying to remove the intersect from Poly2 onto Poly1. Below are the coords of the 2 polygons.
> coords1
[,1] [,2]
[1,] 992.0161 7462.531
[2,] 950.1962 7413.532
[3,] 902.3632 ...
2
votes
1answer
86 views
Intersection of convex polygons on a spherical surface
There are a number of algorithms available for the intersection of two convex polygons, but I am interested in an algorithm to find the intersection of two convex polygons on the surface of a sphere, ...
1
vote
0answers
26 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 ...
1
vote
2answers
51 views
Showing OpenStreetMap intersections in ArcMap
I'm trying to carry out a few tests on OpenStreetMap data to test its quality, using ArcGIS. One of the things I'd like to investigate involves checking that all road intersections are represented by ...
2
votes
1answer
147 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 ...
3
votes
1answer
132 views
PostGIS: Using a polygon to 'mask' linestrings returns both multi and linestrings
I have a table of linestrings (OSM roads, in fact) that I'm displaying on a map. I want to filter them so that only those within a certain area are displayed- I've already done this with the coastline ...
1
vote
0answers
80 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
vote
1answer
168 views
Why do I get 'KeyError: 0' when using Line Intersection tool?
I'm using Quantum GIS version 1.8.0-Lisboa and trying to create intersection point using Intersection tool. (Vector -> Analysis tools -> Line Intersections )
But when I do that for my shapefile, It ...
4
votes
2answers
109 views
Creating space at intersection of two links
I have a shapefile consisting of two links which are crossing over each other.
I want to create an empty space at the point of intersection of the two links.
As of now, I have been manually doing ...
3
votes
1answer
73 views
Help with intersections in QGIS
I have a shapefile which defines for me the area of each oil field in the North Sea (~300 fields). I also have a shapefile which defines the location of every well that has been drilled (~13000) ...
5
votes
3answers
302 views
Extract Overlapping Polygon Data to Points
I have a polygon data set of corn yield collected by a combine. However, as the combine drove through the field, there was slight overlap between passes, leading to overlapping polygons within the ...
4
votes
3answers
117 views
Trying to combine nearby points into a polygon
We have collected millions of cell phone strength readings. I am trying to group points of the same strenght that are within a distance of each other in to a polygon. I asked on the
postgis mailing ...
4
votes
2answers
314 views
How to Intersect between a vector (administrative areas) and a raster layer (slope)?
What I've got:
1: A vector-layer with administrative areas of my country
2: A raster-layer with the slope of the terrain of the same country (it is derived from SRTM elevation data with QGIS)
What ...
1
vote
1answer
202 views
Intersection between two SpatialPolygonsDataFrame using gIntersection function in R
I want to select a subset of my map (a SpatialPolygonsDataFrame) to create a new vector map = part of the initial map included inside a given polygon (eventually, inside several polygons).
I have a ...
4
votes
2answers
392 views
OpenLayers - Get features inside a polygon
In my OpenLayers map I allow users to draw an ad-hoc polygon vector. Then I need to get all the features from a WFS vector layer that fall within the ad-hoc polygon.
Here is the code I have that ...
3
votes
4answers
195 views
How can all polylines within a polygon be selected and then operated on to determine the average value from an attribute field?
I have two files illustrated wonderfully below: 1) Polyline (shown in red), 2) Polygon (shown in black).
The polyline file contains a numeric attribute (elevation in meters).
I would like to select ...
2
votes
1answer
59 views
Line feature, Merge and Dissolve
I have a layer with several polygons and a layer with line above these polygons. Its like a map and a road network on it.
I have to find out the length of line in each polygon.
I used the intersect ...
4
votes
1answer
195 views
adding multiple points to a linestring in PostGIS
Though a newbie to PostGIS, I'm having trouble solving something that I think should be farily straightforward.
I have two linestring tables, both consisting of simple, 2-node line objects: one has ...
4
votes
2answers
112 views
Keep nonintersecting polygons during clip
I am using ArcMap 10. I have two datasets, one of which consists of many small contiguous polygons, and one which has many small non-contiguous polygons. The first dataset is census blocks, and the ...
4
votes
2answers
223 views
How to select features that intersect but don't touch (using ArcObjects)?
So how do I do that? ArcMap's Select By Location selects also all features that touch, but I only need the ones that actually intersect the area.
I currently use ...
5
votes
2answers
850 views
Calculate area of intersecting polygons in QGIS
I have two collections of shapefiles:
1 - postal codes, administrative and political areas
2 - various land use categories like parks & allotments, and points like trees
I want to produce ...
4
votes
1answer
274 views
Line intersection with circle on a sphere (globe or earth)
How can I find the intersection point of a line and a circle on a sphere (on earth)
Please, if any one knows a good solution help.
Thanks in response :)
1
vote
2answers
490 views
Querying intersecting areas areas - Oracle Locator or Spatial?
My spatial database is Oracle. We are wondering if we can use basic Oracle Locator or need to get the more expensive, full, Oracle Spatial.
My application's requirements include having to be able to ...
2
votes
2answers
206 views
How to single out country data from a world data map?
Say that i have two "data sources";
A global map of average wind speeds,
A shape file (or similar information) of all country borders in the world.
How do i combine these two sources and extract ...
3
votes
0answers
126 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
votes
2answers
782 views
How to repair topology of a shapefile?
I performed an object-based image analysis using ENVI EX, and each of the classified features were exported as a shapefile. I transferred those shapefiles into ArcMap 10, and tried to intersect them ...
-2
votes
1answer
174 views
Postgis error on select all intersetcs of a polygon [closed]
i can get all polygon on intersects this:-7.9245860488441 -37.122384500713,-7.9245860488441 -37.11904223938,-7.9233955716106 -37.1187601948
SELECT *
FROM propriedades
WHERE ST_Intersects(
...
0
votes
3answers
308 views
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 ...
2
votes
2answers
466 views
Is there a way to get at C's OGRLayer.Intersection() or OGRLayer.Clip() in Python?
I am working with OGR in Python and noticed that the C libraries have useful Intersection() and Clip() functions as part of the Layer class. Is there any way to get at these functions in Python? I ...
4
votes
2answers
179 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. ...
5
votes
1answer
290 views
ArcGIS Intersect using Geometry Service
I am using the intersect service from the ArcGIS Geometry service.
referring : http://help.arcgis.com/en/webapi/sil....htm#Intersect
I have modified it to make it work with polylines
it works fine to ...
1
vote
0answers
112 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 ...
3
votes
0answers
394 views
How to find all intersections and count lines arriving at each intersection?
I'm having a hard time getting off the ground with this, and am trying to move away from ArcGIS / arcpy.
I have a shapefile with a network of polylines. I want to find/count all 2-way intersections, ...
3
votes
2answers
643 views
Find intersection points of two polyline features
I'm currently working with street intersections trying to find point(or points) where 2 given streets intersect(!disjoin). Streets are all Polyline features, and I have to work with 2 features at ...
