A region enclosing a point, line, or polygon at a specified distance.

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6
votes
1answer
579 views

QGIS define hexagon area around mapped points

I am using QGIS to map a number of radio antennas (for mobile network). Once I have the layer of the sites (done), I would like to assign to each site a coverage area (envelope). I could achieve that ...
2
votes
1answer
114 views

How to create a buffer zone for notification

I am new to PostGIS. I am working on a project, for this i need to find out abutter notification that generates a list of properties within the buffer zone from the selected property with user input ...
4
votes
1answer
278 views

Distance from waterways

I have an sdc file with water bodies, i.e. oceans-rivers-lakes. I want to combine it with a shapefile with the boundaries of countries all over the world and produce two measures: 1) The average ...
1
vote
0answers
215 views

Clipping points using buffer in Arcmap takes FOREVER

I'm clipping points (crimes) by using a buffer around a shapefile of city parks. There are quite a few records involved (2 million+), but it is still taking forever - as of now, the clip has been ...
8
votes
2answers
1k views

How to buffer a vector shapefile using ogr python?

I am trying to learn how to use ogr in python using the country and populated places datasets from http://www.naturalearthdata.com/downloads/50m-cultural-vectors/. I am attempting to use filters and ...
2
votes
0answers
378 views

Multiple ring buffer on point-shape error

I need to calculate multiple ring-buffers, but every time I try, arcgis produces a failure: Executing (Multiple Ring Buffer): MultipleRingBuffer Y:\GIS\RDY\clip\sn_clip.shp ...
4
votes
2answers
404 views

PostGIS algorithm to unite points of two geometries that are within specified radius

I want to find an PostGIS algorithm to unite points of two geometries that are "near" to each other. That is: I want a function, that takes as input two geometries, and returns 1 geometry, that ...
3
votes
1answer
777 views

How to Get the Three Nearest Points to an Object (different layer)?

I have two point shapefiles and I want for each point in the 1st shapefile to get the 3 closest (based on air distance) points from the 2nd shapefile. If possible, it would be great to have each of ...
6
votes
2answers
2k views

What's the Workflow for buffering in meters/km using WGS84 layers?

I'm a little bit new to GIS, so bear with me a minute.... I'm using QGIS 1.7.4-Wroclaw and working with an SHP layer in WGS84. I want to buffer out to a certain number of kilometers from this layer ...
1
vote
1answer
782 views

Create buffer-lines in QGIS alongside Vector lines

I am currently doing a map of a farm, to see which roads needs to be repaired. Those roads are either one sided fenced, on both sides fenced or not fenced at all. I want to make buffer lines around ...
0
votes
0answers
120 views

trying to make a point to polygon attribute join with a many to many match

I am trying to match US charter schools to noncharter schools in QGIS. I have constructed a buffer of 10 miles around each charter schools and then tried a join attributes by location match with non ...
0
votes
2answers
603 views

How to remove overlapping buffer in QGIS?

I wanna know how to do this in QGIS: I've tried many ways, but still can't find the right solution.
0
votes
1answer
124 views

Creating rectangle over a buffer circle with specified angles/rotation?

I have a layer that is a circle buffer around a point. What I want to do is create a rectangle around the circle, but have every rectangle be perfectly lined up N/S (0degrees of angle/rotation). I ...
4
votes
2answers
1k views

How to invert a Buffer(get the inside of a ring buffer)?

I have a line layer of a road network around which I create a buffer zone of 1000 m with Analysis Tools>Proximity>Buffer. But I am interested in the areas outside the buffer zone, and not the buffer ...
12
votes
4answers
2k views

How to buffer in pyQGIS?

I'm looking for some examples to do simple python scripts in QGIS. How would I do a buffer analysis on a dataset? I can't seem to find much in the manual and QGIS python that quite matches the Esri ...
3
votes
2answers
4k views

find location details within circle buffer

Wondering how would i go about getting this to work. I have a table with location data (lat, long, homevalue) in sql server 2008. Given a lat long say (32.113, -81.3225), i want to draw a 50 mile ...
1
vote
1answer
257 views

How to fit a polygon to a “best buffer” about a reference geometry in it?

If I have a polygonal geometry gbase, like a street (a rectangular strip), and a reference geometry gref, like a central line of gbase. The question is what is the function (here named BestBuffer) ...
3
votes
1answer
631 views

FME remove polygon holes of under size ### sqft and chop the ends off

Quetion #1 I have a wokspace that takes the latest version of my data and creates buffers and then merges those to one polygon. When 2 buffer polygons are near each other and close to create a hole. I ...
5
votes
1answer
475 views

How can I create a pollutant dispersion raster in QGIS?

As my previous questions have indicated, I am working on an air quality problem where I have a dataset of industrial emissions that consists of a location (long, lat), and an annual volume of ...
5
votes
1answer
158 views

How do I find location of minimum value within a buffer (around a point)

I have a digital elevation model (DEM) with a point location defined. I want to locate the lowest height values at a set distance from this point. I envisaged creating a buffer around the point ...
5
votes
3answers
809 views

Is it possible, in QGIS, to create buffers with a set radius, but with individual values taken from the attribute table?

I am looking to create an output that consists of an 11KM buffer around a number of discrete points, where the buffer has a value defined by a column in the data sets attribute table. Is this ...
2
votes
3answers
2k views

ERROR 000800 when trying to snap points layer to line or buffer layer

I am very new to GIS, so go easy on me. I am using ArcCatalog 10.0 and trying to snap a set of points to another layer that has roads in it. The points represent 10th miles along the road. Here are ...
1
vote
1answer
905 views

create buffer around locator-derived point

I am trying to create a buffer around a point derived from a locator search, using this example: http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples_start.htm ..but I am getting no ...
0
votes
6answers
3k views

batch buffer with python in arcgis 10

Hi friends: i have some feature class(7 feature classes) and I want to batch buffer in ArcGIS 10 . I don't know how can I buffer at once. Please help me. sincerely
5
votes
1answer
252 views

What is the width of the beach of a little island polygon?

This is a "classic" problem, that have no practical utility (see note-1 for applications), but illustrate another GIS problems... We can do some approximations to modeling the situation, the real ...
7
votes
3answers
605 views

Is there a st_buffer inverse function, that returns a width estimation?

When you supply a geometry g1 and a width w to the standard OGC function ST_Buffer, it returns a new geometry g2, g2 = ST_Buffer(g1,w) This question is about the inverse: a function where you ...
5
votes
2answers
223 views

Using newly created features in the next part of a python script

Good Afternoon I am trying to write a python script which buffers a large number of features from a geodatabase (but not all) and then dissolves the newly created buffer shapefiles together. ...
1
vote
3answers
924 views

In ArcMap, what is the difference between Copy Parallel and Buffer?

To build an offset of a linear feature in ArcMap, what is the difference between Copy Parallel and Buffer? In terms of the resulting features and their linear differences from the source linear ...
2
votes
1answer
627 views

Geotools // buffer using different CRS

I'm currently having a problem with Geotools. I try to generate a buffer (in meter using Lambert 72) on a map that has WGS84 as it's coordinatesystem. (problem is a bit like this one: ...
6
votes
1answer
2k views

ArcGIS: inside buffer with attributes?

How can I create buffers for polygons that a) lie only inside the polygon boundary, and b) know who their parent is? An example of where this is useful is First Nation Traditional Territories. There ...
6
votes
2answers
761 views

memory issue when trying to buffer/union large dataset using postgis

I am trying to generated a dissolved buffer of a large point dataset (Ideally 29 million points - Address data in Great-Britain, but I receive the data by chunks of 1 million points, so these could be ...
1
vote
1answer
673 views

How can I make a buffer with xxx meter by NetTopologySuite

I am very new in NetTopologySuite, I work with the coordinatesystem in WGS84 by lon/lat, with the NetTopologySuite. I found the Buffer function to create a buffer with a distance, but how can I make a ...
6
votes
1answer
411 views

How to generate non-merging buffers in QGIS?

I'm using QGIS to construct some fixed width buffers from a coastline shapefile. Is there a way to easily handle overlaps/ median lines? (I'm not sure if there's a particular term or phrase I should ...
0
votes
1answer
226 views

Buffer and Intersect differences

“What is the difference between ‘Select by location using a buffer or intersection’ and the ‘Buffer’ or ‘Intersect’ Analysis tools?
2
votes
0answers
384 views

Creating a Geodesic Polyline Buffer in OpenLayers

I have a feeling that the answer is going to be 'You can't do that without some very complex coding' but I thought I'd go for it anyway. I recently asked a question on how to create a Polyline Buffer ...
4
votes
2answers
4k views

Creating a Polyline Buffer in OpenLayers

I was wondering if there was a way to create a buffer around a polyline feature in OpenLayers. I have created a tool that allows the user to draw a circle buffer zone of whatever size and style they ...
3
votes
1answer
3k views

How to create a polygon (fixed width buffer) around a polygon in QGIS?

I have created a polygon in QGIS (in this case it describes a country's maritime baseline). I need to create a second polygon whose boundary is a fixed distance from the original polygon. (in this ...
3
votes
1answer
345 views

How to calculate buffer surface that falls within another layer's borders

The image below shows what two selected layers. One contains a series of borders, and the other a series of buffers. I am trying to obtain the buffered surface within each of the borders in the ...
4
votes
1answer
270 views

Surface covered by buffers in QGIS

In QGIS, I have plotted buffers around points. I would like to calculate the area which falls under buffers without over counting due to buffer overlaps. Is there a quick and easy way to do this?
8
votes
2answers
1k views

Growing a PostGIS geometry by a percentage

I'm looking for a way to add a buffer around a PostGIS geometry, but the size of the buffer should depend on size of the geometry. That is, I want each geometry to be enlargened by, say, 5%. The idea ...
1
vote
1answer
473 views

how can i use flat buffer for polygon?

i'd like to create flat buffer in a polygon shapefile .i try to use buffer tool in ArcGIS 9.3 but i could'nt select "flat" option in endtype combobox because the input feature is polygon .how can i ...
4
votes
1answer
403 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, ...
3
votes
2answers
954 views

Generate non-overlapping shapes from a buffer

I have a collection of points, and I need to generate shapes around these points. Let's assume that these points are locations of offices and that the shapes are the 'area of responsibility' around ...
2
votes
1answer
255 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
votes
1answer
171 views

Overlapping buffers - Doublecount points that fall within 2 or more buffers

I want to analyze crime around certain types of stores in a city. I made buffers around the stores and I need to a) select and extract crimes that occurred within those buffers, and b) join the two ...
4
votes
1answer
2k views

Best way to get Convex Hull/Boundary of millions of points

I've been trying to do some point analysis on some xyz data, I'm at the point where I've decided it is best to produce a boundary of my xyz files and put this with the metadata for each survey. Now ...
3
votes
1answer
1k views

How to obtain statistics within a Buffer/Catchment in MapInfo?

I need to calculate the population statistics within a 10 minute drivetime catchment from a point and within 1 Km Buffer from a point in MapInfo, how can I do that can someone please elaborate? I have ...
2
votes
1answer
272 views

how to extract overlap from non-dissolved buffer zones in qgis 1.7.4

I have a shapefile with the inventory of all limetree in a region. I made a buffer around each tree. So, the place where buffers overlap each other is the best place to put beehives. Is there a way ...
3
votes
2answers
2k views

ArcGIS 10: How to clip point buffer to features in another layer?

I'm on a steep learnig curve here, so aplogies if my question is a one-banana problem. In ArcGIS 10 I have a contour layer that was generated from an ESR ASCII raster file (batyhmetry of the South ...
5
votes
2answers
776 views

Create a polyline buffer with Arcpy

I'm trying to write a python script with ArcPy that draws arcs and I've achieved something with creating a buffer and then clipping it with a bounding box so I only keep the length I need (I thought ...