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

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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
908 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
229 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
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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
712 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 ...
0
votes
1answer
289 views

Generate a report or table for buffer zone

I have a polygon feature class. I create a buffer for this feature with a distance being 2 km.Now the buffer output intersect with features of the original polygon.So say for instance from the orginal ...
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vote
2answers
247 views

Buffer point dataset based on compared value

I am creating polygons from the dissolved buffers of points and need to control the dissolve process. In the model the first stage is to assign high/med/blackspot using the following f2='ERROR' def ...
3
votes
1answer
289 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 ...
2
votes
2answers
157 views

After two buffers operations (+/-), why is the result file bigger than the original?

First file ( .shp ) had 1000KB, after 2buffers ( buffers on polygon, 1st buffer +100, 2nd buffer -100 ( small things near polygon should be removed )) in quantum gis file grown to 1500KB, and after ...
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vote
1answer
501 views

Converting distance between nautical miles and degrees

This is such a basic question that I'm kinda of embarassed. Here is the situation: We have a certain funcionality developed that: Will check for a tolerance value (this input is given by the user ...
4
votes
2answers
2k views

Multiple ring buffer with attributes

Building on ArcGIS: inside buffer with attributes?, I'd like to be able to create multiple ring buffers, while retaining (and possibly dissolving on) attribute values. How can this be done?
2
votes
2answers
423 views

Buffer in ArcGIS v. ArcINFO 9.3

I have ArcGIS 9.3 and my question is regarding Buffering. Is that only allowed in ArcINFO or is there a way to use a buffer in ArcGIS?
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vote
1answer
312 views

Best practices to minimize error when buffering unprojected data

If I buffer hundreds of unprojected WGS84 points across the US by say, 3 miles, will I get accurate areas returned (3 x pi x r) for each of the circles created? I suspect not. If not, what would be ...
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vote
1answer
470 views

How to use buffers to estimate the attribute data for a given polygon?

I have two layers: point and a polygon. The point layer has lat/long and I have created buffers of a 1/4 mile. The polygon layer has data such as age and income. Is there a plug-in that can ...
3
votes
1answer
1k views

How to Buffer with intersections in QGIS

I am buffering a layer of facilities (points). I will then use the buffer to clip and intersect another layer, containing resources. I want to answer the question, how much of the resource lies ...
3
votes
1answer
949 views

Buffer Selected Line Segments Using ArcGIS 10 or Python

I haven't quite found a solution for buffering selected line segments of a road network without extporting the selected line segments to a new file and then buffering. I want to avoid creating a ...
5
votes
1answer
1k views

How to calculate the size of a particular area below a buffer in QGIS

I have a point shapefile of villages where data was collected in Northern Kenya. I created a buffer around those villages. The second vector layer contains polygons defining areas according to ...
5
votes
2answers
1k views

Need help calculating forest cover within a buffer when it overlaps with other buffers

I'm new to ArcGIS and having real trouble getting this done… Hopefully someone can help. Thanks in advance! I have a layer showing forest cover in a landscape. I'm trying to create a 5km buffer ...
5
votes
2answers
294 views

How can I create a “setback” buffer in QGIS?

I've been going a bit crazy in trying to create a "setback" buffer on QGIS for coastal lines in a map projecting this buffer outwards towards the sea. I've managed to create a normal Bidirectional ...
2
votes
1answer
2k views

ArcGIS10 - How do I dissolve two different buffers together so they are not overlapping?

I am trying to find out how many registered sex offenders live within 2,000 feet of a school/park in a specific county. The park buffer and school buffer are dissolved but not together. I am also ...
5
votes
3answers
2k views

When should I use ST_Buffer?

I would like to know what is the sense of using st_buffer operation. In PostGIS reference guide there is only the syntax and a short description of this operation. Could you give some examples to ...
4
votes
1answer
474 views

QGIS inside buffer with attributes

Fairly similar to ArcGIS: inside buffer with attributes? but in QGIS. It would be convenient if the buffer layer inherited the attributes of the parent. Also I am doing inside buffers (-ve distance ...
7
votes
3answers
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Use buffer tool to draw different radii?

I am new to Arcmap-Arceditor 10 and could really use your help. I have been mapping ethanol plants (which utilize corn to produce ethanol) and corn production amounts in the counties of the USA. ...
5
votes
3answers
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How can I display with OpenLayers the geometry returned from a ST_Buffer in POSTGIS?

Im using PostGIS, GeoServer and OpenLayers, and the thing is that i want to display the geometry result from a query like this: SELECT ST_Buffer(ST_GeomFromText('POINT(100 100)'), 500); To perform ...
0
votes
2answers
466 views

how do you do a buffer analysis of a geographical location?

I want to use a buffer analysis to identify the geodemographics of Incinerators. I have downloaded the Output Area Classification (OAC) map and also know the locations of all the Incinerators I want ...
4
votes
1answer
290 views

Select points within 2 buffers

I have 2 huge files of points (hundreds of thousands of points). I need to determine a way to loop through all the points in one file and find all the points in the second file that are only a ...
3
votes
3answers
5k views

How to create a polygon buffer from a line?

I have connected a series of points into a line in ArcMap 10 with the Points to Line tool in the ArcToolbox. The line is, of course, in its own layer, and I added a 5 meter buffer around the line. It ...
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vote
2answers
698 views

Error adding buffer to polyline in ArcMap 10

As the next step to what I did in this previous question, I would like to add a buffer to a polyline, with 5 meters on either side. I tried adding buffer to two versions of the line, one in ...
3
votes
1answer
589 views

datum conflict when creating buffer in arcgis 10

A buffer I created successfully executed, but I received the following message: "WARNING 000632: Datum conflict between map and output." How can I fix this?
3
votes
2answers
2k views

How can I use the Buffer Wizard in Modelbuilder or arcpy? (ArcMap 10)

I am creating a model in ArcMap 10 and I need to use the Buffer Wizard tool to create multiple buffers within a polygon feature class. The problem is, I can't seem to place the Buffer Wizard within my ...
12
votes
5answers
763 views

Simulating the expansion of polygon features

I've got what I'm hoping will be an interesting question. I'm working on an assignment for an intro to GIS course that uses some Gulf oil spill data to introduce common vector-based spatial analysis ...
1
vote
2answers
1k views

“Item not found in this collection” when trying to set the Shape on IFeatureBuffer

I'm working on code to open a 3rd party data file and convert it into a collection of features in a custom layer based on FeatureLayer. I have had no issue importing the data itself (nodal data for ...