Tagged Questions

Process of creating geometric polygon features.

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16
votes
1answer
3k views

How to divide a polygon into specific sizes using ArcGIS?

I have several thousand irregularly shaped polygons in a shapefile. I want to be able to split each polygon into three areas, and to specify what the size of those areas (they sum to the previous ...
10
votes
6answers
5k views

How do I create a convex hull in ArcGIS?

I would like to be able to create a convex hull in ArcGIS 9.x, but I can't find an appropriate tool. How does one go about creating one? I am interested in answers for all license levels, ArcView, ...
14
votes
3answers
1k views

Producing building shadows?

How would you generate building shadows from building footprints? I have attribute values for the heights of buildings. So would preferably like to have the shadows' sizes vary based on that. The best ...
4
votes
6answers
5k views

Points to Polygon

I've millions of points collected for lithology layer. They have used a coding for different types of rocks. I need to create a polygon around the extent of similar points. What is the easiest way to ...
2
votes
1answer
515 views

Create new polygon layers from postcodes latitude & longitude

First at all, I want to say that I am geocoding enthusiastic but have no formal background on GIS. I'll do my best to use the right wording and make myself clear what I am striving for. Also the only ...
4
votes
1answer
869 views

Create overlapping polygons from contour lines

Working in ArcGIS 10, I have a set of contour lines representing density of commercial square footage, and I have a set of points representing local maxima for each peak of the dataset. For each ...
8
votes
1answer
762 views

Polygon overlay with Shapely

I'm trying to capture all the non-overlapping polygons indicated below using Shapely (given polygons A,B & C). Moreover, I'm hoping to do so without iteration, testing for intersect etc. The ...
9
votes
6answers
1k views

How to find the boundary co-ordinates from a given set of co-ordinates

Given a set of coordinates, How do we find the boundary coordinates. <== Figure 1 Given the coordinates in the above set, How can I get the coordinates on the red boundary. Boundary is the polygon ...
6
votes
1answer
84 views

How to apply the four colors theorem in a polygon map in ArcGIS/ArcToolBox automatcally?

I need to apply the four colors theorem in a polygonal shape in a way that I do not need to choose manually each color to put in each region. I wish to knows if there is any extension, plug-in, script ...
3
votes
1answer
681 views

ArcGIS 10.0/arcpy: How to create a polygon geometry from inner and outer ring point arrays?

I have two arrays, each containing a closed ring of points, one for an outer ring and the other for an inner ring, the latter running counterclockwise, of course. I am using the arcpy.Polygon() ...
3
votes
1answer
340 views

How to programatically populate a shapefile field with polygon areas in OGR?

I'm trying to programatically populate a shp field with polygon areas: import sys import ogr ds = ogr.Open( 'tttttttttt.shp', update = 1 ) if ds is None: print "Open failed./n" sys.exit( 1 ...
2
votes
1answer
1k views

clip polygon with the extents of contour polylines

I have a polygon shape that represents the boundary of Fennoscandinavia and a polyline shapefile representing two contour intervals for a trait. I would like to create a new polygon representing the ...
1
vote
1answer
568 views

How to create multipart line and polygon with interior ring in ArcGIS Python?

My objective is to swap X,Y coordinates of feature classes using Python and arcgisscripting. Based on help examples, I managed to write script which reads and writes all geometry types. The problem ...
0
votes
1answer
193 views

Polygonizer plugin halts in Windows

I've had some success and some problems using the Polygonizer plugin in the past. I'm using Polygonizer 2.1 in QGIS 1.8 on Windows 7. I'm aware there are sometimes problems using Polygonizer in ...