Process of creating geometric polygon features.

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20
votes
2answers
7k views

Dividing 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
3answers
2k 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 ...
4
votes
2answers
3k views

Colouring areas between (vector) contours?

Is it possible to colour areas between (vector) contours without making it a DEM first? Joshdoe seems to have done so in Create filled contour map with GRASS but does not say how.
7
votes
2answers
21k views

Create polygon layer from polyline layer

Our systems expect polygon shapefiles, representing a collection of non-intersecting and geometrically valid (multi)polygons. Specifically, farm fields. We often receive our representations of farms ...
13
votes
6answers
13k views

How do I create a convex hull in ArcGIS Desktop?

I would like to be able to create a convex hull in ArcGIS Desktop 9.x, but I cannot find an appropriate tool. How does one go about creating one? I am interested in answers for all license levels: ...
16
votes
3answers
3k views

Producing building shadows using ArcGIS Desktop?

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 ...
10
votes
5answers
19k views

Creating polygons around extent of similar points using ArcGIS Desktop?

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 ...
11
votes
6answers
7k 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 ...
8
votes
1answer
2k views

Polygon creation (Clockwise rotation or not)

According to "ESRI Shapefile Technical Description An ESRI White Paper—July 1998", Vertices for a single, ringed polygon are, therefore,always in clockwise order. Otherwise,"Dirty" polygons occur when ...
5
votes
3answers
3k views

Finding line length while editing in QGIS?

I am using QGIS. I would like to know if there is any way during the editing phase of a vector (line or polygon) to know the length of the line (total and partial) that is being created?
5
votes
3answers
2k views

Creating collection of polygons from collection of points?

I have a set of points, which are spread over a wide geographical area. I need to be able to create a set of polygons which best represent the clustered points. In parts, some points may simply lie ...
2
votes
1answer
1k 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 ...
5
votes
2answers
5k 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() ...
4
votes
1answer
2k 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 ...
0
votes
0answers
78 views

For every point create a wedge

How does one create a wedge polygon from a point? If I have 2000 points, I want each to have a wedge starting at each point with each point having a defined azimuth that the wedge points toward. That ...
0
votes
3answers
539 views

How to generate polygons upto the edge of other polygons?

I am doing some work on a pipe network (blue lines) and I am trying to attribute the information about the street to the pipes. I have 2 polygon layers one of the blocks (green hatch) and one of ...
8
votes
6answers
4k views

How to split a polygon into quadrants?

I have a Alberta province (Canada) section polygon shapefile in GCS_NAD83 with 255,000 polygons. I like to split each section into 4 equal quadrants (NW, NE, SW, SE) The Alberta province has ...
11
votes
1answer
3k 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 ...
5
votes
1answer
2k 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
2k views

How to create a grid constrained within a polygon in QGIS?

In QGIS I have created an irregularly shaped polygon. I can create a grid based on the maximum extents of the polygon via Vector>Research Tools>Vector Grid. However, what if I need the grid to ...
9
votes
1answer
5k views

Postgis - Converting 'geometry_dump' data type to a 'geometry' type

I am working with a dataset of property boundaries that has had ST_Union() run on it, thus all the polygons appear as a multi polygon in one row of a table. I would like to separate these out so I get ...
5
votes
2answers
2k views

Why does this simple Python OGR code create an empty polygon?

Please excuse my ignorance...I am new to Python OGR. I am trying to create a simple square polygon and fail...this produces an empty polygon. Where did I go wrong? from osgeo import ogr driver = ...
4
votes
1answer
435 views

How to generate overlapping polygons from lines output from Table To Ellipse tool?

I have a feature class of line-based ellipses generated by the Table to Ellipse tool that looks like this: What I want is polygons of the individual ellipses, however tools like Feature to Polygon ...
3
votes
1answer
186 views

Create mosaic like Voronoi Diagram from disjoint polygons

The illustration below shows the problem: as in (a) I have a set of disjoint polygons, as geometries in PostGIS. I need something like (b), the "mosaic" of this set of polygons, building it by a "...
3
votes
3answers
408 views

Creating polygon from 2 txt files (Parent ID + Coordinates)

Here is what I am trying to do: I want to create polygons based on two separate text files: the first one (as parents) lists the Polygon ID (ID_el) and three to four Points ID (IDpt1, IDpt2, IDpt3..) ...
2
votes
0answers
887 views

Topography: How to convert raster into vector layers?

(nb:This project is part of the #Wikipedia #wikimaps project) 1. Question: How to create vector topographic maps from raster image ? How to convert raster topographic image into closed vector ...
6
votes
3answers
4k views

How to subtract (erase) polygons from polygon?

I have two polygon layers, one is green that represents all non-public right-of-way land. I have another polygon that is just a circle with a specified radius. I would like my output to be a polygon ...
2
votes
2answers
18k views

ArcGIS: Create polygon using file containing point coordinates

I have a text file containing the projected coordinates of the points that define a single polygon. The X, Y coordinates are separated by Tab Is there a tool in ArcGIS similar to "Add X,Y Data" in ...
3
votes
1answer
2k views

How to draw a polygon with preset length in OpenLayers?

For a project I am working on, I need to be able to put a polygon on a map using OpenLayers, based on a variable point that can be set by a user. The polygon is an isosceles triangle of which two legs ...
2
votes
1answer
137 views

How to draw a polygon between a number of polygons automatically

The weight “empty” area which is bounded by the orange boundary should represent a land use “Roads” so I should fill it with polygons. Now my question is how to fill these empty areas with polygons ...
2
votes
1answer
2k views

how to connect points to create a polygon boundary in QGIS

I have 31 points in a shapefile, which delimit a field (it's an irregular shape). I want to connect those points so they create the boundary of a polygon. Does anybody know a kind of "connect the dots"...
2
votes
1answer
3k views

combine several polygon objects in one polygon object with geotools (is it possible)?

I have several polygon objects and I need to "merge (or combine or dissolve)" them toghether into one polygon object. With a GIS tool like Quantum GIS, I do this with Geoprocessing option "Combine ...
2
votes
1answer
4k 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 ...
2
votes
1answer
2k views

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

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 ...
1
vote
1answer
7k views

How to create a circle with specific radius? [duplicate]

Possible Duplicate: Conflicting measurement units with buffer ftools I have a shapefile as input. How could I create a circle with a radius of exactly 500 meters, using QGIS?
1
vote
2answers
604 views

Automatically create polygons from top right and bottom left coordinates?

I have a CSV file with hundreds of records. Each record contains 2 matching coordinates, 1) top right corner of a rectangle, 2) bottom left corner of a rectangle. Polygon ID, Lat 1, Lat 2, ...
1
vote
1answer
469 views

Polygonizer plugin for QGIS 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 ...
1
vote
1answer
149 views

Distance analysis of 3-D surface in ArcGIS using VB.NET

Using VB.NET I created a 3D polygon in ArcGIS to model a fault plane and now I want to find two different distances from a point on earth's surface. How to go about this? Can some one help with the ...
0
votes
0answers
58 views

Complexity of US 5-Digit Zip Code Boundaries from Scratch?

Does anyone have any idea how difficult it would be to create 5-digit zip code boundaries from scratch? Let's suppose you start with a good outline of the US. Where would you source the fundamental ...
0
votes
0answers
126 views

Dividing a polygon into certain areas (open source solution preferred)

I have a polygon with an area of 50.000m². Now i want to devide this area in two polygons of different areas with a line layer. The left polygon should have an area of 30.000m² and the right polygon ...
0
votes
0answers
1k views

Why is a Shape polygon file not editable?

I received a .shp polygon file. When I choose the edit toggle tool in QGIS the little red X's appear as expected. Then when I try to edit the polygons such as add a polygon all seems to go well, when ...
0
votes
0answers
122 views

Drawing boundaries between discrete features based on attribute values in ArcGIS for Desktop?

There is a point feature class with a certain numeric attribute (let us say, populated places with population). I wonder if there is, in ArcGIS, a way to draw polygons such that the sum of the ...
0
votes
2answers
526 views

Drawing BTS sectors in GSM?

I'm very new to Mapbasic. I tried to make a short code to draw some BTS in GSM but I can't do thant (over 1 month). I have a table with these column: Sitename, Lon, Lat, Azi, Beam, Dist. Can ...
-1
votes
1answer
49 views

Adding polygons on points using Arcgis 10.2

I have a series (300+) of points and I would like to apply polygons over it. Cannot use the buffer tools as the polygons are not symmetrical but I basically need the same geometry for each one, ...