Process of creating geometric polygon features.

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2answers
66 views

How can I group Points to make polygon via Python

I have an array of coordinates Point= [lat,long] ListPoint= [[38.203655,-76.113281],[38.10,-76.12],..] I wanna make a polygon that contains all these points ? There is a project developed by ...
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0answers
38 views

How to generate random GeoJSON polygons (latitude, longitude)

I am looking how to generate polygons in GeoJSON format with random locations (latitude, longitude), if I generate totally random set of points it will not produce valid polygons. So my question is ...
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1answer
72 views

Python: Ray-trace a WGS84 point with heading and distance

One of my services defines geofences for a mobile app. The geofences consists of a lat/lon pair and radius in meters, in JSON, e.g.: { "geofenceId":"geofence_b39da38cff7be4b4693cbc31b2394bbb", ...
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1answer
59 views

How to create polygons from a polyline graticule?

I'd like to make a polygon shapefile out of a polyline shapefile showing a graticule. However, using the "Line to Polygon" tool results in a peculiar...something: Other standard tools like ...
1
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1answer
33 views

How to edit line and polygon layers at the same time?

I have two layers, lines and polygons. Lines are basically the boundaries of the polygons. Is there any way that when I change or reshape the lines the polygons get updated automatically? I normally ...
4
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1answer
65 views

How to grow several concave hulls until they completely fill a larger area without overlap?

This is my problem: I have a very large point layer with polling station locations across one country; each point belongs to a specific constituency (900k points, 4k constituencies). I wish to use ...
0
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1answer
35 views

How to copy closed loop lines into polygon feature class

I'm trying to utilize line contour data to find the volumes of local depressions. To do this, I want to copy the closed loops formed by depression contours into a polygon feature class to find the ...
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1answer
33 views

How to generate evenly sized polygons within a boundary

I have an area and need to create evenly sized polygons within the area. It doesn't matter where the polygons fall, only that they don't overlap and each area is the same. They needn't be ...
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2answers
51 views

How do I create blocks from a road network?

I have a road network and for every enclosed area within the network I want to create a polygon that represents that area. How does one do this?
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2answers
86 views

Shapely MultiPolygon Construction - Will not accept the entire set of Polygons

I am new to Shapely, so I am using a work request to learn a bit more about it. I need to execute a number of unions to build larger geometries from assessment neighborhoods in DC. I am curious ...
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2answers
98 views

How do I create a polygon layer from multiple touching line segments in QGIS?

I'm trying to create a base map for a Maine Coastal area, and wanted to create a polygon layer of the land cover from the coastline in QGIS. Whether I created the coastline vector layer from the USGS ...
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0answers
33 views

How do I optimize the speed and enable ArcGIS to create the Service Area around my locations?

The Problem: Every time I try to solve the service area around locations, ArcGIS crashes. It takes forever to load facilities and draw just a single polygon. How do I optimize the speed and enable ...
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0answers
99 views

Postgis - extrude a polygon

I want to extrude a polygon shape in postgis to create a pseudo 3D effect. To this end I have written a crude function to achieve it. This is very much test code and it creates a new Y vertice for ...
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0answers
48 views

Collection of polygons from a collection of points

I have a set of points, spread over a wide geographical area. I need to be able to create a set of polygons which best represent the clustered points. And I would like to create the clusters based on ...
0
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2answers
89 views

st_multi equivalent in Oracle spatial / how to convert polygon to multipolygon?

is there an equivalent to the PostGIS ST_MULTI available in Oracle Spatial? or - How can I convert POLYGON to MULTIPOLYGON in Oracle spatial? Regards, D
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2answers
98 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, ...
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3answers
281 views

Remove slivers from merged polygons

I am creating a single polygon by merging different polygons in ArcMap. When I merge them, slivers are created. So I have to delete those slivers manually. I don't have a license for ArcInfo so tools ...
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1answer
349 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 ...
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0answers
236 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 ...
2
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2answers
104 views

Tool for Creating Polygons

Does anyone know of any tools that exist for creating a polygons. I need to provide some employees with the ability to create shapes that detail the boundary of certain locations. So I just want a ...
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1answer
118 views

How to remove shapefile polygon vertex marker points in QGIS 1.8.0

I have created a shapefile layer and drawn a polygon to show the boundary of a woodland. How can I edit the polygon to remove the crosses that denote the intersection of two points on the boundary?
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0answers
42 views

Shapefile polygons disappear from backdrop map when re-opening QGIS project

I created a backdrop using Ordnance Survey OpenData VectorMap District and drew some polygons in it for which the shapefiles were (and still are) in the layer menu on the left of the screen. I saved ...
2
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1answer
55 views

POLYGON25D WITH OGR2OGR

I know how to convert a csv file with xyz coords to point25d with ogr2ogr and vrt file but the coords in the files are the vetices of 3dpolygon (firsth and last ones are the same coords). I want to ...
4
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1answer
161 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
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2answers
552 views

Is it possible to colour areas between (vector) contours?

...without making it a DEM first? Joshdoe seems to have done so ("Styled in QGis") here but doesn't say how. Thanks!
4
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1answer
274 views

create grid cells of fixed dimension around a point acting as a centroid

I've been trying to solve a problem for the last few days but not having much luck. I'm hoping someone here can point me in the right direction. I'm new to ArcGIS so I hope my explanation makes ...
3
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2answers
337 views

What Is The Ideal Workflow To Map (British) Postcode Territories

I'm looking for the best workflow for mapping postcodes and calculated territories, but being relatively new to mapping I'm struggling on a few details and also the best practices for displaying these ...
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0answers
93 views

How to draw polygons around known clusters

I need to split up an area into non-overlapping, but contiguous territories. I have n points on a map, which are partitioned into k sets. The partition is only partially geographic, meaning that ...
7
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2answers
161 views

Generating polygonal blocks using growing lines

We first generate a set of locations (i.e., points(x,y)), randomly. Then we assign for each point a number showing the angle of a line being centred at that point. The criteria for the length of lines ...
2
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1answer
145 views

How to make new polygon/feature from point which is NOT centroid?

I've spent all morning searching help sites and digging through the FAQs and worksheets but have failed miserably. I am an ArcGIS novice so I hope this is not too much of a "newbie" question but I'm ...
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0answers
93 views

Problems combining (union) Multipolygons in geodjango

I'm using geodjango and postgis (1.x), What is the best way to combine (union) a list of multipolygons. in what i assume is rather inefficient i'm looping trough like this combined = multipolygon ...
3
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0answers
160 views

building larger polygons from smaller ones *without* a common id in PostGIS

I am looking for a means, using PostGIS, of reconstituting a set of polygons from tens of thousands of smaller polygon 'pieces'. This is a simplified example, with the pieces shaded: Unfortunately ...
7
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3answers
322 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
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2answers
252 views

How to create a smallest quadrilateral concave polygon around GPS points?

I have this GPS track in a metric grid (Symbology by elevation, if anyone wonders): I need to define it's general area - for registrations and permits, with just 4 points. Therefore, I assume that ...
2
votes
1answer
613 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 ...
2
votes
1answer
199 views

Tearing in ggmap (R) after using spTransform and random point generation using splancs

I am using R and the package ggmap to try and generate some random points within the city limits of Chapel Hill, NC. I have downloaded the shapefile for the town of Chapel Hill from the Orange County ...
2
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1answer
315 views

Create a shapefile from geometry

Please excuse my lingo, I am still learning some aspects of geo spatial and arcpy. I have a python script that takes a shapefile. The shapefile consists of a polyline. I have traversed the polyline, ...
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4answers
388 views

How to create internal polygon without overlap on QGIS1.8.0

I would like to create new polygon inside the existing polygon. It does not means donuts polygon. I would like to have two polygon without overlapping. I can create if I don't check "Avoid ...
6
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1answer
482 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 ...
1
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1answer
215 views

Displaying only points within a polygon I created in QGIS?

Thank you in advance for any advice you might give me. I am new to qgis and believe what I'm asking is probably fairly basic. I am trying to map policing activity in NYC for two areas: one area in the ...
7
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3answers
1k 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 ...
5
votes
1answer
240 views

Simplifying polygons made from binary rasters

I'm using MaxEnt to produce a species presence / absence raster layer. It works fine but I have to choose a cut off point for what constitutes presence or absence. As a result I end up with a lot of ...
5
votes
2answers
865 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 = ...
2
votes
1answer
596 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
2answers
760 views

Problem creating polygon features using ArcObjects / ArcGIS 10

I need to create a grid of polygons. Each polygon is rectangle, thus has 4 corners (vertices). When I create polygon features using ArcObjects they seem to have wrong geometry, which results in wrong ...
0
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1answer
104 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 ...
6
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6answers
1k 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 ...
2
votes
1answer
830 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 ...
1
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1answer
1k views

Build Polygons from Polylines

I have to build the polygons from some polylines it is an area like a main land(with some boundaries) and some islands around it,islands are building polygons and main land is missing,when i have ...
2
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0answers
181 views

Right click editing menu disabled arcgis 10.0

Editing Polygon feature in FGDB, Create Features, Click Rectangle (in Construction tools), right click, unable to select any options (Absolute X, Y / Direction / Length) from popup menu. Help? Havn't ...