Process of creating geometric polygon features.

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3answers
38 views

How can I insert a bounding box or polygon in a PostGIS geometry field?

I have a field in my table called 'geometry' that was created thus: CREATE TABLE "public"."sites" ( "id" int8 DEFAULT nextval('sites_id_seq' :: regclass) NOT NULL, #... A few MORE fields ...
12
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5answers
8k 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: ...
0
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1answer
137 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 ...
2
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0answers
43 views

Weird-looking France after OSM import with osm2pgsql

After importing france-latest.osm from Geofabrik, using osm2pgsql, it seems that the polygon attributed to Metropolitan France (osm_id = 1403916) is a bit odd: I'm far to be a geography expert, but ...
6
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1answer
232 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
1
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1answer
42 views

Dynamically drawing a polygon around another shapefile, ArcGIS 10.2

Let's say I have a vegetation raster that indicates the density of forest all over the world. I also have a shapefile that contains the admin boundaries of each country in the world. The easy part is ...
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1answer
30 views

Raster domain output polygon has is an empty feature class. Shape_Length and Shape_Area = 0

I am trying to convert a 32-bit floating point raster with 205289 columns and 120615 rows to a polygon using Raster Domain. It creates a feature class that does not contain any polygon. There is a ...
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3answers
966 views

How to find line length in QGIS while editing?

I am using QGIS (before, I used ArcView). 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 ...
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1answer
27 views

Creating contiguous / adjacent ellipses

I've only just started using drawing tools in ArcGIS, and have the following question I haven't found the answer to online. Is there a way of taking a drawn ellipse (at a slight angle) and adding say ...
0
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1answer
37 views

Adding custom shapes to a new shapefile

I am using ArcGIS 10.1 and I drew a rectangular shape to designate a junction on a map and i would like to add that to a new shapefile. Could you please give me some ideas.
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1answer
54 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
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1answer
42 views

Difference between 'point' and 'WKSpoint' in ArcGIS

I have to add 3-D points to make a polygon in ArcGIS using VB.NET. I have defined an IpointCollection and want to add points to this. I have options to add 'point' or 'pointcollection' or 'WKSpointz'. ...
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3answers
409 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
33 views

“Flood fill” polygon capture mechanisms in various GIS

Within our organisation we have a requirement to capture lines dividing land into chunks and then to create polygon features using aggregates of these divisions. In the example image below ...
0
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2answers
81 views

I have a table with a series of lat/long points - how do I convert them into polygons?

I have an Excel sheet with about 150 points (lat and long in decimal degrees) which belong to about 15 different polygons. The columns I have are FID, NAME (the same between polygons), POINTS (points ...
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1answer
286 views

How to create a polygon feature class from polylines in Python Arcgis?

I am trying to create a polygon from polylines. I've created this script but it gives errors of Arrays. Thanks. import arcpy polyline=r'C:\temp\temp_lines.shp' ...
0
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2answers
111 views

creating isochrones in postgis/osm2po/pgrouting and then saving the isochrones as polygons

So I am creating some isochrones in pgrouting based upon a table from osm2po. Now I have a query that will get all of the edges that are c driving distance away from a point. My question is, how can I ...
0
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0answers
12 views

creating Polygon from LineString and a width

I have to create a Polygon from a lineString and a width. Ex: Given a street as a lineString (Or a list of points) and a width, create the polygon (the road). I am using Geotools, but I couldn't find ...
0
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2answers
145 views

How to create polygons from unclosed polylines?

I have a layer of driveway that is in polylines unclosed . They are just two parallel lines outlining the width of the driveway. Then again, there is a gap (sidewalk layer) and driveway continues ...
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3answers
477 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 ...
16
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1answer
4k 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 ...
2
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1answer
103 views

Convert SpatialGridDataFrame in to polygon shapefile in R

I have a SpatialGridDataFrame in R and want to plot just one of its attributes as as polygons in a GIS. There seems to be no simple way to do this. The situation is complicated by the fact that the ...
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2answers
79 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 ...
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2answers
149 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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1answer
3k 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?
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1answer
112 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 ...
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1answer
172 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", ...
14
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3answers
2k 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 ...
2
votes
1answer
758 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 ...
1
vote
1answer
42 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
votes
1answer
129 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
58 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 ...
0
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1answer
48 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
56 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
142 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, ...
2
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2answers
172 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 ...
2
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1answer
168 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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2answers
186 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
68 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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6answers
2k 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
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0answers
157 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
52 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 ...
2
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1answer
58 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 ...
0
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2answers
157 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
2
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2answers
2k views

Creating fixed width polygons in ArcMap

I've been adding easements, which typically have a fixed width. Are there any existing tools or scripts that would allow me to define one edge and automatically create the other? The buffer tool is ...
5
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2answers
141 views

Create polygon from page size

Is there an easy way to create a polygon that matches the data frame in my page layout? I'm trying to set up data driven pages and want to have it key off of polygons that frame the boundaries for ...
2
votes
1answer
939 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 ...
3
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3answers
519 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 ...
0
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1answer
195 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?
2
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1answer
246 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 ...