2
votes
1answer
34 views

Delete duplicate polygon nodes with PostGIS

I'm trying to delete duplicate nodes from a shapefile with QGIS, but after running the tool to delete it, nothing happens and shows the same errors. I thought that maybe importing to postgis could be ...
0
votes
1answer
55 views

The best way to convert points to polygons using ArcObjects

I have a set of points from GPS I want to convert them to polygons..I have two approaches to do this.1- convert points to polygon..I do this with below code: private IPolygon ...
2
votes
2answers
65 views

QGIS polygon centriods - How are they created?

I have been using QGIS to analyses spatial data and I created polygon centroids with the vector geometry tools. Now for a report I have to explain how these centroids were created. I have not been ...
0
votes
0answers
46 views

how to remove a point or polygon in shapely python

I want to place minimum number of sensors(circles) to cover a maximum area(polygon). I am using "Shapely",python module. I want to know if a sensor i.e a point buffer inside the range of the other ...
1
vote
1answer
81 views

Iterating over all features in featureclass to intersect them individually with polygon using ArcPy?

I've got a point featureclass, and I'm trying to individually intersect each feature with a polygon featureclass to get some information about which polygon each feature is in. I did one intersect ...
0
votes
1answer
41 views

converting random point order into polygons

We received a kml file with polygons but the points are not in a logical sequence and we end up with strange overlapping shapes that are supposed to be an open polygon. We did identify a point near ...
0
votes
1answer
61 views

How to calculate point from lat/long, angle, and distance? [duplicate]

I am trying to calculate the point from a given lat/long, a bearing, and a distance. This is for plotting weather given a aeronautical way point. For example: Given a waypoint with a known ...
2
votes
1answer
48 views

Spike finder in PostGIS

I tried to modify spikeRemover from Schmidt & Kr├╝ger. My goal it's to obtain, for each polygon, the position of the spikes. I don't need to remove it. For some reason, that I can't figure out, my ...
2
votes
2answers
223 views

Change points to polygon

I have a map which has one data point per zip code. I would like to change those points to zip code polygons. Any ideas on how to go about it?
0
votes
1answer
44 views

Extract address data / Query point in administrative boundary

I try to create a DB in postgreSQL with all the postal adress data for a specific country. Actually I have this table full of data: id integer NOT NULL DEFAULT nextval('plz_id_seq'::regclass), ...
-1
votes
1answer
52 views

Determining if polygon contains point to populate point's field with polygon's name using arcpy.da?

Am trying to check if the points in a point shapefile are contained within a polygon shapefile and if so, to populate a field in the point shapefile with the name of the polygon and to populate the ...
1
vote
0answers
36 views

Authoring map with advanced gradient symbol for ArcGIS web service?

I need to prepare a web service which will display the gradient of polygon points values. It has to look just like in this picture: link to the picture (please ignore the arrows). Each polygon is ...
0
votes
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 ...
1
vote
1answer
43 views

How to compare multiple spatial point patterns over a polygon

I have multiple point pattern distributions over the same region/polygon. Each point pattern distribution has different number of points. Here is an example of two spatial point patterns for the ...
0
votes
0answers
35 views

Split polygon into four with respect to single point

Some days ago one of my colleague came to ask me a query related to Geometries. The situation is as....There is one Polygon(suppose a city polygon) and there is one point(suppose user's current ...
1
vote
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 ...
0
votes
1answer
46 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
0
votes
1answer
44 views

Get all points with in some range of a point (or range of point)

I have got a list of points and a fixed range (10m). So what I have to do is for each point I have to find all the points present in a table with the 10m range of the given point. For example: Let ...
1
vote
1answer
48 views

Identify geographic location to points

I am quite new in QGIS and I really need your help. I have a map of Kenya divided into 68 districts and I have coordinates of 30.000 schools. The points have one variable besides the latitude and ...
1
vote
1answer
67 views

How to map flood areas from a set of points containing surface and height of water?

I am working on the damages made by the typhoon Haiyan. I use QGIS 2.0 with extensions and toolbox, and MapInfo. I have vectors, rasters of the place. I want to map the flood area along the ...
7
votes
2answers
796 views

How to remove small “salt & pepper” polygons from a layer?

I have a map made up of multiple polygons, with a few hundred thousand points very small polygons on within it. I need the larger polygons, but not the points small polygons. How do I select and ...
1
vote
2answers
95 views

QGIS point sampling tool really slow for polygons?

I have a large field of randomly distributed points (100,000 of them to be precise), and I'd like to get values for a variety of raster and polygon coverages for each point. I've been using the QGIS ...
1
vote
0answers
107 views

Divide polygon based on points for even distribution

If I have a point layer, how can I create a polygon that includes all of the points and divide that polygon into n sections in which each section contains an equal number of points? Preferably in ...
3
votes
2answers
109 views

Determining closest representation of polygon as collection of points+radii

Have a bit of a tough question, which I realize there may not be an easy solution to. Figured what better place to ask. I'm attempting to transform a polygon into a series of arbitrary points with ...
3
votes
2answers
396 views

How to do a Point to Polygon analysis with multiple variables?

I have a database of almost 10k crimes, which are divided in to 10 categories and plotted on a map I also have a database of 12k addresses, which are also plotted on the map. I aim to perform a ...
0
votes
1answer
819 views

How do I write a MYSQL spatial query to find all polygons (rectangle) that contain any points in a table?

Something like: SELECT * from polygons WHERE bounds CONTAINS(SELECT geom_point from points) Can someone help me out with the syntax? Bounds will always be a rectangular polygon and everything is in ...
0
votes
0answers
89 views

How to convert a set of points to a polygon based on a specific field in QGIS

I am having a point shapefile that consists of a number of point sets. I need to convert these points to a polygon based on a particular field in attribute table say for example locality . How can i ...
3
votes
1answer
66 views

How many polygons under a point (ArcGIS solution preferred)

Opposite of Point in Poly. How many polygons underneath a point. I have a point layer with many points. I have a polygon layer with many polygons. I need to add an attribute to the points that ...
1
vote
1answer
136 views

Sum of point attributes inside hexagons using QgiS UI

I'm very new to Qgis so I would very much appreciate any help you can give me. I have a point shapefile that corresponds to locations of animals captured. I've joined a table to this shapefile with ...
4
votes
2answers
374 views

How do I find the average distance within a polygon to a point?

For my purposes, I can assume a homogeneous distribution of points within the polygon. What I want to find is the average distance from points within a polygon to a specified point. I don't know where ...
3
votes
2answers
378 views

How to average values in a point layer with respect to polygon layer in QGIS?

I am new to GIS and have the following problem: I have 2 layers: a point layer with a column that contains numbers (pollution index from specific measurement point) and a polygon layer with different ...
0
votes
1answer
90 views

QGIS create point data attribute as the name of the polygon it falls in

I'm working in QGIS with a point data set overlaying a farm with 140 fields. While I can analyse the points from each field individually, I would rather use an awk script to calculate statistics I ...
2
votes
0answers
203 views

Divide polygon layer by point layer in QGIS?

I have two layers - one polygon layer that is a buffer of a road layer, and one point layer that shows certain locations along that road. What I want to do is to divide/split the polygon layer at the ...
3
votes
1answer
968 views

Problems converting polygon to point [closed]

I'm trying to convert polygons to points with ArcGIS 10. My polygon layer has 2 attributes that I want to give to my point layer. I'm using the Feature to Point function from the Arctoolbox, but it ...
1
vote
1answer
302 views

Aggregate points with same values to polygons

I have a shapefile with 2M measurement points (each measurement point has a resolution of a 1/10). How can I aggregate points around each other if and create polygons out of it? They do not have to ...
3
votes
1answer
280 views

Convert polygons to a number of randomly located points based on polygon size

ArcMap 10.1 on a PC. Working with a large shapefile with ~50,000 poygons with a wide range of size from 1,000+m. to <1m. I would like to convert these polygons into points so I can do some analysis ...
1
vote
0answers
159 views

How can I move two layers at once in QGIS?

I'm trying to move two digitized layers, one containing points, the other polygons to a different location at the same time. QGIS doens't seem to allow this. Even if I select both layers and features ...
1
vote
1answer
119 views

Split polygons and extract points

I have a polygon file with 90 adjacent polygons. I also have a lat/long point file that overlaps the entire surface of the polygon file (170,000 points). My problem is that working with all of the ...
1
vote
1answer
648 views

arcpy points in polygon check

I have a list of points and a list of polygons both in a separate shape files. I am trying to write a ArcPy script to loop through the points, and then the polygons respectively and tell me when a ...
0
votes
3answers
336 views

Calculate 'Rectangle' Coordinates Given 2 Points and width [closed]

I want to create a rectangular polygon using two points as guides. So let's say a journey starts in Egypt and ends in London, my polygon should have 4 points: 10 miles further from London than Egypt ...
0
votes
0answers
43 views

Point to Polygon [duplicate]

Possible Duplicate: Create new polygon layers from postcodes latitude & longitude I'm running QGIS 1.8.0 I have a list of points that I need to convert to one polygon. So far I have ...
6
votes
1answer
333 views

How to draw shapes with highest possible decimal accuracy

I am trying to read input of lat and long to draw the shape based on condition.The input is standard array of lat and long with 15 decimal accuracy. I am realizing - I am loosing some decimal accuracy ...
4
votes
1answer
3k views

Arcgis 10: Point layer, polygon line layer, draw points to the nearest polygon point or other nearest line?

I have been using arcGIS for a while now but I often get frustrated with it :( I have version 10.0 arcGIS and I'm have two layers 1) Point data (building locations) 2) a polygon shape file (outline ...
4
votes
1answer
779 views

How to automate the drawing of polygons (square) around a number of points in QGIS?

In QGIS (or alternatively any other scripting + GIS stack), how can I automate drawing a 100km x 100km square around a number of points, with the point being dead in the center? I'd need to loop ...
0
votes
0answers
436 views

How to do a spatial join if QGIS 1.8 keeps crashing?

I am trying to perform a simple spatial join (adding polygon data to points) in QGIS 1.8: target vector: points join vector: polygons take attributes of first located feature keep all records ...
2
votes
0answers
511 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
3
votes
2answers
983 views

How can i select a polygon in MS SQL 2008

I am very new to MS SQL 2008. I got a task to select a polygon from the polygon layer by giving the X-Y coordinates. I already got the script for PostgreSQL for the same thing, but i need it for MS ...
2
votes
1answer
764 views

Geometryutil, simplify polygon, querytask and query fault error

One of the tools in my app is to draw freehand polygons (counties) to show points (companies) in each county. Everything works great but if the user creates an intersecting polygon then I have a ...
2
votes
3answers
949 views

Accessing coordinates of polygon

I have designed a polygon in a web page and the coordinates are stored in the database of the type polygon. However when I check the database, I find GEOMETRY - 120B under polygon field. What does ...
6
votes
4answers
5k views

How do I convert a polygon into a point?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)