On a map, a closed shape defined by a connected sequence of x,y coordinate pairs, where the first and last coordinate pair are the same and all other pairs are unique.
2
votes
1answer
64 views
Evaluate minimum points required to define polygons based on an error threshold
I need to build a model or write an algorithm to do this, which I would like you to share your ideas with me.
here is my cadastral problem: I have plenty of polygons and I need to make a report of ...
0
votes
0answers
73 views
Fill polygon with colour depending on the value in MS SQL Server table
I'm using QGIS 1.8. Windows 7. I have a table in MS SQL Server 2008 R2 database with two fields: id and density(int). There are several polygons in QGIS. How can I set color of polygion depending on ...
1
vote
0answers
88 views
Line to Polygon via Polygonizer in QGIS
My question is in the same vein as this one.
I'm attempting to convert precipitation lines (Precipitación Media Anual) to a polygon for Mexico in QGIS using the Polygonizer plugin.
After running the ...
0
votes
0answers
55 views
Offset a Polygon defined in Lat Lng points by a given distance of miles or km
I am trying apply a positive offset/buffer (enlarge a shape equally from the borders) to a polygon that is made up of a series of latitude/longitude coordinates by a distance that is defined in either ...
0
votes
0answers
22 views
query for adjacent polygons in GRASS?
i need to create a table of each district in india's adjacent districts.
i found this query but couldnt get it to work for me: SELECT p1.PK_UID, p1.Name FROM Polys p1, Polys p2 WHERE p2.PK_UID=1 AND ...
3
votes
1answer
67 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
65 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 ...
2
votes
2answers
82 views
How to make mapable geo data from a solid jpg/png
I have a bunch of hardiness zones, as you can see here: http://mangoly.herokuapp.com/workroom/googlemaps/zones/
They are solid colored PNG images. I know the geo coordinates of the bottom left hand ...
0
votes
1answer
187 views
How to draw straight lines inside google map polygon [closed]
I have created a google map using google map javascript API V3. I am drawing number of zipcode polygons. The polygons are of different colors depending upon some condition. Now I want to draw straight ...
0
votes
1answer
62 views
matching a border of one polygon to another [duplicate]
I have a polygon (A) that I drew the eastern border of in QGIS. I have another polygon(B) whose western border I want to nest against the eastern border of polygon a so they are touching but not ...
2
votes
0answers
50 views
Matching points in table to polygons
this is my first post to this forum. I hope to start participating actively.
I have a table with several records (aprox 200.000), each with its own coordinates. And I need to identify the "Polygon" ...
0
votes
1answer
102 views
How to label each polygon in a layer?
QGIS 1.8.0 Mac OS 10.6.8: I want to label each polygon in a layer in a similar way to this image (done in WP Presentations) and am totally confused by the manual. Obviously I have to find a list of ...
0
votes
0answers
30 views
How to determine if a line is within a polygon or if it exceeds the polygon boundaries?
So I have a polygon layer and a line layer and a point layer...
Each line goes to the centroid of 1 polygon, some of those lines come from within the same polygon, some come from outside of that ...
0
votes
0answers
36 views
Slicing / Cutting a Polygon / Polygon List based on another geometry
I currently use GeoDjango (GEOS, GDAL, PROJ4), I have rather medium set of polygon data (buildings).
To streamline them to a client efficiently (client has a limited viewport) I only want to send the ...
1
vote
0answers
48 views
graduated pattern polygon fill
I'm sure this question is really really basic but I appeal to you because I hate the idea that I have spent 20 minutes trying to do such a simple thing...
All I want to do is style a polygon layer by ...
4
votes
3answers
245 views
Convert multiple lines into single line
I've no idea if this is basic or what but I have this data that contains multiple lines (forming a polygon shape). I want to convert those lines (multiple - each with a start and end point) to a ...
2
votes
1answer
73 views
How to delete one polygon from a multi polygon record in a spatialite database using QGIS
I have a spatialite database with multi polygon records within the database. When i try to edit these records i cannot delete just one of the polgons for a specific record. It only allows me to delete ...
1
vote
4answers
209 views
Counting road intersections and blocks
I have a shp file that consists of the road system of Mexico City. I would like to count the number of road intersections (crossings) and blocks (which I would define as a segment starting from one ...
0
votes
1answer
56 views
Selecting a Polygon based on the location of a point
Currently I have a polygon layer made up of three shapes. All the shapes are listed in the attribute table. One of these three shapes intersects a point. I would like to select just the shape that has ...
7
votes
3answers
190 views
maximum circle inside an irregular polygon from a random point
I am trying to work out an algorithm for creating the maximum radius circle within an irregular polygon (a census tract) based on a given center of the circle.
The motivation for this is to obscure ...
4
votes
1answer
99 views
How to combine stacked polygons within a shapefile?
The image below shows my shp-file. Every polygon has the same transparent color. So a darker blue means, that several polygons are stacked! How do I cut every polygon with each other so no polygons ...
0
votes
2answers
77 views
Why is polygon used as range in GIS and maps?
I am enroute to create an app that finds nearest venues. I already have another SO question on this regard.
I don't have any experience with such features, and some of the concepts are not being very ...
0
votes
0answers
132 views
How to create polygon with DBGeography Class in Csharp
I want to create a polygon with csharp 4.5 via DBGeometry class.
I found example on csharp to create a point via System.Data.Spatial namespace. (Requires Reference System.Data.Entity)
This code is ...
0
votes
1answer
71 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
105 views
How to convert a shapefile polygon to raster in C#
Does anybody know a way to convert a polygon (vector) in a shapefile to raster data WITHOUT using ArcGIS Explorer Desktop? Is there a way to do this 'progmatically' in C# (WPF with ArcGIS runtime ...
0
votes
0answers
11 views
Assigning an area to a geoprocessed polygon [duplicate]
using QGIS
I've geoprocessed a layer using the difference function but the newly created layer still holds the area attributes of the layer I used as the input layer...
ie on my output layer, a tiny ...
1
vote
2answers
106 views
Using the ArcGIS Runtime SDK for C# is there a method to Hit Test for a polygon on the graphics layer?
I am very new to using ArcGIS runtime SDK for C#.
I have loaded a polygon from a shapefile.
I wish to query if a lat/long point is inside or outside the polygon?
How can I do this?
Thanks in ...
2
votes
1answer
162 views
Create a square grid polygon shapefile with python
i have the following coordinates
minx,maxx,miny,maxy = 448262.080078, 450360.750122, 6262492.020081, 6262938.950073
i wish to create a square grid of size 1 m using python.
import math
...
2
votes
1answer
141 views
Convex Quadrilateral Polygons subdivision in equal parts using Python / OGR
Consider an irregular polygon (P) which has four vertices.
I would like to subdivide P into smaller polygons as shown here http://i.stack.imgur.com/4SKhB.jpg
In the old days I was using ArcGIS 9.3 ...
2
votes
1answer
128 views
R: How can I create a polygon from several polygons and a line?
I have some spatial objects that I want to combine, namely three polygons and a line. The ultimate goal is to create a polygon that I can overlay on an area of a map of administrative divisions of the ...
3
votes
1answer
103 views
Polygon to Raster is taking longer in script than in arcmap
I have a large dataset that I am working with. Basically I have a table with 900,000 records that I join to a geodatabase feature layer, then convert that to a raster.
This process takes a total of ...
6
votes
1answer
50 views
Is there a way to select only a certain polygon for editing?
I have a spatialite data base with 4300 polygons contained within. I wish to be able to edit the polygons but once i have highlighted the Polygon from the attributes table i find it hard to edit the ...
1
vote
0answers
39 views
Avoid rounding of coordinates in pyQgis
If I get the coordinates of a polygon in qgis by
x = geom.asPolygon()
It rounds off the coordinate from i.e.
-27,200,334.86
to
-2.72003e+07
How can I avoid that?
4
votes
1answer
139 views
MongoDB: Search for polygons which have a certain location
Good day :).
I am trying to implement a search feature on MongoDB using Mongoose.js , the short version of which is this:
I tag locations on a map as polygons. and give them names. Then when an user ...
1
vote
0answers
60 views
Is segment of polyline contained in polygon
I am pretty new to arcpy and am slowly learning all its functions. I have a scenario where I am traversing a polyline. I get a start point and an end point on the polyline and form a segment with ...
3
votes
1answer
93 views
How to make survey lines within a polygon?
I am trying to figure out how to make survey lines within a polygon.
So first I make a polygon. Now I need to fill this polygon with lines, where I can choose the spacing between the lines, and the ...
11
votes
2answers
386 views
Creating Thiessen (Voronoi) polygons using lines (rather than points) as the input features?
I have a set of line features inside a particular polygonal boundary. For each line, I'd like to generate a polygon inside which every possible point is closer to the given line than to any other line ...
5
votes
2answers
114 views
Need an Algorithm to Determining Polygon Borders
I'm currently writing a program in Java and I'm dealing with polygon objects. I want to create a different color border between touching objects depending on their class (i.e. land, ocean, etc). I ...
1
vote
1answer
179 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
0answers
131 views
creating graphic polygon from extent in Arcgis JS API [closed]
I'm tryin to draw rectangle based on extent object. Could someone look trought my code and Tell me what am I doing wrong?
var polygon = {
"geometry" : {
"rings" : [[[extent.xmin, ...
2
votes
1answer
65 views
Remove intersect of one polygon from another in R
I am trying to remove the intersect from Poly2 onto Poly1. Below are the coords of the 2 polygons.
> coords1
[,1] [,2]
[1,] 992.0161 7462.531
[2,] 950.1962 7413.532
[3,] 902.3632 ...
1
vote
3answers
253 views
How to auto fill or delete sliver polygons without losing precision?
I am developing some boundaries in which precision holds the key value.
Using ArcGIS 9.3 I am converting lines to polygons using the "feature to polygon" tool. The lines are accurate but I find ...
2
votes
2answers
185 views
How to create a multipart polygon?
I have two polygons that consist of two separate polygons/lines in QGIS). How can I make this into a multipart polygon, which consists of 1 line in QGIS?
2
votes
1answer
462 views
How do i calculate line segment lengths within a polygon?
I have a layer with line segments and a layer of polygons (in this case, buffers around points). I need to create a new field for each polygon that contains the total length of all line segments ...
0
votes
1answer
147 views
Geojson multipolygon doesn't work with Leaflet bindPopup?
I have polygon and multipolygon data in Geojson format and when I try to bind popup for polygon, it works perfectly, and when I try to bind it for multipolygon, it doesn't work.
Is that some Leaflet ...
1
vote
0answers
27 views
Suggestions for vector format for polygons
I am using two polygon tables in postgis (A and B ).
I need to make a vector file that incorporates information of the overlapped polygons B intersecting each polygon on (A).
I can make a single ...
1
vote
0answers
52 views
When digitizing, objects are not saved well
I've some problems with digitizing.
If I draw a line or a polygon, the line or polygon is saved in the attribute list, but not visible and its location is not saved either (when I zoom to the object ...
1
vote
1answer
385 views
Calculate polygon area inside extent
We're using ArcMap 10.0 sp5, creating a tool in c# using the ArcObjects sdk.
Is there a built in function or simple set of steps that calculates the area of each feature of a polygon layer within a ...
0
votes
1answer
255 views
Calculate maximum and minimum elevation for a polygon layer from a DEM [duplicate]
I have a polygon layer and would like to know the min and max elevation within each polygon. My elevation layer is a digital elevation model. I'm not quite sure how to extract that information.
I am ...
0
votes
0answers
34 views
Where can I get polygons for the Municipalities of Puerto Rico?
I'd like to find GeoJSON files to draw the polygons of municipalities of Puerto Rico.
It might be nice get the Nokia Map (or any reasonable publicly available map) of the same regions and overlay ...
