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.
0
votes
2answers
24 views
How to scale/reduce my polygon without changing the central lat & long?
I am writing a VBA code to resize my polygon, I get a input as vector points(Shape file). The code below resizes it as according to my scale factor but my central latitude and longitude are also ...
4
votes
1answer
95 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
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 ...
0
votes
2answers
25 views
Zooming into a particular polygon
I am getting the polygon id by doing
identifyParams.geometry = evt.mapPoint;
identifyParams.mapExtent = map.extent;
identifyTask.execute(identifyParams, function(result) {
var i;
var ...
3
votes
2answers
47 views
“GIS” Mapping on Monument - Scaling
I have a Baroque tombstone for which I have to map the damage phenoma. Normally one can use a vector drawing programm but one has always two boundaries between the different polygons. Questions:
Is it ...
1
vote
2answers
102 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 ...
3
votes
1answer
59 views
Masking/removing polygons from shapefile
I have a shapefile containing the road traffic noise of a city.
The shapefile has 5 columns, where 'noise_in' (noise interval) ranging from 1-5 is included.
I want to remove/mask the road noise from ...
3
votes
0answers
77 views
Problems converting polygon to point
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
0answers
53 views
Are polygons created in Arcpy built in any order?
My script uses a search cursor to evaluate polyline coordinates and build polygons based on those coordinates. The script works well, but I am curious as to whether anyone knows the order (if there ...
14
votes
2answers
758 views
Is it possible to gray out a Google Maps map except for some area?
What i am looking for is a way to emphasize a certain area on a Google Maps map by graying out the rest of the world.
I heard about some solution of using 2 polygons of which 1 is visible and the ...
1
vote
1answer
340 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
0answers
34 views
polygon/raster intersection artifacts
I'm intesecting a polygon with a raster using PostGIS > 2.0. The outer boundary of the polygon is formed by the convex hull of polygons (building outlines plus safety margin) and the inner rings are ...
8
votes
1answer
101 views
How to automatically reduce polygon size?
I am working with two polygon layers (counties & states) which I will 'intersect' to find which counties are within which states.
Due to data inaccuracies I have to change all county polygons and ...
5
votes
2answers
115 views
inner convex-hulls in a set of 2D points
A set of 2D Points are scattered randomly (i.e., no specified pattern), we are interested in finding all inner-convex-hulls (ICH) in an order of largest in area to a minimum until the entire study ...
5
votes
3answers
95 views
How to insert a GeoJSON polygon into a PostGIS table?
I need to insert a polygon from GeoJSON to my PostGIS table. This is how the SQL query looks like.
INSERT INTO tablename (name, polygon)
VALUES
(
'Name',
ST_GeomFromGeoJSON
(
{
...
0
votes
1answer
82 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 ...
0
votes
0answers
15 views
How to obtain a region polygon from Google Places Autocomplete
I am trying to use google places autocomplete to search for a place, get its polygon region from mapques/nominatim and render the result in google maps.
Here is where I am having difficulties:
...
5
votes
3answers
375 views
How do I use polygons to apply a unique value to all raster cells within those polygons?
In ArcGIS 9.3, I have a raster file that I would like to "mask" with polygons, giving a single value to all the raster cells that overlap the polygons. How can I do this? Here's a screen shot, where ...
5
votes
1answer
75 views
Tips for minimizing shapefile size without compromising geographical detail?
I work for a state government's fisheries service, and lately we've been digitizing a lot of our regulatory boundaries within the state's waters that we'd like to service out on web maps. ...
4
votes
1answer
56 views
Raster to vector with gaps in Landsat ETM
I need to find size of water area from a raster (jpg) using QGIS 1.8.0-Lisboa. The raster is a Landsat image with gaps of data in it.
I used Polygonize, but the output file shows wrong polygon size ...
1
vote
0answers
32 views
Point Within, Query in a buffer polygon in WMS like in ArcGIS ESRI
I need to do a query to filter the result inside a polygon or geometry, like this:
http://help.arcgis.com/en/webapi/javascript/arcgis/jssamples/query_buffer.html
But, i need to do this in a opengeo ...
2
votes
0answers
30 views
Clipped raster leaks outside polygons
I am trying to clip a raster (DEM) with a polygon layer in ArcGIS10.1, using Data Management>>Raster>>Clip. Basically the clipped raster has many pixels outside the polygon boundary, mainly for thin ...
-1
votes
0answers
32 views
polygonal join in ArcMap 10 (no need for attributes)
I have two large polygonal layers I am trying to join together. There are many polygons that are not overlapping and keeping the attributes between the two is not a priority. Any suggestions for ...
3
votes
1answer
686 views
Polygon to Raster Tool Problem
I am trying to create a raster data set from county level polygon data for the US. I have successfully created one raster from a dataset, but when attempting another, it does not work. I am ...
1
vote
1answer
39 views
Polygon to fill gap
Using postgis I want to fill a gap between other polygons.
Can you help with some directions what functions to use ?
Thank you and sorry if the question is rather noobish.
Image to explain from ...
0
votes
1answer
49 views
OpenLayers generate random polygon
I have a world map. I need randomly to generate polygons and render them on map.
I have no problem with rendering, but can anybody suggest how to generate polygons with random geometry? (I need n ...
0
votes
1answer
64 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 ...
2
votes
1answer
145 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
...
1
vote
2answers
83 views
How to add a polygon from GeoJson into Leaflet?
I try to use the following function to add polygons to my Leaflet map.
function polygon(geojson)
{
alert(geojson); // alert for testing
layer = L.geoJson(geojson);
layer.addTo(map);
}
...
0
votes
2answers
29 views
Field within a Field - Donut Parcel?
Firstly, apologies as I'm a newbie and have only been studying GIS for a few months.
I am digitising field boundaries and have a field within a field, and am wondering what the best way of ...
3
votes
2answers
68 views
How to computational efficiently check if there are any overlapping polygons in a group of polygons?
I need to do some processing with groups of polygons. If any of the polygons in the group overlaps other polygon the result is unpredictable and don't throw any error. So, I need to detect if there is ...
2
votes
3answers
51 views
How to divide a polygon with another polygon
I am working in ARCMAP 10.
I am trying to divide a polygon with another polygon. I don´t want to clip any part away, but only divide the polygon?
The polygons are stored in two different layers.
3
votes
1answer
70 views
digitizing (tolerence) error in line data
I have designed a large number of boundaries. For accuracy, I took lines in patches from different data sets and merged them into one. Now I want to turn them into polygons from lines. I every second ...
1
vote
1answer
39 views
How to get polygons from PostGIS table to PHP array best?
Currently I fetch polygons from a database table using ST_AsText(). The results are in text format, like the following.
POLYGON((84 104,212 48,321 122,243 179,275 238,131 240,84 104))
I am not ...
0
votes
2answers
58 views
Find and list all polygons that overlap with another polygon
I am working with two polygon layers which overlap but are unrelated (one is congressional district boundaries, the other is MPO area boundaries).
I would like to generate a list of all the ...
7
votes
1answer
210 views
How to rectify polygon-shapes in Quantum-GIS? [duplicate]
I have some polygon-shapes in qgis-1.7.0 and want to ensure that every polygon is a rectangle. See image below.
Is there any way I can do this in quantum-gis (or any other f/oss)? Or how can I ...
0
votes
2answers
55 views
Cannot insert simple geometry data
I installed PostgreSQL 9.2.4 and PostGIS 2.0.3 on my Windows 8 machine. Then I created a table using phpPgAdmin and added a geometry column using the following statement.
SELECT ...
2
votes
2answers
63 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 ...
1
vote
4answers
173 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
63 views
Merge attribute of points into a polygon : Arcmap 10
I have points layer which the attribute looks like this:
FID Shape ID Lat Long
0 Point 2065 -5.51666 106.48333
1 Point 2319 21.93333 120.73366
I also have polygons layer :
FID Shape ...
1
vote
3answers
70 views
Openlayers vector feature coordinates are not transforming,
I have a OpenLayers vector with a single feature [0]. It's coordinates are in the map projection (EPSG:3413) and I want them in WGS84 (EPSG:4326) decimal degrees. I have the following code which ...
5
votes
0answers
81 views
How to find the maximum-area-rectangle inside a convex polygon?
In this post we are looking for algorithms / ideas on how to find the maximum-area-rectangle inside a convex polygon.
In the following figure, numbers are the areas of the fitted rectangles. As shown ...
7
votes
4answers
8k views
Extract coordinates of polygon vertices in ArcMap 10?
I've got about a dozen polygons in a feature class loaded in ArcMap 10, all in geographic WGS 1984.
How do I easily obtain the coordinates associated with each vertex of each polygon in that feature ...
0
votes
0answers
32 views
QGIS GPS live tracking adding polygon vertices
Maybe I'm missing something or maybe it is a bug? I'm trying to add polygons using the GPS information console. The only button available to record data is "add polygon", but if you click on it, you ...
3
votes
1answer
383 views
How do you convert raster to polygon while avoiding small polygons
I intend to convert a raster to several polygons, but I want to ignore too small polygons, and just keep larger polygon. How can I do that?
Thanks in advance!
3
votes
1answer
37 views
How can I check if a multipolygon can be represented as a simple polygon?
I have a large (30m+ records) spatial data set I have imported into a PostGIS database. I did not expect to find multipolygons in the data set, but it does have a few of them. I'd like to take a ...
2
votes
1answer
49 views
How to determine the longest side of a polygon in QGIS?
Is there a possibility to determine the longest side of a polygon with QGIS? As I need to do that for hundreds of polygons I would prefer an automized method (like a plugin).
So far my idea was:
...
1
vote
1answer
47 views
Polygon Nodes do not have separate coordinates [duplicate]
I'm attempting to measure the distance of a series of points from a smaller number of polygons. As a first step, I've changed the polygons into points along their border, via the
Vector> Geometry ...
2
votes
1answer
78 views
ArcGIS - merge polygons and get combined area
I cannot for the love of god figure out how to combine (join?) two overlapping polygons to determine the combined area they cover in ArcGIS 10. I am sure the Geoprocessing tools can do it, but just ...
2
votes
0answers
66 views
Cannot reselect polygon after modify
I've got various vector layers on a OL map.
On one layer I have a few draw controls. If I draw a polygon I can select it (the whole pop-up thing works). This also works for all the other features.
...
