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
0answers
21 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
90 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 ...
4
votes
3answers
84 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
0answers
13 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:
...
4
votes
1answer
55 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 ...
2
votes
0answers
26 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 ...
5
votes
2answers
99 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 ...
1
vote
0answers
30 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 ...
-1
votes
0answers
30 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 ...
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
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 ...
1
vote
2answers
74 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);
}
...
2
votes
3answers
48 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.
1
vote
1answer
34 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
56 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 ...
3
votes
2answers
62 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 ...
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 ...
0
votes
1answer
59 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
66 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
79 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 ...
1
vote
0answers
48 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 ...
3
votes
0answers
49 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 ...
0
votes
1answer
46 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
0answers
31 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
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
48 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
46 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
0answers
72 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 ...
2
votes
1answer
77 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 ...
0
votes
1answer
78 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 ...
2
votes
3answers
69 views
How to minimize the number of points in a polygon?
I'm building a web application that will be transferring polygons from server to client. Initially, the shapefile is coming from an external source that I have no control over.
Often, I find polygons ...
2
votes
1answer
53 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
51 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
71 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
42 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
20 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
55 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
60 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
61 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
145 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
48 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
43 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
94 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
30 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
39 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
213 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
64 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
168 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
0answers
38 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 ...
