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.

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1
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1answer
231 views

postgis: cluster/group points based on distance

We have a set of thousands of points and want to group all of those which are within 100m distance from each other (to get the centroid from each group). A first idea was to build 100m buffers around ...
3
votes
4answers
224 views

Is there a way of auto_increment for the ID column in QGIS

I'm creating a fictive map and so I need to create lots of points, lines and for sure polygons. Later on I export my data as geojson. But before that I aways have to go and give every element an ...
4
votes
3answers
631 views

How to subtract polygons from polygon?

I have two polygon layers, one is green that represents all non-public right-of-way land. I have another polygon that is just a circle with a specified radius. I would like my output to be a polygon ...
0
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0answers
40 views

ClipRaster Class of DotSpatial is problematic

I want to clip a raster data with a polygon extent. Here is my Layers. Polygon layer is colored and raster is black and white. When I cliped using ...
4
votes
1answer
5k views

Create point in intersections of two layers

I have two layers. One of them is 'Road_line' and another one is 'forest_shape'. I want to create a point layer that has points in intersection of that layers. I couldn't find any tools for it.
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2answers
247 views

How do I json_encode without those quotes for the coordinates in leaflet geojson polygon?

I have a field name: 'coordinates' I have the coordinates stored in there: like this: [[ [100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0] ]] when I json_encode($geojson); I get ...
0
votes
1answer
63 views

How to avoid 'join features by location' for polygon to polygon creating extra areas

I am trying to work out which large polygons contain smaller ones within them in QGIS. I have a set of smaller features already defined (dark green below). However, for those smaller areas which sit ...
0
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0answers
28 views

Stack profile - polyline length

I have created a polyline that stretches from one side of a beach to the other (vertically). I have lidar data for 2005 and 2013. I am trying to compare the changes in morphology of the beach from ...
0
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1answer
60 views

Create polygons from point dataset, where each polygon contains 3 points from the dataset

I'm using qgis Brighton I have a dataset of 1500 points. I want to create polygons, where each polygon contains n=3 points from the dataset. The aim of this is to have clusters of 3 points, which ...
1
vote
1answer
102 views

Overlapping polygons in the same layer

I am working in QGIS on a vector layer where areas are classified using an attribute "typo". The problem I'm encountering is that many polygons are duplicated or overlapping, with the result that some ...
1
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0answers
44 views

Is it better to work with non-contiguous or contiguous polygons?

I would like to find width-height of a non-contiguous polygon in order to draw paths within it. My question: Is it better to use a bounding box (contiguous polygon) and then clip keeping my real area ...
1
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2answers
102 views

Intersection point of polygon and the line created by two points ArcPy

I have polygon layer. I selected the most distant vertex from centroid (picture: point A). (How to do that is in the answer here: Select the most distant vertex from polygon's centroid using ...
0
votes
0answers
23 views

Drawing polygon with predetermined area

Is there an option in quantum gis to draw a polygon with the specyfied area and is it possible to display dynamically the area when reshaping the shape of the polygon ?
1
vote
1answer
29 views

Is there any way to know if a polygon is part of another bigger polygon(s) in SQL server?

Basicaly, what I am trying to do is we have a lot of geographical containers like territories, sub-territories etc. and the boundaries of each keep on changing all the times and I have to store the ...
0
votes
2answers
64 views

Intersection between line and polygon

I have 2 layers in openlayers: first is parcel layer (polygons) and second is railway layer (lines). They are already drawn and all i need to do is when i click on some line, to get intersection of ...
2
votes
1answer
85 views

Simplify a polygon dataset with a minimum distance between the new vertices

I would like to simplify a polygon shapefile where the resulting output has a minimum distance of 5 kilometres between the new vertices. We have ArcMap 10 on an ArcView license, FME and QGIS. I have ...
4
votes
3answers
135 views

Select the most distant vertex from polygon's centroid using ArcPy

I have a poligon and the polygon's centroid. I want to select the most distant vertex from centroid (picture: point A). I used arcpy.FeatureVerticesToPoints_management to create a feature class ...
1
vote
2answers
327 views

How to shift polygons by updating their details in R

I have two polygon shapefiles and I want to see to what extent the observed amount of overlap is due to chance. I'd like to randomly move the polygons in one shapefile to new locations, measure the ...
1
vote
0answers
31 views

Calculate Sum on One Field Within Several Different Point Feature Classes?

I have several point feature classes (eg: the location of mall, liquor stores, etc), that I need to get the count of within a specified city district. Basically, I want to great a modelbuilder model ...
5
votes
2answers
85 views

Why does qgis give multiple centroids per polygon?

I have a shapefile for the boundaries of European NUTS regions, and I would like to compute the centroid for each of those regions. When I do this in QGIS (2.6.1 on OSX, using polygon centroids from ...
1
vote
2answers
76 views

How to separate polygons within layer and measure line through each polygon?

I have 3 layers of polygons, each layer with multiple polygons spatially separated, although the layer only counts it as 1 polygon. I have a layer with a line going through these polygons. What is ...
2
votes
1answer
95 views

Is there a way to give the drawing red polygon a higher alpha channel

Is it possible to set the alpha channel a bit higher when drawing? I don't mean the alphachannel of a already finished polygon, that's possible for sure! I mean the red area. It's really stressful ...
0
votes
1answer
56 views

Merge two points of two different polygons to get one polygon at the end

I would like to join points from two different features. I already searched for plugins but so far but didn't find one working plugin or solution for my task. So here is a picture of 2 ...
4
votes
1answer
426 views

Sub-dividing a polygon into smaller polygons

In OpenStreetMap data, some large areas are tagged with a residential=yes tag. Actually within this large polygon there are multiple smaller (rectangular) houses (which are actually not drawn as yet). ...
0
votes
0answers
35 views

line features show up as polygons in GeoServer

the layers are located in a postgreSQL Enterprise Geodatabase. I created a new line feature class and added it to the database and then added it to geoserver. But in geoserver it comes in as a polygon ...
2
votes
1answer
46 views

Is there a way to disable right-click in QGIS when drawing

I would like to know if I can disable the rightclick in QGIS. The issue is that I draw polygons that are kind of big, let's say 4000 polygon points. And as you know rightclick brakes the drawing ...
8
votes
3answers
2k views

Creating regularly spaced, defined # of points within polygon in QGIS

I used the research tool "Regular Points" to produce a certain number of points within a polygon, but it forms a rectangular grid of points rather than only within the shape of the polygon. Since I ...
2
votes
1answer
926 views

How to convert a polygon to a grid of polygons using QGIS?

For example, the city of Rotterdam represented as a hexagonal grid.
6
votes
2answers
112 views

POSTGIS get the max length of the polygon and the average width

I have in postgis a polygon type table. I need to calculate automatically the maximum length of the polygon: And the second one is the average width: I am doubting rigth now if this is possible ...
1
vote
0answers
60 views

Merge zip code based polygons to create sales territories

I have access the full data set of the KML file shown here: http://www.maptechnica.com/downloads/samples/mt_2014a_kml_us_zcta5_sample.tar.gz Here's what it basically looks like: ...
0
votes
1answer
69 views

Converting polyline data to polygons?

I am trying to convert some polyline coastline data into a polygon that I can use to clip/subset back other data sets by this polygon. There are some small gaps in the coastline data, which ...
6
votes
2answers
6k views

Create a polygon layer from point data

I'm currently using QGIS 1.8.0 I would like to create a polygon layer from a point dataset, where the size of the polygons relates to the resolution of the grid reference. The ultimate aim would be ...
0
votes
0answers
75 views

Is it possible to calculate area of polygons from GPS points without POSTGIS

I am new with GIS. Assume we use the UTM30N coordinate system. Is it possible to calculate an area (say a square box) by the 4 given points? (assume the points are in order, and the coordinates are ...
6
votes
5answers
3k views

Easy way to create a boundary polygon shapefile from a set of LAS files using ArcGIS 10?

I have a bunch of LAS file sets that I need to process. The current task at hand is to generate a "footprint" shapefile that contains polygons for each LAS tile. I am looking for a graceful way to ...
2
votes
2answers
290 views

How to count point shp inside polygon shp using Python?

This is my first time here, so I'll try to be as specific as I can. What I'm trying to do is found out which polygon contains the most points and write the result in a text file. Here is my script : ...
1
vote
0answers
26 views

Select a polygon which is just partly member of another polygon with its area of the other polygon

I need to generate random points within geometries, which works quite good, but there are some small errors. Take the picture below. There are some greenish and redish Polygons(?!) which do not have ...
0
votes
1answer
84 views

.net arcobjects draw polygon(rectangle) can not start at the preferred location

I am using the sample code (draw a polygon on the screen) provided by Esri but it seems I cannot start the drawing from a location I want, every time it starts at wherever the function(or tool) ...
1
vote
0answers
27 views

combine multiple geojsons

I have several geojsons which contain polygons. But the polygons are reaching over other geojsons. When I import them into lets say Qgis, the polygons, which are distributed among several geojsons are ...
2
votes
2answers
117 views

OGR DXF Closed Polyline Conversion

I'm trying to convert closed polylines into polygons using ogr2ogr from dxf to mssql. Here It says that polylines are converted into POLYGON if they are closed, but I always get the type LINESTRING ...
4
votes
1answer
835 views

How to find markers in selected dragbox openlayers 3?

Here is a part of code, draw = new ol.interaction.DragBox({ /* dragbox interaction is active only if alt key is pressed */ condition: ol.events.condition.altKeyOnly, ...
0
votes
1answer
228 views

Polygon grid shape file for landmass

I am interested in generating a polygon grid shape file for the landmass of the world. What I have presently is two tables in postgreSQL. Table 1: Coastal area shapefile ...
2
votes
1answer
57 views

Error converting a raster to polygons

When I am converting a raster using the polygonize tool, I get this error: ERROR 4: 'C:/Users/Vitor/Desktop/Cartografia EE_Portimo/COS RASTER/cos_raster_reeditada.tif' does not exist in the file ...
3
votes
1answer
920 views

How to perform a true GIS clip of polygons layer using a polygon layer in R?

I would like to do a true GIS Clip in R of soils polygons using a series of single boundary polygons, but I cannot find an R function to properly do it. It should work just like the CLIP function in ...
0
votes
0answers
111 views

Polygon dynamic grid creation for a shape file

I have used QGIS Vector->ResearchTools-> Vector Grid to create a 1lat x 1 long grid for the landpolygon shape file (from osm). Now, I am interested in creating dynamic grid for the original ...
2
votes
0answers
68 views

R Spatial: Trouble with disjointed polygon that has self-intersections

I have a shapefile which represents the areas of a city which have higher risks of flooding than others. This is a spatial polygon object however the polygon is disjoint and not connected. I also have ...
1
vote
2answers
203 views

Integrate grid and polygon of municipalities keeping the biggest municipality per cell with QGIS (or another)

I have a 9x9 grid and a polygon of municipalities of an extensive area of Brazil. My goal is to have a field indicating the biggest municipality per grid cell. I've been trying with intercept without ...
0
votes
1answer
72 views

Testing correlation between two polygon features

I am working on a project looking at county boundaries for the state of California. I have 2 polygon datasets with this same geographic boundary, and these datasets, when mapped individually, visually ...
1
vote
2answers
54 views

postgis - get nth point of a polygon

I would like to create a postgresql function to correct geographic coordinates inside a polygon that are outside the -180 to 180 range of longitudes. To do this, I thought I would create a function ...
4
votes
1answer
3k views

Joining polygons in R

I am wondering how to join spatial polygons using R code? I'm working with census data where certain areas change over time and I wish to join the polygons and the corresponding data and simply ...
0
votes
1answer
31 views