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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1answer
132 views

CAD line drawing to GIS polygons

I'm a (reasonably) proficient GIS user (mostly QGIS, but some Arc GIS) who has been thrown the conundrum of converting/importing CAD urban planning drawings (2D drawings produce in AutoCAD 2014) to ...
0
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0answers
84 views

polygon shapefile R extract issues

I'm trying to do simple RF classification in R based on https://gis.stackexchange.com/a/39103/48810. The code I am using is as follows: require(sp) require(rgdal) require(raster) ...
2
votes
1answer
118 views

Polygon centroid coordinates update error

After a week of unsuccessful fighting I'm forced to ask for your help. I have created a table 't_excavations' with fields 'id_excavation', 'geom' (MULTIPOLYGONE), 'longitude', 'latitude' CREATE ...
0
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0answers
44 views

Overlay polygons on raster in different projections

I'm overlaying polygons on a raster to get the average value inside the polygon (using SAGA->Shapes-Grid->Add grid values to shapes in the QGIS Processing Toolbox), using a geographic and a ...
1
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1answer
61 views

Connecting polygon accidentally deleted - filling in the gap

New QGIS user, Brighton 2.6. I accidentally deleted an elongated (lots of "peninsulas" polygon that represents a stream-based habitat - two gaps on SW boundary and two on the northern boundary ...
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1answer
120 views

QGIS: How to add a second polygon that is exactly 5km larger in all directions?

Given is a map with an airport. Within a distance of 5km around the runway there is a so called no fly zone for drones (in Switzerland). I want to show this zone in a map. What I would like to do is ...
0
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1answer
59 views

Simplifying polygons in ArcGIS considering contains-one-point topology rule?

I want to simplify polygons using the "Simplify Polygon (Cartography)" tool in ArcGIS 10.2. Additionaly there is one point in each polygon and this condition should still be fulfilled after ...
0
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0answers
47 views

Showing large number of polygons in SpatiaLite on Android map?

I have 2,300 complex multipolygon features in an offline SpatiaLite database. How can I show them on an Android map without slowing the map to a halt?
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2answers
282 views

Determine which points are contained inside a given polygon

I have these database tables defined: CREATE TABLE regions ( id SERIAL PRIMARY KEY, name VARCHAR(150) NOT NULL ) CREATE TABLE region_points ( id SERIAL PRIMARY KEY, region_id SERIAL ...
0
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1answer
91 views

Difference between a region and a polygon (mapinfo pro 12)

I am new to using MapInfo and have recently noticed the convert to regions and convert to polygon (edit: convert to polyline) function. What is the difference between a region and a polygon? Also, ...
0
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1answer
92 views

Clip multipatch to polygon ArcToolBox

I have a multipatch dataset and a 2d polygon. Which ESRI tool can I use to select only those multipatches whoms x,y are inside the polygon? Basically I want to select all multipatch features that ...
2
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0answers
57 views

Create polygons from many small. Expand to include space between

I'm just a programmer without GIS-skills as such. Hence this question: Intro: I have a lot of polygons; actually each private-owned real estate in my country. I also have "counties" as polygons. ...
1
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1answer
98 views

how to find that two polygon boundaries are connected?

I am working on a Geo database where there is a layer with many polygons. i want to find that which polygons boundaries are connected so that i can create new layer from that polygons and which ...
1
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0answers
85 views

Create diagonals in polygon with QGIS or ArcGIS

How is it possible to create the diagonals in/of polygons and to calculate the length of this diagonals afterwards. It's for a lot of polygons so maybe a fast/automatic method would be nice. I ...
1
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1answer
40 views

Enlarging polygons in a kml file

I have a KML file containing several hundreds of Polygon all around the globe, projected in lat/lon WGS84, decimal degrees. I need to enlarge all the polygons adding 23km at the top and at the bottom ...
2
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1answer
60 views

QGIS - Label outside polygon

is it possible to place a label automatically outside its polygon? Marcus
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0answers
33 views

Bulk geocoded data of historic empires / countries of the world?

Is there an open dataset (of the likes of Pleidas) which provides geojson data (or similiar) of empires / areas of the world? There was a similar question here (link), however, I am looking for a ...
0
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2answers
115 views

How to calculate a set of minimum bounding boxes for a polygon

I need to calculate a set of minimum bounding boxes for a polygon. Id est having a complex polygon I want to envelope it with a set of small boxes instead of a big one.
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1answer
374 views

calculate the population inside a buffer with census data

I have population data matched with polygons and a set of points that I have drawn buffers around. Assuming that the population within each geographical area, i.e. the polygons, is evenly distributed, ...
0
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0answers
125 views

Raster to polygon with RGB composite using Arcgis

I am trying to convert an RGB composite to a shapefile to use with. The raster to polygon function returns with three shapefiles with "grid_code" of the value of each of these three channels. I am ...
0
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0answers
40 views

What replaces SQLserver SqlGeometryBuilder, for Windows store apps?

Porting Visual Studio 2008 C# application to Visual Studio 2013, Windows 8.1 store\phone app (need to include DB with the application). What DB to use (coding in c#), to replace this code, not sure ...
0
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0answers
42 views

Parcels management and land ownership

Is it possible for me to split a feature by the column area i input?Like A feature has 3000 sqm and i have in attribute table column 1= 2000sqm and column 2= 1000 sqm and based on this 2 colums to ...
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1answer
235 views

QGIS-->rotate polygon by a numeric value

Is there any way to rotate a polygon or a feature by entering a numeric value in QGIS thx
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1answer
66 views

How to copy a line from polygon to an other polygon QGIS 2.6.1

I have a polygon(state) now the state divide into two. I have a new polygon with two state. I want to copy only the new border(line) which divides the two state from new polygon to old. I am ...
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2answers
225 views

Single polygon shapefile to multiple polygon shapefiles [duplicate]

I created a single shapefile that contains multiple polygons by selection by location of the route I had and the ESRI USA counties polygon layer to give me the counties that were in the area I was ...
5
votes
2answers
142 views

Calculating edge length of polygon within overlapping polygon

I have a layer of wetland polygons and a layer of lakes. I basically want to find the total length of lake shoreline contained within each wetland and add these values as an attribute of the wetlands. ...
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2answers
118 views

Multiple polygon to shapefile in XYZ format

I have an array of gridded data in XYZ format. I am trying to write shapefile (*.shp) file with multiple polygons with the pyshp python libraries. I am able to make it for only one polygon with the ...
6
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1answer
117 views

What do you call this non-hole edge condition?

After generalizing or simplifying polygons, you often get legitimate holes in polygons, which are separate parts and can be filled. But what is the correct term for this triangular shape? It is an ...
1
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1answer
49 views

Why is my map zoomed in so ragged compared to what I actually drawed in QGIS

So overall my map looks the same like what I draw in QGIS. The issue is that when I zoom in, in that case 54x then you can see ragged lines. QGIS Browser That is not what I need. I need high ...
1
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2answers
95 views

How to get the number of polygons of a geometry in PostgreSQL

How can I get the number of polygons that form a geometry in PostgreSQL? For example U.S map has a lot of islands in addition to its main lands. I want to count these islands plus the main lands.
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28 views

How can I redistribute points within a polygon using certain criteria in ArcGIS?

I have some points (representing pharmacies) scattered around my research area and I would like to redistribute those points through the area using the following criteria: The points should ...
1
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1answer
74 views

How to create Spatial Reference System in QGIS?

I have some Attribute and the coordinate and the coordinate reference system. I want to create a DBmanagamet form my spatial data. To do that I want to create one table with name Spa_ref_sys, but I ...
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0answers
19 views

QGIS - Label polygon with different projections

I have a polygon layer projected in an UTM. In properties I checked 'show all labels for this layer'. Does anyone know why the label does not show until zoom 15:1 in QGIS with CRS-4326, while in ...
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2answers
86 views

Using GDAL to get vertices of a multipolygon

I am successfully using GDAL to get the vertices of a polygon from a ShapeFile using .NET code. This link showed me how to do that: ...
0
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0answers
309 views

Polygon of Voronoi cell using scipy.spatial?

I have points (e.g., lat, lon pairs of cell tower locations) and I need to get the polygon of the Voronoi cells they form. from scipy.spatial import Voronoi tower = [[ 24.686 , 46.7081], [ ...
1
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0answers
90 views

Inflating the boundaries created with convex hull

I have a set of lan and lat points and have plotterd a convex hull for them using QGIS. A polygon is created along the set of points and plotting them on the MAP. Now I am trying to inflate the size ...
6
votes
1answer
417 views

How to compute Straight Skeletons using Python?

Is there a Python package which provides an implementation of a Straight Skeleton algorithm? I'm aware that the open source (C++) project CGALcontains an implementation but it seems like ...
-1
votes
1answer
56 views

Partitioning Polygons layer to smaller partitions

I Have a huge polygon layer which contains many thousand polygons> i am going to operate an intersect loop for every point in the layer with near polygons. i use ITopologicalOperator op = ...
2
votes
1answer
246 views

Split polygon into several smaller polygons in QGIS

I have a layer of polygons depicting response boundaries, I would like to break each of these polygons into a number of sub-polygons. As this is for an exploratory project, the polygons themselves ...
2
votes
2answers
128 views

ArcGIS lines to polygons without holes

I have a dataset with contours. Depression contours are separate of the normal contours and need to be digitized counter-clockwise. Still, there are usually some faulty ones with wrong direction and ...
0
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0answers
83 views

Polygon vertex “duplication” in QGIS?

New QGIS user, Brighton 2.5. When creating or moving new vertex points of a recently-cut polygon (hence adjacent polygons) I get "duplicate" or "criss-crossed" lines beneath the former vertex ...
2
votes
0answers
72 views

Polygon Layer Cleaning with QGIS

I have a little situation with my data. I have vectorized a raster layer, and now I have some issues with the geometries, as you can see in the picture. Most of errors I have are like this one. ...
1
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0answers
46 views

merge polygons of single feature QGIS

I am new to QGIS and have done some research on this topic before posting but not sure I found an answer. I have one feature that has multiple polygons (islands of a nation). In reality, there is ...
2
votes
1answer
306 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 ...
0
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0answers
59 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 ...
1
vote
1answer
45 views

Edit existing Polygons to include several new nodes

I want to define catchments which are quite large from vector contour data. I normally start zoomed out to define the catchment generally as it is easier to see. I then zoom in and refine the ...
0
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0answers
36 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
66 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
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0answers
45 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 ...
0
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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 ?