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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3
votes
4answers
2k views

Clip a raster using a shapefile into multiple rasters?

I have a raster file representing a large area and a shapefile of 30 polygons representing watersheds. I would like to clip the raster with the shapefile to create 30 rasters representing each ...
1
vote
1answer
39 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 ...
1
vote
1answer
86 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 ...
2
votes
0answers
51 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. ...
2
votes
1answer
58 views

QGIS - Label outside polygon

is it possible to place a label automatically outside its polygon? Marcus
6
votes
1answer
394 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 ...
0
votes
0answers
31 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
votes
2answers
109 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.
1
vote
1answer
300 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
votes
0answers
96 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 ...
3
votes
3answers
625 views

How to clean up a polygon by removing vertices and lines within?

After merging a set of shapefiles I've ended up with polygons that have vertices and lines within them. Is there a simple tool to remove these vertices and clean the polygon in ArcMap 10.2? I realise ...
1
vote
1answer
179 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
1
vote
2answers
107 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 ...
0
votes
0answers
37 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
votes
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 ...
1
vote
2answers
190 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 ...
1
vote
1answer
62 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 ...
5
votes
2answers
131 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. ...
1
vote
1answer
62 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 ...
6
votes
1answer
112 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
vote
1answer
164 views

Smoothly interpolating Polygons from set of coordinates?

I'm still quite new to QGIS and I'm using it to display and analyze my soil data. I have point information on the distribution of the soils in a specific area and I need to create a soil map from ...
1
vote
1answer
48 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
vote
2answers
81 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.
2
votes
4answers
776 views

Combining different geometry types into same feature class?

I've searched the question in this blog. Maybe I don't use the right words but anyway my problem is not present in any post so I'll try to explain my question by opening a new one. I have a polygon ...
0
votes
0answers
26 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 ...
0
votes
1answer
78 views

How to transform isolines to isopolygons with postgis?

I have a table a postgis table of isolines that's defined like this: CREATE TABLE myisolines ( gid serial NOT NULL, isotime timestamp without timezone, val numeric(10,4), geom ...
1
vote
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 ...
0
votes
0answers
75 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 ...
0
votes
0answers
253 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
vote
0answers
82 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 ...
-1
votes
1answer
51 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 = ...
6
votes
4answers
758 views

Exporting polygon features to individual image pngs

I have a shapefile with a few thousand polygons, ArcGIS [9.3] (and even PostGIS). I would like to export each of those polygons into its own thumbnail image file without any real context. What is the ...
2
votes
0answers
64 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. ...
7
votes
2answers
4k views

How to create a heat map or density map from stacked polygons in ArcMap 10

I have a polygon shape file that has many overlapping features. Each feature represents an area used by polar bears. So some of the polygons overlap and some don't, and there are separate clusters of ...
2
votes
2answers
120 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 ...
1
vote
0answers
44 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 ...
1
vote
2answers
115 views

Extracting/Exporting coordinates from polygons (shape) to text?

Is there any well working way to extract the X and Y coordinates of a polygon from shapefile to some sort of text (preferably csv)? The whole process should be somehow done automated through a ...
2
votes
3answers
197 views

Summarize the total area of land use polygons within map sheets - how?

I would imagine that at least some of you have encountered similar problems to mine and I´d like to hear how you solved them. I have a map sheet index (a grid as a shape file) covering a large area. ...
1
vote
1answer
39 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 ...
2
votes
1answer
275 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
309 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
792 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
votes
0answers
53 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.
0
votes
2answers
333 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
66 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
votes
0answers
33 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
votes
1answer
63 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
133 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
vote
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 ...