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
18 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
5k 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
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0answers
18 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 ...
2
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2answers
24 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 ...
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 ...
0
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1answer
29 views

How to join point and polygon layers but retain polygon geometry for choropleth in ArcMap? [on hold]

background: I tried to join a point layer and a polygon layer so that I could make a choropleth map of the attributes in the point layer but all I can get is a point map regardless of which layer I ...
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2answers
44 views

Is there a way of auto_increment for the ID column

I'm creating a fictive map and so I need to create polygon after polygon. Later on I export my data as geojson. But before that I aways have to go and give every polygon a unique ID. I don't need a ...
2
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2answers
133 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
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1answer
113 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 ...
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0answers
14 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 ...
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1answer
22 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) ...
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0answers
13 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
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2answers
42 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
386 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, ...
1
vote
1answer
130 views

Is it possible to draw polygons along Google Maps Polyline?

Web application has option that user draws polyline on Google Map. After he draws it, there is a button 'Add polygons', which should draw polygons along that line, based on some width and height in ...
0
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1answer
199 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
101 views

Dynamically drawing a polygon around another shapefile, ArcGIS 10.2

Let's say I have a vegetation raster that indicates the density of forest all over the world. I also have a shapefile that contains the admin boundaries of each country in the world. The easy part is ...
2
votes
1answer
24 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 ...
2
votes
1answer
454 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 ...
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0answers
101 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
23 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
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2answers
187 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
31 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
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2answers
37 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
2k 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 ...
1
vote
1answer
134 views

autocad-map of real estates with own coordinate system and information to be converted to use it in QGIS

I have a question regarding CAD and QGIS, but unfortunately I don't have a clue of CAD. Here it goes: Real estates data has been mapped. There are several reference points surrounding the area. So ...
0
votes
1answer
23 views
1
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0answers
22 views

QGIS polygon - filling a polygon gap

I do not use Python, I'm afraid. I need to fill in a polygon gap for this map of Scotland. Here is the gap: How do I fill in this gap? I have already tried drawing another polygon inside the gap ...
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vote
2answers
16 views

how can we save vector layer as a file in openlayers

Im using mapserver + openlayer for GIS API and im new to GIS. I'm done with drawing line, point and polygon features in openlayer. but not being able to save it in some shapefile afterwards i got to ...
0
votes
2answers
193 views

Calculating minimum/maximum width for overlay of two polygon strips in ArcGIS or some Opensource GIS

Is there some solution for calculating minimum and maximum width for overlay of two polygon strips? When I clip these strips the result is another strip with variable width about 1 km and 20 km long. ...
4
votes
1answer
2k views

Convert shapefile lines to a polygon in GRASS

I have a shapefile of a map that is the outline of a number of islands. I would like to convert the lines into polygons (ie all islands filled in) using GRASS. I searched on how to do this with GRASS ...
2
votes
0answers
16 views

Error ET Geowizard Clean Polygon() takes no arguments (3 given)

I want to clean polygon feature classes with ET Geowizards (clean polygon) because I cannot find any tool within ArcMap (ArcInfo) that does the same. I have really small gaps within the polygons (but ...
2
votes
2answers
61 views

How to extract a new linestring vector from a existing multipolygon in QGIS?

What I want to do: create a new line (named linestring in Postgis?) from existing multipolygon layer in Postgis. Purpose: once these lines are created, I'll run some distance calcs from specific ...
6
votes
1answer
2k views

How can I transform a polygon to a linestring in QGIS?

I have a polygon, imported from a shapefile in QGIS. I would like transform it to a linestring instead so I can save it as a GPX file later. How can I transform a polygon to a linestring in QGIS?
1
vote
1answer
3k views

Openlayers get coordinates of a circle vector after draw

I have made a openlayers map. I have made two features on the map. Navigate DRAW POLYGON I have made 40 sides to my polygon which turns out to be a circle. After I have drawn my circle I want to ...
1
vote
2answers
44 views

Where to find neighborhood boundaries for Israel?

Is there a place that has neighborhood boundary data for Israeli cities as polygons? I have searched the web without results.
1
vote
1answer
52 views

r - increase speed of crop, mask, & extract raster by many polygons

I'm extracting the area and percent cover of different land use types from a raster based on several thousand polygon boundaries. I've found that the extract function works much faster if I iterate ...
3
votes
1answer
113 views

How to map flood areas from a set of points containing surface and height of water?

I am working on the damages made by the typhoon Haiyan. I use QGIS 2.0 with extensions and toolbox, and MapInfo. I have vectors, rasters of the place. I want to map the flood area along the ...
4
votes
2answers
3k views

How to find polygons within polygon using ArcGIS Desktop?

I am new to GIS and ArcGIS. I have a problem I need to solve: I have a set of polygons, some of which enclose other polygons. They are lake polygons, and within lake polygons, are smaller island ...
1
vote
1answer
30 views

postgis calculate distance between point & polygon/circle

By basic requirement is to find the nearby fences to a particular point(user lat long alt) within a N meters. I have list of polygon/circle in DB with 900913 srid ...
2
votes
1answer
222 views

Why is field calculator returning NULL for $x and $y in line and polygon layers?

I am trying to include XY coordinates in the attribute tables of several of my vector files; they are line and polygon files. I have tried two methods; first I used $x and $y in the field calculator ...
2
votes
1answer
201 views

Determine when I have crossed state line?

We are currently using the Google Maps API to get route information and total mileage but we would like to determine when we are crossing into a new state. When we return the route information we can ...
8
votes
2answers
4k views

Converting point sets to polygon boundaries

I'm trying to convert sets of points to their respective polygon boundaries. I think this is something like a Voronoi diagram or Convex Hull, but not quite. I'm sure there's a technical term for it, ...
8
votes
5answers
6k views

How do I convert a Polygon into a single or all Points?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)
0
votes
1answer
145 views

The best way to convert points to polygons using ArcObjects

I have a set of points from GPS I want to convert them to polygons..I have two approaches to do this.1- convert points to polygon..I do this with below code: private IPolygon ...
1
vote
1answer
57 views

Convert polygon to point with QGIS [duplicate]

I work with QGIS and I tried to convert polygon into point. I need points all over the perimeter of the polygon. I saw several answers like: Problems converting polygon to point but I didn't see an ...
0
votes
2answers
834 views

How to get a list of OSM relations (id numbers) of cities and countries only?

I want to get OSM polygon shapes (GEOJson or WKT) of countries and cities only. I know that it is called a "relation" in OSM and each relation has its own id (New York is 175905, for example). How may ...
3
votes
1answer
115 views

Postgis 2.0 geographic polygon has max longitudinal range

My problem is that I have a load of geographic point data (srid 4326) in a table. A user may do a bounding box search - essentially create a polygon as follows: l_poly geography(Polygon,4326):= ...
1
vote
1answer
19 views

Calculate raster mode with r.mode - problem with decimals

I am working with a raster file that represents the percentage of vinyards by commune (e.g., municipality) in a region in France. The statistics were calculated for each commune based on surveys from ...
0
votes
0answers
3 views

Clip Multipatch Feature class with Polygon Feature Clas

i have city_gml data with 3D buildings lod2. I now want to extract the buildings which intersect with a polygon feature class and create a new multipatch feature class. How can I do that? Thanks in ...