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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0
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1answer
25 views

How to calculate the area of polygon features within another polygon feature layer

As shown below, I would like to calculate the percentage of each red feature (landscape zones) taken up by a green feature (forest zone). So I need the summed percentage of forest zone for each ...
3
votes
1answer
194 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 geometry(...
7
votes
3answers
815 views

Lossless Polygon Simplification?

Is there a standard/recommended algorithm for simplifying a polygon without shrinking any of its original boundaries? Right now I'm using TopologyPreservingSimplifer within JTS and running into ...
2
votes
1answer
34 views

Getting polygons out of multi-polygon GeoJSON files?

I am a farmer and very new to GIS. I am trying to load shapefiles or KML files to an online site/service called FarmLogs.com. Once my "fields" are uploaded the site can tell me the amount of ...
-1
votes
1answer
24 views

Finding common two vertices for two adjacent polygons and drawing line feature connecting them in ArcGIS for Desktop?

I need to find the common two vertices between two adjacent polygon and draw a line feature connecting these two common vertices: I have tried the following code but it is not working: polygon1 = ...
2
votes
3answers
884 views

Iterating polygons on a SpatialPolygonsDataFrame in R with readWKT

I have fetched some data (39 objects) from my PostGIS database and converted this data into a matrix: rs <- dbSendQuery(con, "SELECT ST_AsText(polygon_accumulation) AS ShapeWKT from accumulation;")...
1
vote
1answer
38 views

Plot multiple buffers around points

I have three buffer radius sizes radius<-c(1000,700,500) that I have placed around an array of points (two example points are given here in the file SourcePlace). What I'd like to do is ...
0
votes
1answer
26 views

Extend polygons to match another polygon in ArcGIS

I am struggling with this task :( I have various layers, all having a common outer shape (see the blue polygon in the picture). On of those polygons however, has a different shape. I somehow need ...
3
votes
2answers
62 views

PostGIS - Get a point inside a line or polygon

I need to get the center point of a line or polygon to make marker for my app. So that when you click a marker the geometry appears (line or polygon). I used ST_Centroid to make it work. The result ...
0
votes
1answer
27 views

Auto-Create polygons from Geo-referenced PDF

Is it possible to automatically create polygons/features from a georeferenced PDF? I'd like to geo-reference an expanded view of the below linked pdf, and then have each of the tracts created ...
1
vote
1answer
527 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 ...
1
vote
1answer
55 views

In QGIS is there a way to make one polygon out of several

I'm trying to use QGIS to get a more simplified vector country data. For example Canada has several bits to the north all as separate polygons where as I'd be happy to just take a rough outline of the ...
15
votes
6answers
17k views

Performing reverse clip in ArcMap?

Is there a way to perform a 'reverse' of the clip function in ArcMap? I am not exactly sure how to explain this so here is a diagram:
0
votes
0answers
31 views

Intersecting polygons to a focal polygon with the same cell ID and also obtaining the length of the joining edge [closed]

I have a series of polygons, where there is a focal polygon (a type of coral reef). The other polygons are cut to the centroid of a cell where the focal polygon is included. The cell ID is given by ...
2
votes
1answer
43 views

Make square polygon from one point and area

I have a shapefile of points with a variety of attributes, the relevant ones being "ID", "area", "lat", and "long". Such as... The lat/long coordinates are always the SW corner of a plot and the area ...
1
vote
1answer
22 views

Wrong boundary when plotting Canada's shapefile in Python

I want to plot the Canadian shapefile with province boundaries highlighted and hollow filling. I have downloaded the shapefile from here. This is the script I use to visualize the shapefile: ...
1
vote
0answers
38 views

Iterate through multiple polygons to produce a table with elevations using a DEM

My question is similar to this: Iterate through multiple Raster files and compute statistics using Zonal Statistics However, what I want to do is use Model builder to use individual polygons to ...
2
votes
2answers
29 views

Postgis meassuring distance between first and third points of a polygon

I am using ST_DumpPoints() function first to get the list of the different points in the polygon but after doing that, the first point is in one record and the third point is in another record and I ...
0
votes
1answer
19 views

Carto DB city border polygons issue?

I want to visualize some statistical data about my country and I'm using the CartoDB geocoder. I've city names and I want to see cities as polygons but CartoDB says it has no polygon data, it can only ...
7
votes
5answers
6k 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 ...
6
votes
2answers
9k views

Createing polygon layer from point data using QGIS?

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 ...
1
vote
3answers
72 views

Erasing small polygons from bigger overlapped polygons using ArcGIS for Desktop?

I have different bigger polygons (buffers) which are overlapped (A,B,C,...) and the inner smaller ones (a,b,c,...). I want to erase smaller ones from bigger ones in the way the results be A-a, B-b, C-...
2
votes
2answers
182 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 ...
1
vote
1answer
20 views

Weighted polygon-feature-classes combination/overlay analysis using ArcGIS for Desktop?

I have several (sometimes, not always overlapping) Polygon Feature Classes which are all weighted/ranked through a field from 1 to 10 (10 is best). I would like to combine/overlay these layers them, ...
2
votes
3answers
6k views

How to aggregate points to polygons using ArcGIS Desktop?

I am trying to aggregate my data points to the polygons so that I could find out how many points I actually have in each polygon, and then export the data contained within each polygon to further look ...
0
votes
1answer
418 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 ...
1
vote
0answers
34 views

How to remove circles from new polygons in QGIS? [closed]

I've just started using QGIS (2.6.0-Brighton). Every time I create a new polygon, a circle appears in the center (see below). I thought this might just be a feature of QGIS editing that helps you to ...
6
votes
2answers
3k views

Count number of unique raster pixels in polygon using ArcMap?

I have a polygon shapefile and I want to generate a table of a count for each pixel value in each polygon. My main goal is to find out what pixel is most abundant in each polygon. I am using ArcMap ...
1
vote
0answers
36 views

How to smooth “internal” polygon borders

This is my first foray into GIS and GIS software. I am using ArcMap currently. I have a shapefile of the world divided into different ecological regions. I would like to reduce the file size by ...
1
vote
1answer
24 views

Using ModelBuilder to create smaller individual DEMs from a large DEM using multiple polygon?

How can I use a polygon (which is made up of smaller polygons) to create individual DEMs from a large DEM using the polygons as the mask/extent? I am trying to do this in ModelBuilder and it isn't ...
6
votes
1answer
433 views

Permanently setting polygon/polyline segment length using ArcGIS Desktop?

I'm trying to create a several hundred polygons in ArcGIS 10, each of which may have up to several hundred vertices. For consistency sake I would like each line segment in these polygons to be of a ...
2
votes
2answers
221 views

Split polygon based on line segment

I am trying to split a street polygon based on the segment ID of the street, giving them the same segment_ID in the attribute table of the street lines. I did not use the line feature class to derive ...
2
votes
1answer
191 views

Is there a way to clip a polygon layer according to DEM elevation?

I have a polygon layer on top of a DEM. Is there a way to clip the polygon layer according to elevation, ie the clipped result being only those areas of the polygon layer between x and y altitude? ...
2
votes
1answer
205 views

Intersection between polylines feature to polygon in QGIS

I would like to transform a line shapefile into polygons. However, the tool Vector>Geometry>Line to Polygon doesn'to work to me. What I would like to do is using the intersection between lines and ...
1
vote
1answer
22 views

Can I statistically smooth attributes spatially (using distance/surrounding polygons) in ArcGIS?

I have Census Areas with some of the Census attributes. Is it possible to take an attribute, for example, percentage of people in full time employment, and derive a spatially smoothed version of the ...
3
votes
1answer
483 views

How do I smooth edges of polygons in QGIS?

Is there a built in function or plugin I can use to achieve smooth lines for my polygons instead of the blocky ones I have now?
0
votes
0answers
14 views

ArcMap Feature to Polygon loses z-values on some polygons

I created line features from points containing Z values with the Points to Line tool and then, after some manual clean-up involving connecting some lines properly and merging them, I tried to make ...
0
votes
0answers
9 views

Insert a row with the_geom polygon!

I'm a beginner, i'm looking for a sql insert store with item having the the_geom style of polygon. I know the way to insert row with point like that: CDB_LatLng(10.51, 20.51), so can i do the same ...
0
votes
2answers
346 views

Extracting multiple values of raster to polygons using ArcGIS for Desktop?

I was hoping I could get some help on how to extract information from a land use raster using polygons. I have a layer with 157 polygons and a land use raster with multiple land use categories for the ...
11
votes
4answers
47k views

Creating polygons from lines using ArcEditor/Standard level license of ArcGIS Desktop?

I am trying to create polygons from a line layer of lots and concessions (large blocks of land in rural areas). The lines are mainly grid style as they intersect mostly at right angles. I need to ...
12
votes
0answers
525 views

Writing Python script for ArcGIS to square polygon corners? [closed]

I'm looking for a script that will square the corners of polygons that are near 90 degrees but not exactly. Near could be dealt with via a variable, for example within 5 degrees of 90 (85 - 95 degrees)...
1
vote
2answers
581 views

How to resample polygon vertices so that they are evenly spaced in Arc 10

I have digitized the outline of many river channels (by both manually picking points and using streaming mode), but now I need the vertices to be evenly spaced (for input to another program). I tried ...
1
vote
1answer
115 views

Finding all polygons inside of a polygon

How to find all the polygons inside of a polygon? I tried ST_Intersects and ST_Contains but they are booleans variables. I have a list of polygons in WKT format, so I am trying to pull all the ...
0
votes
1answer
24 views

Not all polygons digitize when converted from lines

I have a polyline feature consisting of a grid. I attempted to convert this grid into a polygon using the "Feature to Polygon" geoprocessing tool, and it appears that not all lines have been carried ...
0
votes
1answer
44 views

How to find the distance between neighboring points in ArcGIS 10.3?

I have two shape files: one has point features indicating urban centers, the other is a polygon features file that has counties. Each county has one urban center. There are around 2800 counties. I ...
1
vote
0answers
45 views

Shapefile layer export issue

I am using QGIS to define polygons in a shapefile layer which I am then exporting as an ESRI shapefile for use with JMP. The polygon layer looks correct on-screen in QGIS, but the exported files have ...
0
votes
0answers
14 views

Arcmap 10.2 (query builder and or Expression)

I want to turn off selected sect_label numbers from showing up on my base map as I have a shapefile with Section and acreage loaded for a specific area and i need to use the shape file because it lets ...
0
votes
1answer
1k views

How to narrow the result from Nominatim with only cities and countries, no additional areas with the same name?

I'm trying to get WKT or GeoJson polygons of cities and countries from Nominatim (for example, Paris and France). I send a GET request but it returns me several results named "Paris" or "France". How ...