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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2
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1answer
1k views

Convert GeoJSON with multiple Polygons and MultiPolygons into single MultiPolygon?

Is this even possible? I have a GeoJSON file with multiple polygons and multipolygons, and I need to set styling on them (in Leaflet.js). I'd like to create a single, large MultiPolygon from the ...
3
votes
2answers
400 views

Can't transform lines to polygons

I have a similar question to: How to join lines in QGIS for later using "lines to poly"? I have a line shapefile that I wish to transform into a polygon shapefile. After making some ...
13
votes
2answers
506 views

Group polygon features to match a set of specifications

I have two different sets of polygon features (398 census tracts and 80 ZIP codes) that each roll up to a larger feature (a US county). Though census tracts are smaller than ZIP codes, they do not ...
5
votes
2answers
2k views

Export selected raster cells to polygon

I have selected certain values in a raster (roughly 1000 cells), and would like to export them to be able to create a polygon. Converting it to points first then to polygons does not work. Can anyone ...
2
votes
2answers
48 views

Semantics of polygon points - How to join the dots?

The question arise from reading the standard "OGC® Sensor Planning Service Interface Standard 2.0 Earth Observation Satellite Tasking Extension", that you can get from ...
2
votes
0answers
67 views

Area Calculations dont agree after raster to polygon conversion

I have a landsat 8 image [UTM 19s] (30m resolution, so 900m sq per pixel). I need to calculate the total area (hectares) from a land cover type. I take the count of pixels from the attribute table, ...
7
votes
1answer
7k views

How to convert a String to OpenLayers.Geometry.Polygon using javascript?

First let me say that I'm using Javascript, jQuery, Java, GeoServer, OpenLayers and PostGIS. Using java class ResultSet I return this String: POLYGON((516000 2135000,515039.264020162 ...
0
votes
0answers
63 views

Creating holes in polygon using Leaflet draw?

I want to load some geojson data into Leaflet draw and allow the user to edit the polygons and also add holes inside polygons.
6
votes
4answers
16k views

How to Merge/Dissolve Polygons By Common Attribute Field in QGIS?

I have joined corresponding Local Enterprise Partnerships table data into a polygon shape file containing UK Local Authorities. How do I Dissolve or Merge the the Local Authorities polygons by ...
2
votes
4answers
153 views

Python Library for converting GeoJSON Multi-polygon to polygon

I would like to know if there is a Python library that can be used to convert GeoJSON Multi-polygon to a Polygon. Note: i want to convert .geojson file Multi-Polygon feature type to Polygon feature ...
1
vote
2answers
560 views

Label inside top left corner of polygons using MapInfo Professional?

Does anyone know of a tool or procedure to automatically place a label in the corner of a polygon, rather than at the centroid? I am using Mapinfo and know that I can manually place the label ...
8
votes
4answers
173 views

How to create a polygon connecting the endpoints of multiple lines using python?

I'm trying to figure out how to create a polygon that connects all the endpoints of a shapefile containing a set of polyilnes with pythonscript in ArcGIS, I'm having trouble doing this as the order of ...
2
votes
1answer
1k views

How to fetch polygons from PostGIS into a PHP array?

Currently I fetch polygons from a database table using ST_AsText(). The results are in text format, like this: POLYGON((84 104,212 48,321 122,243 179,275 238,131 240,84 104)) I am not quite sure if ...
0
votes
2answers
2k views

Calculating shape perimeter/area per zone in ArcGis 10

How can I calculate geometrical features of polygon (perimeter and area) per zone (similar to zonal stats for rasters)? I have a square fishnet (approx 20x35, 1 square kilometer each) and I need to ...
4
votes
4answers
3k views

Clip raster using shapefile into multiple rasters using ArcGIS Desktop?

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 ...
3
votes
2answers
301 views

Area in KM from Polygon of coordinates

I have polygons from coordinates in (python shapely) that looks like this POLYGON ((24.8085317 46.8512821, 24.7986952 46.8574619, 24.8088238 46.8664741, 24.8155239 46.8576335, 24.8085317 46.8512821)) ...
0
votes
0answers
34 views

Geological map generalization polygon aggregation

I am working on generalization of Geological maps and the first thing I am wondering about is aggregation of separate patches that may have same class and which are closely situated to each other. ...
1
vote
1answer
68 views

Calculating the length of the network lines inside polygon in QGIS 2.10.1

I am working with 2 datasets: delineations of the neighbourhoods traffic network. This is how they look: I would like to calculate the length of the roads per neighbourhood (polygon). As you ...
3
votes
0answers
30 views

How do you show agreement between polygons based on hand-drawn maps?

I'm somewhat new to GIS, coming from a linguistic background, and now I'm trying to make QGIS do something that I want from that background. I have some hand drawn maps with certain areas of the ...
5
votes
2answers
135 views

Move a layer in QGIS to a precise position based on centroid

I'm not quite sure how to phrase this so apologies if it is a duplicate. I have a project that uses a series of lines created from the boundaries of polygons overlaid onto a map in QGIS. I understand ...
2
votes
2answers
335 views

Clipping raster to multiple rasters for each parcel using ArcGIS Desktop?

I have a raster aerial photo. I have county wide parcel data. I want to clip/screen shot the raster at each individual parcel. Think of this application - a post card with an image of your house ...
14
votes
4answers
25k views

How to convert .shp to .csv including attributes AND geometry?

I have a .shp file with 60k+ entries, all of which are polygons with corresponding attributes (acreage totals, landowner names, tax ID #s, etc.). What I ultimately need is a .csv file with all of ...
5
votes
1answer
129 views

Create shapefile of raster outline using python

I want to create a single bounding shapefile polygon of valid pixels in raster data (GeoTIFF) using python. I need something efficient as I need to do this for hundreds of rasters. I had thought of ...
3
votes
1answer
66 views

Clipping points by a polygon attribute in QGIS

I am trying to clip a point layer with a polygon layer. My polygon layer has multiple polygons (e.g. country with different states). I am wanting to clip the point layer based on the different states ...
2
votes
2answers
59 views

Selection on Overlapping Polygons

I have converted a CAD file to GIS format using GIS (from .dgn to .shp)... In one layer I have polygons in which a smaller one is on top of the larger polygon. I can see both polygons however when I ...
0
votes
1answer
50 views

Multply polygon with raster

I have a countries' polygon with an attribute table. I also have a raster. I want to multiply the values of the polygon (of each country) with the raster. Polygon Countries Cost C1 X ...
6
votes
1answer
75 views

How to make a wedge shapefile in R?

I'm quite okay at R programming, but fairly new in GIS (especially in R). I have a set of coordinates and I'd like to create a custom shape around them. What I want to do step-by-step: Create a ...
1
vote
1answer
256 views

Adding custom polygons in google maps

Do you have any experience with adding custom polygons in to the google maps? I have made polygons from raster layer. And my goal is to show this layer in google maps. For now i have experience with ...
1
vote
2answers
100 views

What algorithm allows me to calculate the set of all points inside a polygon?

Imagine I have a polygon, which represents the countours of a building on an integer 3D map (everything is a 1 meter by 1 meter block in that map). In the image below, you see several buildings ...
7
votes
1answer
676 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 ...
2
votes
3answers
109 views

Remove islands and completely surrounded polygons after polygonization with QGIS

I have a line map of buildings in a city. I was able to correctly polygonize the buildings in QGIS with the Polygonize processing algorithm. All the holes/islands became features as expected. Now I ...
1
vote
2answers
125 views

How to fill holes in polygons automatically?

Is there an option in QGIS to fill holes in polygons automatically by setting parameters e.g. maximum area, distance between borderlines? I want to delete/fill holes that a very "thin"/small.
3
votes
2answers
4k views

Measure the area of a polygon resulting from the intersection of two other polygons?

How can I measure the area of a polygon resulting from the intersection of two other polygons? If I use the measure tool or open the attribute table for the resulting polygon, it shows me the areas of ...
0
votes
0answers
21 views

Combining Spatially Neighboring Polygons up to numeric count limit (from field) then starting over using ArcGIS for Desktop?

I am using ArcGIS 10.2.2 for Desktop (Advanced License). I've tried to find an answer to this, but it's very difficult to describe. I'm hoping there is a built in function that will allow me to do ...
1
vote
0answers
24 views

Rotate functions in “Rectangles, Ovals Digitizing” as well as “Advanced Digitizing” distort shape dimensions

I am trying to rotate squares via the rotate tool in the "Rectangles Ovals Digitizing" Plugin in QGIS. The dimensions/proportions of the sides, however, are distorted whenever I do so. Any idea of why ...
1
vote
1answer
146 views

Create polygons from points representing the corner vertices (ArcGIS)?

I am on ArcGIS 10.3.1. I have a point feature class that represents the corner vertices of the polygons. They are located in a regular grid. The labels represent the OBJECTID. The points can be ...
1
vote
0answers
22 views

Create a center node based on both polygon and line shapefile

Sorry for cross posting. I want to develop a node layer from two other layers. One of the layers is a polygon contains a series of zones. Another layer is a line layer of roads. The nodes I want to ...
1
vote
1answer
78 views

What does v.distance calculate excactly?

As I am from an economics department, I am quite a beginner in QGIS. I read, that if I wanted to calculate the distance from a polygon to a point/line/other polygon, I should use the GRASS plugin ...
1
vote
1answer
99 views

Labeling outside polygon using QGIS?

is it possible to place a label automatically outside its polygon?
8
votes
1answer
464 views

How exactly is the centroid of polygons calculated?

I would like to know how exactly QGIS Geometry tools -> polygon centroid is calculating the point coordinates. For example does it divide the boarder of the polygon into small points, take two pairs ...
0
votes
0answers
44 views

Union overlapping shapefiles (poylgons) and merge the attributes where overlap occurs in R

I have 30 shapefiles of overlapping polygons and would like to union them into one shapefile. The attribute table of the 30 layers is exactly the same (two columns, Type and Origin). A new polygon ...
0
votes
1answer
56 views

Inserting field-based hyperlinks in non-spatial tables

I am trying to insert field-based hyperlinks into a non-spatial table in arc 10.3. The idea is simple, open the table and click on the link. I am able to add hyperlinks to spatial fields, and click ...
1
vote
1answer
44 views

How do I perform a Union (as per ArcGIS and QGIS) in MapInfo

I am running MapInfo 15.0 and need to perform a Union of two polygon layers (i.e. combine the two and preserve all boundaries and associated attributes). I know there is some ambiguity over the term ...
0
votes
0answers
24 views

Add a point inside a polygon randomly

If I have a polygon and a set of points all contained within the polygon. How would I best add a new point to the point set such that:- a) it was contained within the polygon b) it was spaced at ...
2
votes
2answers
785 views

Selecting polygon features that have centers outside of another polygon feature class using ArcMap/ArcPy?

Since I only have Incorporated area feature class, how can I select census blocks that are in unincorporated area? Or not within any incorporated areas using ArcMap or ArcPy?
6
votes
1answer
1k views

Creating Multi-Part Polygons that touch internally using ArcGIS for Desktop?

I have a set of parcels as illustrated in the image below. There are currently no multi-part features in dataset. What I would like to do is to merge (not the right word) all of the parcels with same ...
1
vote
1answer
352 views

R solution for 'TopologyException: Input geom 1 is invalid' self-intersection error?

The 'TopologyException: Input geom 1 is invalid' self-intersection error which arises from invalid polygon geometries has been widely discussed. However, I haven't found a convenient solution on the ...
2
votes
0answers
68 views

Is there a way to draw polygons with a fixed area?

I am looking for a way to draw polygons with a fixed area. I am currently mapping farming options on field parcels. Some areas such as buffer strips run along features like rivers and hedgerows so ...
1
vote
1answer
63 views

What does double digitized polygon mean?

I know what is a polygon but when a polygon is said to be double digitized? I failed to find a suitable meaning of double digitized after googling. I understand double digitized means digitized ...
3
votes
1answer
3k views

merging 2 polygon adjacent to each other using R

I have several shp files which are the components (or tiles) of a map, I have joint all these tiles together to have a large shp file. Then I realized some of the polygon is now split into 2 halves, ...