Questions tagged [polygon]

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
26 views

Converting single line into polygon plane in QGIS?

Is there a way to convert a line or multiple lines into polygon? I have a feature attribute as with, and the line represents the road. I want to convert every route into a polygon plane that somewhat ...
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3answers
60 views

Find the NW vertex of a rotated polygon

I am using QGIS 2.18 and I am wondering how to find the NW corner of a polygon and create an attribute of that point number. See the attached image. For example, please node 8 is the NW corner for ...
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2answers
721 views

Avoiding/getting rid of topological errors after dissolve?

After dissolving a layer in QGIS 2.8, I get a lot of topological errors in the new (dissolved) layer. Any suggestions as to how to get rid of these errors without manually editing each one? update: ...
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2answers
2k views

Deleting small gaps (slivers) between polygons?

I try to delete the slivers that appeared when I have merged some polygons. I have two different cases: For the CASE 1, no problem I fill the gap with: CREATE OR REPLACE FUNCTION sliver_killer(...
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3answers
42 views

Concatenating list of strings using ArcPy?

My code from Returning strings showing all vertices from all polygons in shapefile using ArcPy? creates is the following: import arcpy fc=r'D:\GIS Data\TOOLS\EV calc in Python\Data.gdb\PolyWGS842' ...
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1answer
28 views

QGIS: Smoothing two polygon sets where polygons are nearly adjacent

I have two polygon sets, one representing cities, the other representing school districts. I am trying to create a relationship between cities and districts, but I have a problem where the cities and ...
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4answers
5k views

Removing lines from inside polygon in QGIS

Through a "dissolve" process in QGIS, I achieved some defective polygons generated after dissolve process that have some fails, like these in the screenshot: Is there any automatic process I can make ...
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1answer
24 views

Unremovable objects/lines QGIS 3.x

How can I remove "red lines" that become permanent to my map canvas while trying to digitize different shapes. The program just leaves the outline of what I'm trying to draw. It still remains even if ...
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2answers
2k views

Finding points along a path

I am unsure of the best approach to this problem. I can think of some ways of doing it which I will list below but I am looking for the best and most efficient way of doing this. Problem Given a ...
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0answers
17 views

max elev value from raster [on hold]

data: raster (srtm) polygons a. (1 degree grid) polygons b. buffer from polygon a. (1 degree grid with outer buffer 8 km.they overlapped) HOW to take: max elevation in every polygon a. max ...
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1answer
12 views

Removing empty polygon from sf object in R?

I have such object: > p_mb Simple feature collection with 52 features and 0 fields (with 9 geometries empty) geometry type: GEOMETRY dimension: XY bbox: xmin: 585001.4 ymin: 211001....
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2answers
36 views

Adding information to polygons inside polygon from other polygon in QGIS?

I have two layers in QGIS. The first one contains buildings and the second one contains blocks. Now I want to add the ID of the block to all buildings inside this block. Are there any functions in ...
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1answer
31 views

Remove polygons having less than 4 coordinates in R

I have a multiPolygon shapefile of buildings in a particular city. I read it in with readOGR and and transform it to my desired planar projection with the following code: buildings_data<-readOGR("...
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2answers
15 views

Deleting polygon defined area from multi band raster layer in ArcGIS Desktop?

This is a similar question to Deleting polygon defined area from raster layer in ArcGIS Desktop?, but I need the answer to be able to apply to multi bands since I am working with a RGB file. I have a ...
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1answer
17 views

Split polygons by area/percentage with QGIS 3.x

Is there a function in QGIS 3.6 Noosa that allows me to split polygons with given area or percentage? There is a plugin for QGIS 2. "split polygons" that seems to have exactly what I'm looking for, ...
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0answers
28 views

LSIB feature does not align with island boundary in Google Earth Engine?

It looks like there is an alignment issue that arises in EarthEngine with the LSIB polygons. It exists for Greenland in both the Detailed LSIB 2013 and Simple LSIB 2017 datasets, and can be verified ...
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0answers
29 views

How to correct border between 2 polygons in R? [duplicate]

What algorithm to use to correct (average) the borderline between 2 polygons? All I know is that they have their own borderlines very close to each other. Sometimes they may overlap, otherwise not. ...
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1answer
64 views

Returning strings showing all vertices from all polygons in shapefile using ArcPy?

I want to have a string showing all vertices from all polygons in a shapefile. In my example below my code lists all vertices and the first column shows the polygon they are part of (I only have 2 in ...
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0answers
15 views

Splitting a layer containing multiple polygons into multiple layers each containing one polygon [duplicate]

So firstly, I used the buffer tool in Qgis3 to create (twenty) polygons with a certain width from (twenty) points. This lead to the situation below, where o1 and o2 are two original points and 1 and 2 ...
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0answers
31 views

QGIS: Polygonize error

Running the Polygonize tool in QGIS keeps generating the following error: Processing algorithm… Algorithm 'Polygonize (raster to vector)' starting… Input parameters: { 'BAND' : 1, '...
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0answers
15 views

Polygon boundary is not properly connected in R

I have two points sets, when plotted using geom_point, they look like: What I want to do is draw a polygon using these two datasets, and I expect to get a ring-shape polygon. However, when I use ...
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1answer
23 views

Rotating Polygon in 3D Space as KML for Google Earth?

I'm trying to create this effect in a KML to be displayed in Google Earth. I am writing in KML 2.1 as a reference. I know it is possible to create a polygon that is circular in appearance, but can ...
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1answer
28 views

Polygonize specific raster values QGIS

I have a raster of 36 classes of the land cover in South Africa. However, I only need 4 of these classes and create a polygon out of these 4 classes combined. I have now used the raster calculator to ...
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0answers
37 views

Adding Polygon to shapefile of particular area from Excel?

I have Excel data in which polygon number is given, in correspondence to that there is particular Area given. I have 5000 to these entries. Now in the shape file, we have to edit every polygon and add ...
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1answer
222 views

Listing All Points In a Polygon Feature Class Using arcPy [closed]

Based on my understanding in coding, I thought the following code will list all points in every feature in my Building polygon feature class: arcpy.env.workspace=r'D:\test.gdb' rows=arcpy.da....
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4answers
4k views

Querying points inside and outside of polygons?

In PostGIS I have two tables: Table that contains polygons: table a.provinces gid | geom | name | ------------------------------ 1 | 010604 ... | Champagne | Table that contains ...
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0answers
23 views

How to get middle line of buffered shape in R? [closed]

Just simply, what function to use to get the middle line of such shape? This is a product of sf::st_buffer( ) function and these are 2 polygons, smaller and larger. How to get average one (in the ...
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1answer
56 views

Making path between polygon using QGIS?

I am trying to draw a line (vector layer) of a certain length that that tries as much as possible to dodge the green polygons. Assuming a starting point, is there some sort of line centroid ...
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1answer
1k views

Removing (defined) sliver polygons using PostGIS? [closed]

How do I write SQL (for PostGIS in PostgreSQL) to remove sliver polygons (including long narrow slivers and some small irregular polygons that were erroneous 'gaps' in the original dataset) from my ...
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0answers
18 views

Will Polygon Volume work if my polygon does not represent a constant plane height?

I am working on calculating flood inundation volume in ArcMap. I have polygon layers that represent flood inundation at specific recurrence intervals. My layers do not have a constant plane height ...
2
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1answer
38 views

Unclosed linestring to polygon works with QGIS but not with PostGIS

Just like the title, I am extracting OSM riverbank and a lot of riverbanks in OSM is in 'unclosed' linestring. This is the original river shape i extracted from OSM In order to polygonize the ...
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1answer
29 views

Draw Polygon using other lines in different shapefiles?

I have a scenario where i need to update a database. I have several shapefiles from which I get the data from. I need to draw polygons inside certain borders, and the borders don't always come from ...
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1answer
19 views

Draw a polygon following a centreline in Google Earth

I am trying to draw a buffer of 30km distance around a path I have in google earth. I need this buffer as a polygon as I need to export it to XML for a different purpose. Is there any way to do this ...
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3answers
28 views

Merging different types (e.g., polygon with polyline) of shapefiles? [duplicate]

I want to create a watershed shapefile with areas, streams and pour points in it. Is there a way to merge the areas (polygons) with streams (polylines) and pourpoints (points)?
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1answer
389 views

How to get or assign vertex id to polygon vertices and use these as vertex label using pyqgis?

I want to create parcels (polygons/polyline) maps with the vertices labeled incrementally by vertex id using pyqgis/QGIS. I normally do this by converting the polygon/polyline to point layer and ...
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0answers
23 views

Easy way to plot separate groups of SpatialPolygons in R

I have SpatialPolygons grouped by 81 polygons and in each there are some other Polygons I'd like to plot them group by group but have little trouble with it. > rtu_spl class : ...
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0answers
27 views

ArcMap: interpolation for single polygons individually

The red polygons in the image represent the boundary of infills. The raster (colored area) within the polygons is interpolated from the point shape file (black dots). The image shows an example where ...
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0answers
36 views

Creating buffer for polygon in R

I am quite new to GIS area. I have a polygon and use concave hull function I could get a boundary like this What I what to do is add a certain-width band along the boundary, so that it could look ...
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3answers
379 views

Zooming into a particular polygon

I am getting the polygon id by doing identifyParams.geometry = evt.mapPoint; identifyParams.mapExtent = map.extent; identifyTask.execute(identifyParams, function(result) { var i; var ...
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0answers
27 views

Assign different colours to intersection between two polygons and difference area

I am quite new to GIS using R. I have two sets of data, upon which I could create two polygons like this: What I want to do is colour the common area (inner 'circle') and the space between borders. ...
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1answer
130 views

Finding overlapping polygons in two shapefiles and deleting them in R? [closed]

I have two shapefiles with more than 1000 polygons each, and they represent two types of agricultural fields in the same area, which means they should be different types. Some of the polygons are ...
3
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1answer
596 views

Using Check Geometries plugin for polygons in QGIS?

I've a few hundred polygon features with many duplicate nodes, gaps, overlaps and other geometry errors. Fixing all errors seems to be quite tricky. I had to run the duplicate nodes check twice to fix ...
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0answers
15 views

Creating additional attributes for regional intersections?

A certain country is (simultaneously and independently) divided into 400 regions and 100 judicial districts. Each division is represented by a separate multipolygon layers with units as features. ...
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1answer
119 views

Using attributes of polygon in one layer to identify polygons in another? [closed]

I am in the process of developing a web application, I am using open source tools so qgis, postgis, play framework for the web app. And I have come across an interesting problem that I'm trying to ...
0
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1answer
709 views

Converting polyline to fixed width polygon using QGIS?

I have a shapefile of polylines for trails, and I need to convert them all to be polygons that are 8 ft wide (4 ft from the center of each side of the polyline). I tried a following a few other posts ...
2
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1answer
79 views

Sampling random cells from certain areas of a cropped raster?

I have a raster cropped to the extent of some glaciers and divided it into three masks to address inner glacial cells, border cells and non-glacier cells adjacent to the glacier. Data can be found ...
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0answers
31 views

QGIS Time Manager with joined layers

I am using QGIS version 3.6 and Time Manager version 3.2.3 to create a temporal map of the US's energy usage over time. I have a polygonal shapefile of the US with each row of the .dbf file containing ...
2
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2answers
5k views

Merging attribute and geometric features in QGIS?

I have polygons shapefile in which some of the polygons have same attributes as seen below:- In QGIS, how do I merge the polygons having the same attributes into one polygon? In other words, am ...
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3answers
2k views

“Identity” overlay in QGIS?

I have two polygon layers I'd like to overlay using QGIS or another open source tool. What I want as output is a polygon layer with the extent of one polygon, but with each polygon in that layer ...
29
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9answers
27k views

Generate points that lie inside polygon

I have polygon feature and want to be able to generate points inside it. I need this for one classification task. Generating random points until one is inside the polygon wouldn't work because it's ...