Questions tagged [ellipse]

In mathematics, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis. An ellipse is also the locus of all points of the plane whose distances to two fixed points add to the same constant.

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Creating ellipse symbols with defining size of the minor and major axes in QGIS

In QGIS 3.20 (or QGIS 3.18) I have a shapefile with point geometry, this shapefile has a field with the value of error in "x" and a field with the value of error in "y". I would ...
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QGIS 3.18.3: Reshape Feature - Cut from Polygon with Ellipse

I have basic polygon/rectangle which, I would like to cut part of it using Reshape Feature. All works good when, I do the reshape by drawing another polygon, which cuts parts of my basic polygon/...
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2 answers
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Intersect two polygons but preserving the shape of one

I have two polygons layers; a selection of land titles and a buffer layer. I want to intersect the two layers but preserve the shape of the land title polygon to show all the land plots that touch the ...
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7 votes
2 answers
247 views

Buffering an ellipse on a points layer in QGIS

I have a layer with a couple of thousand points in it. I need to overlay an ellipse (740m * 1100m) over each point. Is there anyway to do this quickly opposed to manually placing ellipses over each ...
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12 votes
2 answers
2k views

Making ellipse based on ellipse-like polygon in QGIS

In QGIS I have a layer that contains ellipse-like polygons as in the image. I need to convert them to ellipses. They come from a different data sources. These are all actually regular shapes that ...
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8 votes
1 answer
329 views

QGIS: Create polygon shapefile of ellipses from points using Geometry by expression tool

In QGIS 3.16.6 I need to create a polygon shapefile of ellipses from points. I am doing the following: Processing Toolbox -> Vector Geometry -> Geometry by expression Input layer - points_in....
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11 votes
3 answers
557 views

Calculating semi-major and semi-minor axis length of an ellipse in QGIS

I have a layer that contains ellipse-shaped geometries. The layer has projected CRS and there are also rotated ellipses in the layer. I couldn't find a tool or plugin related to semi-major and semi-...
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2 votes
0 answers
92 views

Fitting an ellipse within an irregular polygon shapefile

Can we fit ellipse in irregular polygon shapefile in QGIS like Find maximum radius of circle that will fit within an irregular polygon?
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2 votes
1 answer
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How to set the number of vertices by shape digitizing tool in QGIS 3?

Can we set the number of vertices of the created circle or ellipse. (e.g. a circle/ellipse with 24 or 36 vertices) I can use "add regular polygon and set the point #" for circle, but i don't ...
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3 votes
0 answers
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Adding direction and lengths of semi-major axes of ellipses to their attribute tables in ArcMap [closed]

I made a polygon shapefile with hundreds of ellipses (using the ellipse tool). I want to know their orientations and the lengths of their semi-major and semi-minor axes (and add these to their ...
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Draw ellipse based on values within an attribute table

I would like to be able to draw and ellipse on a map based on values within an attributes table. At the moment I have 6 transects at a site with values based on IQI (Infaunal Quality Index) values; ...
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1 answer
290 views

R: calculating overlap between two standard deviational ellipses

Aim Calculating the area of overlap of two standard deviational ellipses in R and work out their intersection and union. Tool to be used calc_sde() from the 'aspace' package: calc_sde() Question ...
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3 votes
1 answer
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Creating ellipse with SatScan output using QGIS

I need to use QGIS to create an ellipse employing a SatScan output with information on spatial risk clusters for the occurrence of an. The output contains the coordinates of the centroid point of ...
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Comparing 2 GPS location data files to find if any location from one file is within a specified elliptical region of a location from another

I have 2 CSV files with GPS coordinates. I want to check if there are any locations in the first file which are inside a specified elliptical region surrounded by each location in the 2nd file. The ...
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3 votes
0 answers
116 views

Drawing ellipses over a tile map server in PyQGIS?

I have a few ellipses, defined by a latitude, longitude, semi-major axis in nautical miles, semi-minor axis in nautical miles, and an orientation. I'm trying to render them over a Google Maps layer. ...
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3 votes
1 answer
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QGIS Advanced digitizing switch from Cartesian to Ellipse

I´m trying to draw a line per length, but I need to enter the length in the Ellipse value. Is there a way to switch the values in the length window in the advanced digitizing panel from Cartesian to ...
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0 answers
385 views

Transform ellipse representation from major/minor (meters) to degrees

I am given an ellipse represented by a quadruple (major, minor, center, azimuth) where major,minor are the ellips's axis length in meters, the center is the WGS84 coordinates of the ellipse's center ...
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2 votes
0 answers
871 views

standard for generating a geolocation error ellipse from lines of position/bearing

Given SEVERAL points, where each point is a line of bearing (LOB)/line of position, and thus each point consists of a (1) latitude & (2) longitude position on the Earth's globe that this LOB is ...
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2 votes
2 answers
1k views

Drawing ellipse in OpenLayers

How to draw ellipse in OpenLayers? I have not problems with drawing circles, or MultiPolygons, but i need to draw simple ellipse and not found any functions for this action.
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2 votes
1 answer
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How to fit an ellipse around a polygon?

I'm using ArcMap to draw polygons around some geologic features. I want to know the length of the semi major and semi minor axes of the smallest ellipse that would fit around the polygons. I'm a new ...
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10 votes
2 answers
9k views

Drawing ellipse with shapely

How do I draw an ellipse with shapely?
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0 votes
0 answers
457 views

How to draw an ellipse around polygon?

I am trying to ellipses around polygons I have in im map, in ArcGIS 10.4. This what I need in the further steps for displacement of polygons. These polygons are from a geologic map and these specific ...
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2 votes
1 answer
1k views

Standard Deviational Ellipse with Open Source Python (GDAL/OGR etc)

I am trying to mimic the Standard Deviational Ellipse tool from ArcGIS through Open Source Python avenues. The formula is here. At the moment I am failing to get the correct X and Y axis lengths for ...
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4 votes
2 answers
932 views

PostGIS Ellipse Issue

I am trying to create ellipses from fields in my posgres table. I found this custom Ellipse function and have been trying to tweak it to meet my needs. Create Ellipse (x,y,rx,ry,rotation,#of segments ...
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1 vote
0 answers
374 views

How do I get imported KML circles to appear as circles rather than ellipses in QGIS?

I have a QGIS project, CRS is WGS84 (EPSG 4326). I have OpenStreetMap as the base layer. I have loaded some point features. I have created a buffer zone around some of these features with WGS84 as ...
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2 votes
1 answer
395 views

Creating ellipse with azimuth according to projected North not to geodetic North with ArcGIS Tool Table to Ellipse?

Table to Ellipse allows the user to create ellipses according to self-defined parameters. One of those parameters is azimuth. As written in the tool help the azimuth refers to the angle 0°-360° ...
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5 votes
1 answer
256 views

Create Two Ellipse/Arcs from Straight Line Segments

I have thousands of straight line segments (all separate features). I need to convert each straight line segment into two arcs, with the arcs opposite of each other. For example, I used the XY to Line ...
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3 votes
1 answer
287 views

Concentric Ellipses around polygons as a representation of density

I have someone who has given me a thumbnail of a map with some concentric ellipsoids placed in estimated high density locations for our business. One location has three, and two other location have ...
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1 vote
0 answers
423 views

Creating Ellipse in WGS84 with metric parameters [duplicate]

I have points in WGS84 (x,y), radiuses in meters (rx, ry), rotation angle in degrees. I would like to create a new WGS84 geometry. I've tried this but the major/minor distances seem to be off by a ...
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7 votes
1 answer
263 views

Generating series of ellipses on line using ArcGIS Desktop?

I am trying to create a series of ellipses (mocked up in green below) of defined dimensions along a line. I have got as far as generating regularly spaced points along the line that are attributed ...
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5 votes
0 answers
365 views

Creating ellipse around line in 3D space using PostGIS

In Postgis 2.1.1, I have a line in 3 dimensional space connecting two antenna points on the earth's surface. Is it possible to create an ellipse around that line? I have a formula to compute the ...
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1 vote
0 answers
386 views

Creating Irregular ellipses using SQL Spatial 2012 Geometry

I have stumbled across a problem in SQL Server 2012 - whereby I need to create different shape ellipses from the following data points: centre_x | centre_y | max_x | max_y | min_x | min_y I have ...
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9 votes
2 answers
2k views

Generating true curve elliptical polygons in file geodatabase using ArcPy?

As background, this question arose from trying to answer a question on How to generate overlapping polygons from lines output from Table To Ellipse tool? Using the ArcMap 10.1 GUI it is very easy to ...
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4 votes
1 answer
4k views

Drawing Ellipse with OpenLayers

I am trying to draw ellipse on the client side using openlayers with some mathematical functions from drawing ellipse with svg. I have achieved drawing it but not rotation what I have written for ...
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