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Questions tagged [geodesic]

A geodesic is the shortest path between two points on a curved surface; in this context applies to questions where the curved surface is the earth's surface.

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64 views

If rectangle corner points have same nearest neighbor, does whole interior?

If all four corners of a spherical (but actually WGS84/elliptical) rectangle are closest to a given point p in a set S, does that necessarily mean all points inside the rectangle are also closest to p?...
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1answer
39 views

Non-iterative algorithms for direct problem in the study of geodesic

I am finding an appropriate algorithm to implement in my program for direct problem in the study of geodesic. In brief, the direct problem deals with finding the end point (its longitude, latitude and ...
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26 views

Geodesic multiple ring buffer in ArcGIS

The Buffer tool in ArcGIS 10.5 allows for the creation of geodesic buffers, however, I am unable to find that option for the Multiple Ring Buffer. I have 10 areas around which I need to create 6 ...
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2answers
82 views

Converge origins on destination leaflet geodesic

I am using Tabletop.js to map locations on a leaflet map. With each row I add the lat lng to a feature group and then to the map. What I would also like to do is use leaflet geodesic to draw a line ...
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2answers
72 views

Calculate perimeter of a large polygon using geodesic calculations

How do I calculate perimeter of a large vector polygon (polygon set) which spans almost half the globe? I guess regular calculations do not produce accurate results in this case.
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2answers
63 views

Understanding geodesic envelope?

I've been looking at some various ways to calculate geodesics. One particularly good site collecting load of helpful information, is this one. There you can also find a link to a map that shows a ...
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0answers
74 views

Is there an open source library that offers geodesic buffering of large polygons?

I need to buffer some large polygons and minimize distortion. Is there an open source library that offers negative and positive geodesic buffering of large polygons? I am aware ESRI has an ...
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1answer
124 views

ArcGIS Point every 100 meters along poline

ArcObjects with ArcGis 10.1 I have constructed a polyline in WGS84 that has straight segments and curved segments. The line is heavily geodesically densified. Now I have to step through every 100 ...
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2answers
316 views

Calculate turn required to follow a line of latitude

Lines of latitude are not geodesic except at the equator. So to follow perfect eastern course in the northern hemisphere in a vehicle a left turn is constantly required. We can express a turn as the ...
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1answer
67 views

Finding crossing point between geodesic line and parallel?

Given a geodesic line (starting point and initial azimuth) is there an algorithm to find the longitude of the [first] crossing of a given parallel? I have already checked with Clairaut's constant ...
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1answer
515 views

Euclidean and Geodesic Buffering in R

In Understanding Geodesic Buffering, The Esri Geoprocessing Development Team distinguish between Euclidean and Geodesic Buffering. They conclude with "Euclidean buffering performed on projected ...
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1answer
63 views

Definition of “most northwesterly point” on a landmass?

If we are using a 2D representation of a landmass, with north represented as up and east as right, then we can conceptualise the most northwesterly point as being the last point we reach when we place ...
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1answer
217 views

Creating a geodetic line that goes around the whole ellipsoid with pyproj

https://jswhit.github.io/pyproj/pyproj.Geod-class.html Pyproj's Geod class has a npts method to create points on the geodesic between two points: npts(self, lon1, lat1, lon2, lat2, npts, radians=...
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1answer
188 views

ArcPy Insert cursor losing vertices when writing Polygon features?

I'm currently trying to code a geodesic buffer from points (the one that is implemented in ArcGIS is very slow). The idea is to calculate 100 point coordinates (P_Buffer) around an initial point (P) ...
2
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1answer
330 views

Hive GIS ST_GeodesicLengthWGS84 not returning expected distance

I am trying to find the distance between two points (in meters and not degrees) using GIS Tools for Hadoop by ESRI. The ST_Length provides distance in degrees and hence I used the ...
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2answers
388 views

What's wrong in using latitude and longitude as X and Y on a Cartesian space?

What can go wrong and what kind of error can build up if I use geodetic coordinates as if they were cartesian and place my objects into my world with no conversion formulas?
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2answers
235 views

JTS Vividsolutions API: compute First (direct) geodetic problem

I'm using the popular JTS Vividsolutions API for Java. I'm struggling to find if I can perform calculation of the First (direct) geodetic problem with the API. Is there a way to calculate this with ...
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0answers
410 views

Measuring Geodesic Distance in ArcGIS for Desktop? [closed]

I'm working with only a basic/student license for ArcGIS 10.1 on an ocean mapping project. I've created a grid that covers all ocean area, capturing various characteristics within that grid (the ...
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1answer
1k views

Get Radius in epsg 4326 with Openlayers 3

What is the best method for getting the radius of a circle in Openlayers 3 in epsg 4326 (geodesic)? I'm using this example for a base and trying to draw a circle while getting the radius, but using ...
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2answers
1k views

testing if a Geodesic polygon contains a point c++

I am looking for an algorithm, preferrably in C++, that can take a point (lon,lat) and determine whether that point is inside a geodesic polygon. Is there such an algorithm freely available?
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1answer
3k views

How to draw a circle in OpenLayers 2 and measure its radius dynamically?

With OpenLayers 2.13, I want to draw a circle and obtain its radius at each mousemove. The radius would then be returned as arguments of a callback function, for example. But of course, this is not ...
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1answer
718 views

Modifying straight line segments to follow geodesic / great circle paths using QGIS?

I have a kml file showing a dodecahedron stretched across the surfce of a globe, which I downloaded here: http://montalk.net/cgi-bin/coordinates.py I would like to re-project this dodecahedron so I ...
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1answer
184 views

Direct Geodesic with Point 2 Azimuth

I am trying to find a way to calculate the direct problem on the WGS-84 ellipsoid but instead of using the initial Azimuth (e.g. lat1, lon1, distance, fwd azi), I want to compute it with the reverse ...
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2answers
424 views

Moving dead ahead: rhumb line, great circle or none

I think I understand the whole rhumb line and great circle idea but I can't seem to find an answer on this question. Suppose I am driving a car (i don't use ship because I don't want to put the ...
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0answers
104 views

Calculate geographic position based on azimuth, distance and height [duplicate]

How to calculate the geographic position of an object in sky (Point B)(like an aircraft) from Home Point (Point A) based on only four variables: Lattitude and Longitude at Home Point, Azimuth at ...
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2answers
540 views

Alternatives to the Vincenty geodesic functions in OpenLayers 3?

I'm migrating an application from OpenLayers 2 which uses OpenLayers.Util.destinationVincenty() to compute the projected latitude and longitude of a point from an origin given an angle and distance in ...
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1answer
174 views

Prior art on rhumb line and great ellipse areas?

I'm adding the computation of the area betweeen a rhumb line or a great ellipse and the equator to GeographicLib. My formulations are briefly given in here and here. These formulations are similar ...
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2answers
793 views

How to validate OpenLayers area calculation using PostGIS?

I am working on a GIS API that work on top of OpenLayers. I have a feature that calculates the area of a drawn polygon. I have tested it on the browser and the areas I got, appear to be correct. For ...
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2answers
204 views

Which one of these azimuth values is the right one? And why?

First of all, let's make clear that I want the Azimuth on the surface of the Earth, i.e. the angle between two locations, for example New York and Moscow. I am testing some azimuth calculations with ...
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1answer
407 views

Is the Azimuth on the equator equal to the one not on the equator?

I am trying to fully understand the concept of Azimuth and I am encountering some inconsistencies (or maybe it is my error). I show you some examples that do not match, hoping somebody can explain me ...
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0answers
336 views

Air corridor in spherical surface: calculating great circle tangent points with small circles

I have the necessity to draw on a sphere (earth) an air corridor. In the cartesian plane, this corridor is made by some circles and from outer tangents that connect these circles as you can see in ...
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3answers
908 views

Geodesic measurements for short distances throughout US?

My ArcGIS experience has been limited to working on large-scale maps with planar projections. I'm moving to a project in which I want to calculate the distance between pro sports facilities throughout ...
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1answer
625 views

Buffer not providing accurate geodesic buffers in ArcGIS Desktop 10.0?

This appears to only be a problem when using ArcGIS Desktop 10.0. I created a shapefile following these criteria as recommended for Performing Geodesic Buffering: The input feature class must be a ...
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1answer
993 views

calculating bounding box from known centre coordinate and zoom

I have a map, the centre of that map (centrepoint) is = -37,175 ( gps) I know the zoom of the map = 13 I know the size = 320x320px I know there is 111111m in a degree of latitude and a varying degree ...
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4answers
1k views

How to compute geodesic area in GeoDjango?

I have some polygons which can be anywhere in the world. I would like to compute their areas. The GeoDjango docs for GEOSGeometry.area don't specify whether it is geometric or geodesic area, but ...
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0answers
553 views

Creating a Geodesic Polyline Buffer in OpenLayers

I have a feeling that the answer is going to be 'You can't do that without some very complex coding' but I thought I'd go for it anyway. I recently asked Creating Polyline Buffer in OpenLayers 2?, ...
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3answers
1k views

How to generate geodesic linestring from two points in C#

I'm looking for a FREE C# class, library or set of functions that will allow me to generate a geodesic linestring (or array of vertices, whatever) from two decimal degree points. I've found ...
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4answers
623 views

Are long lines in shapefiles to be considered geodesics or straight lines in the 2D latlong space?

Is there a definition on how lines connect vertices in the shapefile format? In the simplest case, imagine a line with only 2 points, from 40,-118 to 40,-112 - that's somewhere random in the US - ...
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3answers
914 views

What kinds of line segments/edges require high accuracy in a true surface-of-the-ellipsoid representation?

I've been musing (and doing prototype coding) for a 'projection free' geographic codebase with your basic point, line & polygon primitives. Rather than dealing with all the sacrifices that come ...
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2answers
5k views

Using Geodesic Measurements for Circle Radii?

I am currently developing an OpenLayers mapping site. Measurements can be made using a line tool, and an area tool. Both of these are currently set to calculate geodesic measurements as outlined in ...