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1
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0answers
29 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 ...
1
vote
0answers
43 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 ...
8
votes
3answers
738 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 ...
2
votes
0answers
33 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 ...
0
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0answers
29 views

Is there a way to convert L.circle to a geodesic polygon in Leaflet

Reference: How to make a predetermined Polygon (Circle) From 4 Coordinates, The Radius and Center Longitude and Latitude in Openlayers Openlayers uses this function : createGeodesicPolygon Question: ...
2
votes
3answers
105 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 ...
0
votes
0answers
114 views

Why does ArcGIS 10 Buffer not provide accurate geodesic buffer?

I created a shapefile following these criteria as recommended for Performing Geodesic Buffering: The input feature class must be a point or multipoint dataset. (shapefile is a point) The input ...
2
votes
0answers
304 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 ...
4
votes
4answers
369 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 ...
2
votes
0answers
310 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 a question on how to create a Polyline Buffer ...
13
votes
4answers
289 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 - ...
6
votes
3answers
521 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 ...
12
votes
2answers
3k 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 ...