Questions tagged [great-circle]

Any line bisecting the surface of a sphere into two equal halves.

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How to find out if three points on Earth are on the same great circle?

I am trying to figure out whether 3 particular points on Earth's surface are on the same arc (of a great circle) or not. Using Google Earth's (also ArcGIS Earth's) line tool, I see that the points are ...
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1 vote
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How to illustrate geodesic line reflecting bearing between two points + third projected point

I'm using Spatialite + ST_Project to extrapolate a line with an implied bearing between two points to some distance beyond those two points. Here's an example sql snippet: SELECT AsGeoJSON(ST_Project( ...
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Code for optimizing great circle flight paths

Is there any app or available code that can answer questions of the following type: Find the great circle that: intersects the most land? whose longest leg over water is the shortest? intersects the ...
110 views

Labelling contour lines along a great circle

I'd really like to show the satellite zenith angle as seen from an observer on the ground. I can calculate everything just fine and get a graph that is useful and passable. import numpy as np import ...
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PostGIS Splitting complex linestring over dateline

I have complex linestrings in PostgreSQL (see sample below). Many of these linestrings will cross the international date line (longitude 180 / longitude -180). The problem is that PostGIS assumes ...
126 views

find points on arc for shortest distance between two locations

I have two points on the earth. The shortest path between these two points forms an arc. How do I find the points that represent this arc? Bonus points if you can help with an answer in regards to an ...
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Creating Great Circle Line from Two Points

I am trying to create a great circle line in order to ascertain if one was looking 'straight-out' from the end of a pier what country/place they would be viewing. I have the below PostGIS code written:...
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Why ellipsoidal distance measured in EPSG:7030 in QGIS?

I measure distance (km) in QGIS (Ctrl+Shift+M) . In Ellipsoidal, it using CSR EPSG:7030. In Cartesian, they didn't say what projection is used. If it using ellipsoidal option, does it mean measured ...
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Least-cost path = great-circle path in open ocean? (R) (gdistance)

I'm using R and the gdistance package to generate the shortest routes in the ocean. In the open ocean with no obstacles, the least-cost path should equal the great-circle path. But I can't seem to get ...
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Concept behind longitudes

Why longitudes are not parallel and why do they meet at the poles? What problem would have happened if like latitudes they were parallel circles running from west to east? I would request the ...
1 vote
778 views

Calculating distances with PROJ4J

I am already using proj4j in my project to convert between different coordinate reference systems. (Internally I use WGS84 but some sources supply data in a different CRS.) Now I need to calculate ...
• 271
1 vote
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Calculate way points between departure and destination

I am working on an aviation project, in which I need to plot a great circle route between departure and destination airports. Here is a static JSON structure I am using, where the user enters KBTP as ...
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Plotting great circle lines in Cesium (just getting started)?

How does one plot Great circle lines in Cesium (3D, not 2D) using the WGS84 ellipsoid? I found something like this in another thread but I'm having trouble applying it to my application (simply ...
• 151
1 vote
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Error in mapping connections with great circles [closed]

I am fairly new to R and to map plotting. I am trying to overlay some network information on a world map. I loaded a shapefile from Natural Earth as a large SpatialPolygonsDataFrame via readOGR. I ...
235 views

Distance between coordinates computation speed: conversion to UTM vs Great Circle

For a program I am writing I need to calculate the distances between coordinates. Seeing as I need to perform a large number of these calculations for each coordinate (thousands) it makes sense to ...
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Interpolating orthodrome between two (lon,lat) points in Python?

I have a polygon that consists of a few (lon, lat) points, each pair of consequent points is considered to be connected by orthodromes. I want to interpolate the polygon with some extra points between ...
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St_Segmentize on CARTO

I need help with the phrasing of this query. I am applying this in CARTO to a file with lines. The following query does not generate a curve as expected. I am new to SQL/PostGIS. select mycartoid....
4k views

Iterate over geopandas dataframe returning nearest point on each LineString

I'd like to iterate through a GeoDataFrame that contains a column of LineStrings and return a list of points; one from each LineString that is closest to a reference point. #### . Import data from ...
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Great circle rendering of satellite ground tracks reversed in southern hemisphere

I'm working on rendering some satellite ground tracks from postgis, through geoserver, and onto openlayers. The python library I'm using to get lat, lon from TLE data isn't perfect, so there are ...
• 117
1 vote
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Drawing curved lines in Carto?

I have a dataset that has the following structure: City_Start / Lat_City_Start / Long_City_Start / City_Dest / Lat_City_Dest / Long_City_Dest What I want to do is create a curved line between those ...
2k views

Formula for the great circle arc between two points (lng/lat coordinates)

I am trying to animate a point moving from one location to another on a map. And I would like the point to travel along the great circle arc between the locations, rather than in a straight line. ...
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Calculating distance between two Lat Long points with different altitudes? [closed]

If we assume that the altitude is held constant, the great circle distance is correct. However if the radius of the circle is not constant how can the distance be calculated? In my case the altitude ...
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Calculate Great Circle Distance between two point layers via way point

I need to create three distance matrices for around 550 points spread throughout Africa, Europe and Asia. The first matrix represents great circle distances, the second is the shortest distance along ...
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1 vote
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Recommendation for a book for geographical distance calculations [closed]

I am currently writing my Thesis and I need a book covering the geographical distance calculation like haversine and Vincenty. Since I am not of this field, I can't find books which might help me ...
1 vote
3k views

How to calculate straight line distance from spherical distance

I have longtitude and lattitude coordinates of one point and spherical distance between this and another point on Earth in kilometers (the shortest distance over the earth’s surface). I need to ...
1 vote
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Confusion regarding distance calculation in R (euclidean distance, "great circle distance")

OK so considering these two cases: ln1<-SpatialLinesDataFrame(SpatialLines(list(Lines(Line(matrix(c(53.3604464,53.36062,-6.2424442, -6.242413),ncol=2)),ID="a"))),data=data.frame(dummy="a"),match....
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Projecting Cross-Track distance on great Circle?

I have a route formed by some waypoints (black path) and I would like to project it over the great circle (blue path) connecting the starting and ending waypoint. With the work "project" I mean to ...
1k views

How to create Great Circle Mapper style range rings in QGIS?

I'm trying to figure out how to create a range ring from some location (e.g. Broome Airport "YBRM") in QGIS that looks like something in Great Circle Mapper. The issue is about how the range ring ...
• 509
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How a draw a circle (on the surface of earth) on a mercator projection?

I would like to use R and leaflet to draw a circle (a real circle on the surface of the earth) on a mercator projection. In the following code, I have the center of the circle (with lng=0 and lat=60),...
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Making Great Circle Arcs which look good on Web Mercator map?

I'm trying to create a map, with data indicating some flights, and want to use Great Circle Arcs, to connect the source and destinations. Basically, I want to do something similar to the famous ...
401 views

Great circles path not curved (in R)? Conventions and convertions problems?

I am given the great circle equations of two paths. The first one is Longitude = 168 degree. and the second one is: tan(Lattitude)=.11 cos(Longitude) + .64 sin(Longitude) However, I am not ...
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Which projection can I use to see alignments on great circles?

I want to put on a QGIS map some historical sites to check if they are aligned. If an alignement exists, the points should stay on a great circle (is this correct?). I want to visually verify this ...
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Is there any online viewer which displays the polygons assuming great circle lines for the edges?

My question is similar to this one: Are there any online WKT editors? The links given in answers have been very useful to me. However, it seems that when the tools in question display maps, they ...
3k views

Project location on a (great circle) path

I've been searching this SE site for quite a few hours now, and I'm still struggling to find a solution to my question. My goal is that given a way in OSM and my location (lat/lon coordinates), I want ...
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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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Great circles in QGIS and export in 3857 web map

My plan is to visualize great circles in a Leaflet web map. So coming from this great postgis article and R version I thought it would work like this in QGIS: create a line from two points, store ...
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Find latitude of point on great circle given longitude

I am trying to find out wether my implementation has faults and/or if there is a better method. The problem: Given two points (Lat/Long) defined over the WGS84 ellipsoid, find the point lying on the ...
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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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How to prevent cross-world lines in ggplot world map?

I'm having issues displaying 'great circles' paths and polygons in ggmap, an extension of ggplot2. Please enter the following code to replicate my issues: https://gist.github.com/Robinlovelace/...
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cross track distance to great cicle line and rhumb line

How to calculate cross track distance to great cicle line and rhumb line? For great circle line, I've tried this formula, but it is not accurate while the distance is less than 0.1nm. For rhumb ...
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Google Earth / QGIS projection (great circle line)

Here is my question: 1- Based on a long distance segment ( approx 2000 km) drawn on Google Earth and imported as shapefile in QGIS I want to obtain a terrain profile based on "Terrain Profile" plugin....
• 31
940 views

Should geometries be drawn using rhumb-line or great-circle paths?

I work with WGS-84 coordinates and, most of the time, my map display (luciadmap) is in Mercator projection. My client is surprised to see that, for a rectangular geometry: the line between the 2 ...
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Drawing smooth great circle?

I want to draw smooth great circle in any scale and any distance on a Mercator map. The key problem here is how many intermedia points do I need for different location and distance to draw it smoothly ...
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Does PostGIS have a Vincenty Distance calculation?

I have compared some distance calculations between geopy and PostGIS ST_Distance_Sphere, and it seems that PostGIS ST_Distance uses a calculation that is similar to the great circle distance rather ...
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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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1 vote
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Draw great circle rays from a single point along specific directions

How can I draw great circle rays starting from a single given point P (for example, from coordinate [34 N, 116 W] in this map) and along directions D1, D2, ... (for example, 30, 45 and 135 degrees) in ...
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Can I cross the dateline in CartoDB?

I've created a lovely route map in CartoDB, but one of the lines crosses the dateline (from Colorado to Guam, FWIW) and finds its way there by hitting the dateline north of Alaska, bouncing back ...
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Difference between Vincenty and great-circle distance calculations?

Python's geopy package features two distance measurements techniques: Great Circle and Vincenty's formulae. >>> from geopy.distance import great_circle >>> from geopy.distance ...
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1 vote
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I've pulled together a series of maps in R based on Nathan Yau's excellent Great Circles tutorial and a nice zipcode package The maps show how many people from many zip codes descended on a single zip ...
• 655
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How to determine vector between two lat/lon points

For all the math geniuses out there...given two lat/lon points (point A and point B), what is the simplest way to find the vector needed to reach point B from point A. For example, the vector needed ...