# Questions tagged [geodesy]

The measurement and representation of the Earth, its shape and gravitational field, distances on the Earth, and coordinate systems for locating points on it including longitude and latitude.

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### How to calculate distance of a point from a rhumb line (crosstrack deviation)

Is there any known closed-form or non-iterative way to calculate or approximate the distance of a point from a rhumb line? (i.e. how to find crosstrack deviation from a rhumb line)
62 views

### Given two points with 3D coordinates, and three angle observations, how to caculate the coordinate of the third point

Given two points, $M_1(X_1,Y_1,Z_1)$ and $M_2(X_2,Y_2,Z_2)$,$P(X_p, Y_p,Z_p)$ is the unknown point. How to get the coordinates of $P$ by three angle observation . The picture below displays the ...
30 views

### Definition of constant-curvature curve embedded on an Ellipsoid of revolution

I am interested in identifying a type of curve so I can do literature review on it. What is the name of a curve embedded on an ellipsoid of revolution in which the curvature of the embedded curve is ...
139 views

### Normal vector to ellisoid surface

How do I obtain a normal vector to the surface of an ellisoid, at a given latitude and longitude. Getting the same normal vector for a sphere is trivial.
23 views

### how to discretize the geodetic of the paraboloid with euler forward?

I have Paraboloid hiperbolic, parametrizade by (u,v,uv) Operating with the geodesic equation, i have obtained enter image description here But I do not know how to place the obtained in euler ...
212 views

### Understanding differences in Geodetic (WGS84) to ECEF equations?

Methods suggested in this, that and there all recommend the following: $$x = R \cos(\theta) \cos(\phi)$$ $$y = R \cos(\theta) \sin(\phi)$$ $$z = R \sin(\theta),$$ where latitude is $\theta$, ...
86 views

### Cartesian Coordinates to Geo Position [closed]

Having $(lat, lon)$ I used the following formulae to convert it to Cartesian \begin{align} x & = R \cos(lat) \cos(lon)\\ y &= R \cos(lat) \sin(lon) \end{align} Now, I need to convert x,y ...
260 views

112 views

### How much extra sea water is needed?

We might call this the “Noah's Ark” calculation, but in the movie Waterworld (1995) they have the icecaps melting and take poetic license making the ~$220$ feet or so of sea water (one estimate I've ...
238 views

### Find Latitude of point given Longitude and Great Circle orientation

Given the orientation of a great circle as the cartesian components of the normal vector $(a,b,c)$ to its plane, i.e. all points on the circle described in Earth-Centered Earth-Fixed (ECEF) ...
172 views

### Cartesian to geodetic conversion of 3D bounding box - How to calculate latitude and longitude from an axis aligned bounding box

I have a geometry with its vertices in cartesian coordinates. These cartesian coordinates are the ECEF(Earth centred earth fixed) coordinates. This geometry is actually present on an ellipsoidal model ...
328 views

### Calculate a point on a geodesic line on an ellipsoid

I have a problem which i don't understand how to achieve. Maybe someone could sheed some light on it. Have a look at this picture: What I try to achieve is to determine the point D on the geodesic ...
309 views

### Algorithm for Stepping Through Latitude, Longitude and Height with a Heading

I have a function which reads in latitude, longitude, height, heading and step size. My function should calculate the latitude, longitude and height of the position one step size away in the direction ...
459 views

### Seasonal changes in hours of daylight

I will post my own answer to this question unless someone else posts the same answer first, but I am curious to know what other points of view might lead to different ways of answering it. ...
12k views

### Different ways for calculating distance between two geodetic points give me different results

I'm trying to calculate the distance between two geodetic points in two different ways. The points are: A:(41.466138, 15.547839) B:(41.467216, 15.547025) The ...
221 views

### Circle-circle intersection on a spheroid

Does anybody have formulae to solve the following issue. If you have two circles, defined by their two centres, and a radius for each circle. Where (if the circles intersect) are the two points ...
822 views

### Drawing a Great Circle between two given points on Earth

I need to draw a great circle arc between two latitude and longitude points. For sake of example we will use the coordinates for LAX and JFK. JFK is 40.64°N / 73.78°W LAX is 33.94°N / 118.41°W My ...
750 views

### Maximum latitude of a great circle

1 - I am trying to figure out the longitude at which a geodetic great circle reaches its apex. (I have a point and the azimuth at that point identifying the circle) I have found a good resource that ...
620 views

### Distances are different by ~100-200m

I'm measuring distance of 2 points on Google Map and then in my program converting them into ECEF using this formula. Then using Pythagorean theorem to calculate distance between those 2 points. ...
127 views

### What property does this equation calculate?

It's pretty difficult to Google for the meaning of a formula. This is the equation, it has to do with ellipses and GIS coordinates. $$\nu =\frac{ a} {\sqrt{(1 - (e^2 \cdot \sin(\varphi))^2)}}$$ $a$ ...
I would like to divide the globe into 1000 $\times$ 1000 meter geodesic squares, and then map any long / lat to the applicable square. The altitude of each block would be the altitude of the earth at ...