Scientific discipline dealing with the measurement and representation of the Earth's shape and gravitational field.

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3answers
2k views

Local Coordinate to Geocentric

The ultimate question, I need a transformation matrix to take a point in local space representing a roughly 500m x 500m place in New Mexico centered at -108.619987456 long 36.234600064 lat. The final ...
20
votes
6answers
12k views

Trilateration using 3 latitude and longitude points, and 3 distances

I want to find out an unknown target location (latitude and longitude co-ordinates). There are 3 known points (latitude and longitude co-ordinate pairs) and for each point a distance in kilometers to ...
2
votes
2answers
2k views

How to perform trilateration using 3 lat/lon points without distances?

I read this thread Trilateration using 3 latitude and longitude points, and 3 distances explaining about trilateration using 3 latitude and longitude with measured distance. The problem is I want to ...
11
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2answers
6k views

How do you compute the earth's radius at a given geodetic latitude?

(I see there is an equation on wikipedia that does exactly what I am asking but there is no references. I have no way of confirming the validity of this equation!) I already understand the difference ...
7
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1answer
174 views

Which training courses in Geodetics can you recommend?

Can anyone recommend any training courses in geodesy which would cover the following objectives: Case studies on coordinate issues Overview of geodetic datums, coordinate reference systems and ...
3
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1answer
145 views

New coordinate system?

I just had my mind blown in answer to my previous question. I was going to rework that question, but decided it makes more sense to ask a new one. I had been converting between ECEF and lat/lon, and ...
21
votes
3answers
481 views

Are ellipsoids a mathematical necessity?

The literature usually just tells us that the Geoid is complex to describe mathematically and that we therefore fit different Ellipsoids to approximate it. Are these Ellipsoids mathematically ...
6
votes
3answers
579 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 ...
3
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1answer
145 views

Why not measure elevation from the center of the earth?

In trying to understand Geoid vs Ellipsoid height, I ran across this page. One of the claims is: Zero elevation as defined by Spain is not the same zero elevation defined by Canada ...
12
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2answers
635 views

How do you find a lat/lon (DMS) on a paper map using a 30cm ruler?

How do you use a 30cm ruler to find DMS on a paper map? The locations I would like to find are the 'corner' points so I can generate an extent based on the four corners. I have an old paper map (3 ...
1
vote
0answers
31 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 ...
1
vote
0answers
116 views

Intersection between a ray from lat, lon, alt, with pan, tilt and earth's surface

I have a problem that consists of finding the intersection point between a ray from a given lat, lon, alt, that is looking to a given pan and tilt angles and the earth's surface. I need the lat, lon ...
1
vote
1answer
361 views

Long range Trilateration from 3 lat, long, range

I've been looking at the following solution to a similar problem Trilateration using 3 latitude and longitude points, and 3 distances However with my problem the 3 points are spread over a large ...
1
vote
1answer
103 views

Which SRS is computational more effective to store continental scale data? (given some conditions)

For a Precision Agriculture application I need to make calculations in UTM projection. The data will be stored in Postgis and is made of soil samples results (point data) and field boundaries of many ...