Engineering Notes -- Home
			
						
			
			
			 A note from the author 
			
			As a practicing aerospace engineer, I frequently encounter problems that require math skills I don’t have and must learn.  Early in my career I adopted the habit of writing down the solutions to these problems in a personal Engineering Notebook.  If a problem took more than a trivial amount of time to research, and was general enough that I might run into it again some day, into the notebook it went.
			
The articles on this website are based on those engineering notes.  They represent practical, battle-tested solutions to real-world problems.  Technology changes, but math is eternal.  I hope these papers save you some time.
			
			
			
			
					
				
				
				
			
				
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					 Converting between Earth-Centered, Earth Fixed and Geodetic Coordinates
					      How to convert from Geodetic coordinates (latitude, longitude and height above ellipsoid) to Earth-Centered, Earth-Fixed coordinates, and back again. Includes example code.  | 
				
				
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					 Rotating Points in Two-Dimensions
					      The efficient way to rotate points around an arbitrary center on a two-dimensional Cartesian plane.  | 
				
			
				
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					 Rotations in Three-Dimensions: Euler Angles and Rotation Matrices
					      Describes a commonly used set of Tait-Bryan Euler angles, and shows how to convert from Euler angles to a rotation matrix and back.  | 
				
			
				
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					 Rotation Quaternions, and How to Use Them
					      An introduction to rotation quaternions.  Shows how to perform rotations, and how to convert between quaternions, rotation matrices, axis-angle, and Euler angles.  | 
				
			
				
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					 Solving 2x2, 3x3, 4x4 and 5x5 Systems of Linear Equations on a Computer
					      A general solution to systems of linear equations of up to 5 equations and 5 unknowns, using Cramer's Method.  | 
				
			
				
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					 Interpolation 
					      Methods for interpolating one-dimensional signals, images, and 2D graphics.  Based on Catmull-Rom cubic spline.  | 
				
			
                
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					 Rigid-Body Image Registration 
					      A tiepoint-based error-minimization method for registering two images, where the degrees of freedom are limited to translation, rotation and scale.  | 
				
			
			
		
			
			
			
				
			
			
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