# Altitude Azimuth To Xyz Homework

**azimutal coordinate system is referencing to NEH (geometric North East High(Up)) reference frame !!!**

in your link to image it is referencing to axis which is not true unless you are not rendering the world but doing some nonlinear graph-plot projection so which one it is?

btw here ECEF/WGS84 and NEH you can find out how to compute **NEH** for **WGS84**

As I can see you have bad computation between coordinates so just to be clear this is how it looks like:

on the left is global Earth view and one **NEH** computed for its position (its origin). In the middle is surface aligned side view and on the right is surface aligned top view. Blue magenta green are input azimutal coordinates, Brown are cartesian projections (where the coordinate is on its axis) so:

if you use different reference frame or axis orientations then change it accordingly ...

**constructing the view-port**

You need axis vectors and origin position. you already have (at least you think) and axis is the ray direction so you should have it too. Now just compute as alignment to something (else the view will rotate around the ray) I use NEH for that so:

To make it a valid view_port you have to:

You need inverse matrix computation for that

The question asks for conversion between spherical and cartesian coordinates. This spreadsheet lays out the formulas:

*Blue lines are input, black are intermediate calculations, and red are output. Within the formulas, the values are referred to by the names in the [Parameter] column (assigned via the Insert|Name|Create operation).*

They differ from those in most math/physics references because in geography, the azimuth is usually taken east of north rather than north of east. This makes the geographic azimuth the *complement* of the mathematical one (they sum to 90 degrees). Replacing an angle by its complement in any trig function interchanges it with its "co" partner: sine and cosine are interchanged, tangent and cotangent, secant and cosecant. Also, in many mathematical systems the "dip" is expressed as an angle from true vertical (a co-latitude) rather than as an angle from horizontal (a latitude), again causing an interchange of sine and cosine.

### Edit 9/20/13

For a downhole distance you probably want to negate .

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