Challenge #67: Calculate Spatial Angles

The solution to last week's challenge can be found HERE.

This week, we get back to spatial! A wireless carrier wants to geolocate or triangulate the location of a device/user based on the location of nearby cell towers and the device/user by determining the azimuth. As a result, they would like to calculate the angle (in degrees) between two points where a line is drawn from the lower point directly horizontally towards the other point.

Bonus: Try solving one way with the spatial tools, and another using no spatial tools!

challenge_67_start_file.yxmd

challenge_67_solution.yxmd

Spatial Analysis

Preparation

Advanced

Intermediate

Transform

Spatial

Accepted answers

All comments

NicoleJohnson

My solution, two ways - one with spatial tools, one without!

PS. Holy trigonometry, I had to dig deep for that one. My high school self is very disappointed with me right now for apparently forgetting everything I once knew about calculating angles...

Spoiler

challenge_67_NicoleJohnson.yxmd

alex

I used a couple more tools than @NicoleJohnson to calculate all the distances and angles, but came away with the solution in both formats. Another Masonic image transposed onto the DC landscape :>

Spoiler

challenge_67_AC.yxmd

MarqueeCrew

I got to the same answer as @NicoleJohnson, but stopped after getting the right result. I get no dessert.

Cheers,

Mark

challenge_67_MarqueeCrew.yxmd

MinaGO

Oh gosh my way is super hackish and I didnt know how to do the bonus. I've had a look and there are definitely a lot of spatial features I am not familiar with, especially the functions, nice to learn from other's answers.

Spoiler

challenge_67_start_file.yxmd

SeanAdams

So - full credit goes to this site which explained the full math of the great circle distance; provided pseudo code in Java / excel formulas; etc. http://www.movable-type.co.uk/scripts/latlong.html

I fully admit I don't understand the derivation of these formulae, but at least a little smarter now on how to use some of the trig & distance functions in Alteryx

This solution contains both spatial & basic trig version, and the non-spatial calculates both distance and angle fully using trig.

To @NicoleJohnson 's point - who would have ever thought that a subject like "Math" would come in useful one day...

Possibly one-day, I may find a good use for some of the other subjects we did in school like accounting; computer science; Inglish Wrting; etc. :-)

Spoiler

challenge_67_SeanSolution.yxmd

Natasha

Hopefully, my spatial solution will count as spatial since I used only one spatial tool.

I also have to admit a trigonometry defeat as I am sure 16 formulas were unnecessary and the answer I got was anyway smaller by ~1,5 degrees. That being sad, my spacial answer is also a bit off but I guess it can be a rounding error.

Spoiler

challenge_67_NK_1.yxmd

JoeM

The solution for Challenge #67 is posted! I'm sorry if is exacerbated any negative feelings around having to recall some highschool trig for that bonus.

estherb47

Haven't solved it without the spatial tools yet. Here's my solution with the spatial tools. Nothing very creative.

challenge_67_EHB_solution.yxmd

jacob

I got both ways and pushed me to do only the angle calculation in a formula tool in my spatial solution

Spoiler

challenge_67_j.yxmd

NaiLo

I managed to get the same result, but I didn't want to post because I couldn't figure out why I was calculating angle due East instead of North. The solution clarified it, definitely need to brush up on my trig!

Spoiler

challenge_67_NL.yxmd

LordNeilLord

I was using the calculations from here: http://www.edwilliams.org/avform.htm but I got stuck on the "angle" luckily the solution provided by @NaiLo held the answer

Spoiler

challenge_67_LNL.yxmd

patrick_digan

Spoiler

I didn't know the distance tool could output the degrees!

challenge_67_start_file.yxmd

EmanueleE

I know.... I'm late!!!

Spoiler

challenge_67_start_file.yxzp

ggruccio

Simple spatial exercise

challenge_67_gg_finish.yxmd

samN

phew, spatial tools saving me from remembering my trig.

challenge_67.yxmd

LandonG

Solution attached.

challenge_67_start_file.yxmd

philipmannering

Solution attached.

Spoiler

Easy with the spatial tools. No need for your maths.

challenge_67 - Calculate Distance and Bearing.yxmd

jamielaird

Solution using spatial tools attached.

Spoiler

challenge_67_solution_JL.yxmd

jasperlch

Solution attached.

challenge_67_JL.yxmd

derekbelyea

Spoiler

challenge_67_JDB_AnalytixStudio.yxmd

JosephSerpis

Challenge Completed

Challenge_67_Joe_Serpis.yxmd

CHarrison

My solution

Challenge 67.yxmd

dsmdavid

Just realized there was a "bonus" part of the question. Will come back to it later.

Spoiler

solved#67.yxmd

daniel_ferreira

Follow my solution attached...

challenge_67_solved.yxmd

StevenBetts

I solved this using the spatial tools (and a crowbar!) a couple of weeks ago but I left the non-spatial aspect of the challenge to come back to when I'd had more experience with Alteryx.

I now see my initial solution was needlessly over-complicated so I figured out a better way to do it, as well as solved the non-spatial tool method. I enjoyed working with the spatial expressions!

I left in my first pop at this challenge for everyone's amusement.

Spoiler

challenge_67_start_file_SMB.yxmd

kat

After much too much frustration over trigonometry and not remembering things, I finally figured it out. Moments after, I remembered the spatial tool that could so easily do this for me! So here are both ways.

Spoiler

Challenge #67.yxmd

danilang

Ha! Trig. And high school was so very, very long ago!

Spoiler

Dan

challenge_67_solution_DL.yxmd

Aster

Spoiler

My workflow:
67 workflow.png

Illustrative:
67 illustrative.png
Please ignore the unnecessarily complex workaround I used to build point C in spatial tools, and the fact that I did not consider the situation when point A may not be the vertex. My two questions are:
1. In the "without spatial tools" part I extracted the coordinates as Double fields and calculate the length of AC and BC with ST_Length and CreatePoints. Then I used ArcTan(BC/AC) to determine Angle A, which turned out to be slightly different from the output from spatial tools (31.592 instead of 31.607). Could anyone tell me why and how to fix it?
(My assumption is the loss of accuracy when I try to put the coordinates in a Double field)

2. Initially I tried to calculate AC and BC by subtracting coordinates (i.e. Length of AC=Abs([X coordinate of A]-[X coordinate of B]) and naturally got the wrong results, which led me to the question: what are these coordinates used in building spatial objects? Are they longitudes and latitudes, and the positive/negative numbers tell West vs East, and North vs South? Is my assumption correct?

I have finished this but have two questions, could someone kindly provide some pointers here? Thanks!

(Please see inside spoiler)

challenge_67_start_file - Aster.yxmd

Ruud

My solution.

challenge_67_ruud.yxmd

KOBoyle

Solution attached. @Aster I too encountered an inconsistency with my formula based solution. See the spoiler for more details.

Spoiler

I used the ACOS function and got 31.55 vs. 31.61 using ASIN. In the solution I was that the distance for all three sides were calculated, so I added two more formulas. ASIN, ACOS and ATAN return a different result in degrees.