Round World Projections

[+Mr. Wilson & a Mt. Goat]

Working on some caches and need my projections to be "Round World", is there a website that can do this?

[+Viajero Perdido]

I'd love to know too.

 

I need something with extremely high precision (more than my Garmin can manage), and I don't want to download a Windows executable (no matter how well-regarded the product & author may be) just to solve a puzzle.

[+Capt. Bob]

Try this Fizzycalc

[+user13371]

Why is it that the first two posters specified they wanted an online calculator rather than downloading a windows program, but the first suggestion someone made then was to download a windows program?

Edited April 11, 2011 by Portland Cyclist

[+ecanderson]

Why is it that the first two posters specified they wanted an online calculator rather than downloading a windows program, but the first suggestion someone made after that was to download a windows program?

Possibly because poster #3 is a pragmatist.

[+Viajero Perdido]

Windows executables: all the hazards of sex, without the fun.

 

VMware is my condom.

[+Red90]

I'd love to know too.

 

I need something with extremely high precision (more than my Garmin can manage), and I don't want to download a Windows executable (no matter how well-regarded the product & author may be) just to solve a puzzle.

 

Which do you want? The Garmin programs and GPS already use "round world", i.e. spherical projections. More accurate are ellipsoid projections. There are many apps for that. If you like to be in control...let me know. I have a spreadsheet that have the both types of projections built in.

 

With caching, it is important that both the owner and finder use the same projection methods.

Edited April 11, 2011 by Red90

[+EScout]

Why is it that the first two posters specified they wanted an online calculator rather than downloading a windows program, but the first suggestion someone made then was to download a windows program?

The suggestion is a good one because Fizzycalc is a small, easy to use program that is a nice tool for geocachers and other navigators. It has been mentioned on this site and used by the geocachers here for many years. It is one of my essential apps. If it was also an Android app, I would use it. (For Android, projections are in the app: "GeoCache Calculator")

 

For online, use: GPS Visualizer

This site uses the ellipsoidal model in its calculations. Vincenty ellipsoidal formula compared with spherical

 

If you are in the field solving a projection, use the projection feature on your GPSr, if it has one. Different GPSrs may one or the other model in their calculations, but at short distances it will be good enough.

[+Red90]

If you are in the field solving a projection, use the projection feature on your GPSr, if it has one. Different GPSrs may one or the other model in their calculations, but at short distances it will be good enough.

 

Every GPS I have tested uses spherical projections. The error can be up to around 0.3%. So at 10 km, your error can be up to 30 meters.

[+user13371]

I know fizzycalc is good stuff - I just laughed because whenever someone says "I want Y and don't want X" around here, the first suggestion is often "Get X."

 

The only advantage I could see for a website over a downloaded program would be sometimes being able to run the calculations in the field from a smart phone instead of taking along your pc/laptop/netbook.

[+Capt. Bob]

I know fizzycalc is good stuff - I just laughed because whenever someone says "I want Y and don't want X" around here, the first suggestion is often "Get X."

 

For a real good laugh try this:

 

Projection by calculator

 

[input starting Latitude in degrees and minutes]

Lbl 1:Deg:"LAD="?→A:"LAM="?→B:

[input starting Longitude in degrees and minutes]

"LOD="?→C:"LOM="?→D:

(Convert minutes to decimal degrees and add to degrees)

A+( B ÷ 60)→A:C+( D ÷ 60)→C:

[input Bearing and Distance]

"BEAR="?→H:"DIST="?→D:

[Calculate the distance components]

D x cos H→E:D x sin H→F:

[Convert distance components to degrees and add to starting coordinates

(E÷364566) + A→E:F÷(364566 x cos A) + C→F:

[Display Latitude degrees]

Fix 0:"N":Int A¬

[Convert decimal degree to minutes and display Latitude minutes]

Fix 3:(E-Int A) x 60¬

[Display Longitude degrees]

Fix 0: "W":-Int C¬

[Covert decimal degrees to minutes and display Longitude minutes]

Fix 3:-(F-Int C) x 60¬

[Repeat program]

Goto 1

[+EScout]

If you are in the field solving a projection, use the projection feature on your GPSr, if it has one. Different GPSrs may one or the other model in their calculations, but at short distances it will be good enough.

 

Every GPS I have tested uses spherical projections. The error can be up to around 0.3%. So at 10 km, your error can be up to 30 meters.

I tested four of my GPSrs, and two use spherical, two use ellipsoidal models, another does not do projections.

For the short distances of the projections used in three of my cache hides, it does not matter which your GPSr uses.

[+Red90]

For the short distances of the projections used in three of my cache hides, it does not matter which your GPSr uses.

 

Strangely enough, your cache hides are not the only ones in the world.

[+Rotareneg]

I'm surprised nobody mentioned this one: http://www.ngs.noaa.gov/TOOLS/Inv_Fwd/Inv_Fwd.html

 

There's a downloadable program and a web version.

[+EScout]

For the short distances of the projections used in three of my cache hides, it does not matter which your GPSr uses.

 

Strangely enough, your cache hides are not the only ones in the world.

The point I was making is that most navigational multi-caches are a fun walk in the park. The distances are typically small, and the difference between the models are insignificant.

REd90, if you are hiding a navigational multi-cache with points over long distances, where the model used for the projection is significant, then you should specify which model was used, just as you should specify whether using true or magnetic north reference.

[+janandsteve]

..... and I don't want to download a Windows executable (no matter how well-regarded the product & author may be).....

 

client-side JavaScript anyone?

[+Viajero Perdido]

I'm surprised nobody mentioned this one: http://www.ngs.noaa....wd/Inv_Fwd.html

 

There's a downloadable program and a web version.

Bingo - that worked for my problem.

 

Bookmarked. Thanks!

[+Red90]

REd90, if you are hiding a navigational multi-cache with points over long distances, where the model used for the projection is significant, then you should specify which model was used, just as you should specify whether using true or magnetic north reference.

 

Wow, I wish I had thought of that!!

With caching, it is important that both the owner and finder use the same projection methods.

[+Mr. Wilson & a Mt. Goat]

Figured out how to do what I was trying to find out all along: turn off the "terrain" layer in google earth and the world becomes "round".