Lat./Lon. confussion

[Guest GuyMcBeerdrinker]

I'm confussed about a couple of things. Now, I understand that there are different formats for locations (UTM, WSG, etc.) so maybe I'm just confussing them. This is what I've been able to figure out on my own, someone correct me if I'm wrong.

 

If you visualize the globe as flat, then Greenwich is the orgin, meaning its at x=0 and y=0, so anything to the left of it on the horizontal axis is negative (W Latitudes), and anything bellow it on the vertical axis (S Longitudes) is negative and vice versa...pretty obvious. My question is, what are the ranges in degrees of lon. and lat. I'm assuming that they range from W or E 0 to 180 degrees and N or S 0 to 90 degrees, is that correct?

 

My confussion comes when I see something like this -2.393.91. The way I see it, its E002.393.... its pretty obvious that you can't have a 200 degree eastern latitude because its greater than 180 degrees. But, my problem is that I don't know if 91 seconds as in ...091 or if it is 910 as in ...910, because it seems that GPS leave out zeros in their readings.

 

Can someone clear this up for me? Thanks

[Guest GuyMcBeerdrinker]

Hooooly Schnikees..

I think I found the answer. I guess I wasn't paying close attention to the type of coordinate formats.

 

Can someone recomend a good Orienteering or Lat. Long. Book? I know there are probably tons of sites out there with info, but I kinda like books because you can always reference back to them, and you can take them along with you on a hike.

[Guest Moun10Bike]

quote:

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Originally posted by GuyMcBeerdrinker:

Can someone recomend a good Orienteering or Lat. Long. Book?

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Hi Guy,

 

Check out my response in the "Coordinate help with Legend" topic.

[Guest cache_only]

You have the LAT and LON flip-flopped.

 

Parallels of Latitude run east-west but are measured in degrees north-south. The Equator is N 0 degrees LAT and the North Pole is N 90 degrees LAT. Remember the popular 38th Parallel from the Korean War? This meant exactly N 38 degrees LAT. The Equator can also be referred to as S 0 degrees LAT, and the South Pole becomes S 90 degrees LAT.

 

Meridians of Longitude run north-south but are measured in degrees east-west. The Prime Meridian, E or W 0 LON, runs through Greenwich, England (pronounced GREN-itch, not "green" as in the color, and not "witch" as in Haloween). All world time zones, and the military's Zulu time, are all based on this time known as Greenwich Mean Time. It is accepted as a standard time identifier. There are 360 degrees of Longitude, but they are measured to a maximum 180 East and 180 West. By the way, E 180 LON and W 180 LON is the same Meridian of Longitude, and it is exactly opposite the Prime Meridian on the globe.

 

As far as all these negative numbers go, it is a miscarriage of science and navigation. I am thoroughly irate with this method of coordinate identification. There is no such thing. If you crossed the Equator going from the Northern Hemisphere into the Southern Hemisphere, the darned GPS should switch to S instead of N, not just change to a negative sign in front of the number. Same with crossing the Prime Meridian, the letter W should switch to E, not go to negative numbers. Think about it, if the engineers can program the GPS to go to negative numbers, why couldn't they program it to switch letters?????????

 

So many people get confused with these negative numbers and I can't blame them. It's ridiculous, junk science/navigation.

 

Hope this helps,

Rob

[Guest Moun10Bike]

quote:

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Originally posted by cache_only:

So many people get confused with these negative numbers and I can't blame them. It's ridiculous, junk science/navigation.

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Actually, it is good science -- mathematics. It is using the familiar coordinate axis, with longitude along the X-axis and latitude along the Y-axis. The origin marks the intersection of the equator and the Prime Meridian. Coordinates plotted in the lower left quadrant have negative X-axis values and negative Y-axis values, coordinates plotted in the upper right quadrant have positive X-axis values and positive Y-axis values, etc.

[Guest cache_only]

Yes. I am familiar with this system. It is called the Cartesian Coordinate System, named after its inventor, French mathematician Rene Descartes.

 

But this isn't mathematics. Navigation is a discipline of geography. There are *only* four prefixes: N;S;E;W. All numbers are expressed in positive values.

 

Rob

[Guest Mike_Teague]

GPS _IS_ mathmatics, from the orbits of the satellites, to the position solution, you name it.... If you look at the NMEA output from the GPS, it displays +/- also..

 

Anyhow, it is _very_ easy to remember, anyone confused by it just needs to learn it once..

 

 

[This message has been edited by Mike_Teague (edited 05 May 2001).]

[Guest Moun10Bike]

quote:

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Originally posted by cache_only:

But this isn't mathematics. Navigation is a discipline of geography. There are *only* four prefixes: N;S;E;W. All numbers are expressed in positive values.

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Mathematics is the root science behind just about every scientific discipline. In this case, mathematics are applied for a variety of calculations in navigation, such as distance between points, angles between points, etc. For example, if you need to figure the distance between two points when you know only their lat/long coordinates, you plug the values into the formula d = 2*asin(sqrt((sin((lat1-lat2)/2))^2 + cos(lat1)*cos(lat2)*(sin((lon1-lon2)/2))^2)) (note that this assumes a perfect sphere for the earth's surface). If you use positive values for all directions N, S, E and W, formulas such as this don't work. That's why the coordinate system is used and points south of the equator or west of the Prime Meridian are assigned negative values.

[Guest Moun10Bike]

n't they program it to switch letters?????????

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Actually, my GPS does this. The +/- only appears when the data is exported.

[Guest cache_only]

You guys aren't following the context of my position (no pun intended):

 

Sure, coordinates shown on a GPS are derived from trigonometric calculations. That's where the math ends. The coordinates themselves DO NOT exist with negative numbers. You're trying to have mathematical principles cross over into a geographic principles. It doesn't work. There is already a rule in place, that I described earlier, that has worked for years and doesn't need to be "new and improved" like some kind of laundry soap.

 

You have to keep in mind that the Cartesian plane is a *theoretical* plane. Using negative numbers is totally permissible in calculations, but expressing a spot on the earth using negative coordinates is crazy. Describing direction in negative terms is illogical and ridiculous.

 

Can you imagine a gas station attendant telling a lost motorist to "just go -90 degrees horizontally, sir." WTF???? I would prefer to hear, "just go west, sir."

 

Wouldn't the former sound ridiculous? And this is not a strawman argument. It is applicable to your proposal.

 

No hard feelings. We're just having a good, spirited, academic debate. That's healthy.

 

Rob

[Guest Moun10Bike]

quote:

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No hard feelings. We're just having a good, spirited, academic debate. That's healthy.

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Absolutely! Besides, we're discussing one of our favorite topics!

 

But, I still disagree!

[Guest Moun10Bike]

quote:

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No hard feelings. We're just having a good, spirited, academic debate. That's healthy.

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Absolutely! Besides, we're discussing one of our favorite topics!

 

But, I still disagree!

[Guest cache_only]

Moun10bike:

 

How do you get quotes to appear in bold text and isolated between the two lines? I cannot seem to figure it out. A little help, please?

 

Thanks,

Rob

 

[This message has been edited by cache_only (edited 07 May 2001).]

[Guest Moun10Bike]

quote:

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Originally posted by cache_only:

How do you get quotes to appear in bold text and isolated between the two lines? I cannot seem to figure it out. A little help, please?

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If you click the icon farthest to the right of the purple date and time stamp on the post you want to quote, the entire contents of that post will get placed between the tags that you want. Then you can just edit what you want to appear in your reply. You can also place the tags manually. The tag used to mark the start of indented text is (QUOTE), although you need to replace the parentheses with brackets (I can't type it that way or it will think I'm starting a quote!). To mark text as bold, use (. To end a quote section, type (/QUOTE) after the text you want to appear indented, and similarly use (/:rolleyes: to end the bolding of text.

 

There are other tags you can use, too: (U) and (/U) for underline, (I) and (/I) for italics, etc. It seems to mimic HTML patterns.

[Guest Silver]

Anytime you post a message, there is a link on the left-hand side of the textbox that opens a new window showing all of the UBB codes, with examples. The help page is located here.

 

Hope it helps.

 

Silver

[Guest Silver]

Anytime you post a message, there is a link on the left-hand side of the textbox that opens a new window showing all of the UBB codes, with examples. The help page is located here.

 

Hope it helps.

 

Silver

[Guest Moun10Bike]

A-HA! I knew there had to be a link to some info on the UBB codes around! Thanks, Silver!

[Guest ericdb1]

I have question that I hope one of you can assist me with. My wife and I are new to this activity and having a great time.

We have found four caches so far and so far the coordinates have been close. However the last couple we had to use hints because the coordinates listed were anywhere from 70 to 150 feet off. Now if I were in an open field this would be no problem, but in the woods I am learning that this can prove frustrating.

I have found some good info in another topic on how to shoot azmiths N/S and E/W based on lat long readings my GPS gives me to determine cache location. This worked well for the two caches that were at their printed coordinates. The other two however were a good ways off. Anyway here is my question. If I am reading N33*26.529 W084*40.621 and I am looking for N33*26.551 W084*40.578, is there a way for me to determine the distance I should be from the cache? Sorry that I wrote so much information here. Appreciate the help.

[Guest ericdb1]

I have question that I hope one of you can assist me with. My wife and I are new to this activity and having a great time.

We have found four caches so far and so far the coordinates have been close. However the last couple we had to use hints because the coordinates listed were anywhere from 70 to 150 feet off. Now if I were in an open field this would be no problem, but in the woods I am learning that this can prove frustrating.

I have found some good info in another topic on how to shoot azmiths N/S and E/W based on lat long readings my GPS gives me to determine cache location. This worked well for the two caches that were at their printed coordinates. The other two however were a good ways off. Anyway here is my question. If I am reading N33*26.529 W084*40.621 and I am looking for N33*26.551 W084*40.578, is there a way for me to determine the distance I should be from the cache? Sorry that I wrote so much information here. Appreciate the help.

[Guest lostsoul]

desired LON. At this point you should be right on the specified coordinates of the cache. In this method you are moving a strict N-S and then a strict E-W, thereby isolating one variable at a time. It is much easier this way.

 

Also, a compass is valuable in the event your GPS fails while on the hunt. When I dismount my vehicle to begin my search, I always walk a few paces to get an initial track and bearing. I write the *bearing* to the cache on a piece of paper. If my GPS fails for any reason on the hunt, I refer to the bearing from my truck to the cache and add (or subtract, it doesn't matter) 180 degrees to get a back azimuth to my truck. Follow this back azimuth and it should lead you to your vehicle (or place of origin, whatever the case may be).

 

If you do not have a compass (or even if you do), *ALWAYS REMEMBER TO MARK (STORE) THE LOCATION OF YOUR VEHICLE WHEN BEGINNING THE SEARCH.* Do not rely on that awkward, awful , MOB (Man Overboard, or, "breadcrumb") feature. The EXACT path you took to the cache isn't important, but the location of your vehicle is! I've gotten turned around a few times (forgetting my compass at home), and it gets downright scary when it starts getting to be dusk and you find you lost your orientation to your vehicle. If you stored your vehicle location into the GPS, then just hit the "GO TO" feature to take you back to your vehicle. The MOB feature is difficult to use and unreliable. I programmed mine to mark every minute, and one time I tried to use it only to find out it saved two points: one a mile from me and another 22 miles from me. I was in trouble. REMEMBER TO STORE THE LOCATION OF YOUR VEHICLE!

 

If you want a real good compass, get one from a maker called Stocker & Yale. They are located in Beverly, Massachusetts. They make the compasses for the military and they are available to civilian sales. I have the one with the radioactive tritium for use at night. It is self-illuminating. You do NOT need to shine a flashlight on it to get it to glow at night (as with phosphorous types of illumination). It is about $100. The non-radioactive (non-glowing) one costs about $80. They are well worth the money.

 

Hope these tips help. Good luck and take care. Rob. "

 

Then there is the other info which I've got from this forum and that is that 1 second of your coordinates (remember they are in decimals in the formats we are using) corresponds with approx 102 feet.(depending on your lat/lon postion) Somebody on this forum may explain it much better than I do. I'm a newbie too.

 

[This message has been edited by lostsoul (edited 09 May 2001).]

[Guest cache_only]

quote:

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Originally posted by Moun10Bike:

There are other tags you can use, too: (U) and (/U) for underline, (I) and (/I) for italics, etc. It seems to mimic HTML patterns.

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Thank you very much, Moun10bike. Your help is greatly appreciated. (manual tag on *greatly*. Not bad, huh?) Thanks again. I owe you one.

 

Now, Silver: What in the world are UBB codes?

 

Thanks,

Rob

[Guest cache_only]

quote:

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Originally posted by ericdb1:

If I am reading N33*26.529 W084*40.621 and I am looking for N33*26.551 W084*40.578, is there a way for me to determine the distance I should be from the cache?

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Yes. Have you entered the cache as a waypoint? If you are in the "Go To" feature the distance should appear on the screen.

 

There is another way to determine the distance between two random coordinates. I have a Garmin 12. No matter what make you have, there should be something similar. Here's how:

 

1. Create a waypoint for N33*26.529 W084*40.621

 

2. Create a waypoint for N33*26.551 W084*40.578

 

3. On the menu page, there is something named "Dist and Sun" (for distance and sunrise/sunset info). Go into this feature.

 

4. For "from," enter the waypoint of your position, listed above, by scrolling with the arrow key, spelling out the waypoint name.

 

5. For "to," repeat the procedure using the waypoint name you gave to the cache.

 

When you press the final enter button on the "to" waypoint, the distance between the two, and sun info will appear. It's very handy. I use it often.

 

I just did it using your two waypoints. Your cache was at a bearing of 62 degress from your position and at a distance of .05 miles (*roughly* 264 feet). By the way, the sun, at the cache you mentioned, rose today at 06:42:36 and will set at 20:27:37.

 

These GPS units are phenomenal!

 

Rob

 

[This message has been edited by cache_only (edited 10 May 2001).]

 

[This message has been edited by cache_only (edited 10 May 2001).]

[Guest ericdb1]

I did find the feature that you spoke of Rob. Thanks for the info. My 320 would only show .01 for the closest dist to the cache, until today. I read on the forums about a firmware update for the 320 and applied it today. Now my dist reads in FT as I get below .01. The sunrise feature is also very cool. You're correct these toys are sure fun!

[Guest cache_only]

quote:

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Originally posted by ericdb1:

My 320 would only show .01 for the closest dist to the cache, until today. I read on the forums about a firmware update for the 320 and applied it today. Now my dist reads in FT as I get below .01.

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Be careful with this. It is not uncommon to have position error of anywhere up to 50 or 60 ft if you are working from 3 or 4 satellites, all with marginal signals. What good might "3 ft to go" do under these circumstances?

 

I'm not trying to rain on your parade, but don't put too much stock into the ft display. It is only as good as the number of acquired satellites and their respective signals.

 

Rob

[Guest Silver]

s a horizontal ruler, shows the quote, another horizontal ruler, etc.

 

They are simple codes that anyone can use and the brakets make it easy for the BBS program to parce the input.

 

These types of features, I'm sure, are what made Jeremy chose UBB to host the forums on. It's a very nice system.

 

Silver

[Guest cache_only]

quote:

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Originally posted by Silver:

If you look at the end of almost any forum page you will see the forums are run by Ultimate Bulletin Board Version 5.47e...

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OK. I see. I tried to learn how to construct a web page a couple of years ago, so the bracketed commands look a little familiar. I guess UBB is similar to Netscape's Composer web-page design software: a little more user-friendly than straight HTML.

 

Thank you for the help. There is so much I want to learn and so little time.

 

Thanks again, Silver.

 

 

[This message has been edited by cache_only (edited 11 May 2001).]

[Guest welshie]

Just like to point out that Greenwich is not the origin for both latitude and longitude.

 

N51:28:37 E0:00:00 WGS84 is the approximate co-ordinates of the original Royal Greenwich Observatory, where the prime meridian was established.

 

The "origin" of latitude and longitude is somewhere off the western coast of Africa.

 

http://pubweb.parc.xerox.com/map/ht=11.52/wd=23.04

[Guest cache_only]

quote:

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Originally posted by welshie:

Just like to point out that Greenwich is not the origin for both latitude and longitude.

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I claimed Greenwich is the origin in terms of longitude only. For me to claim it is the origin in terms of latitude would mean that I believe a portion of England rests on the Equator.

 

I realize England is well north of the Equator.

 

We yanks is dumb, but puullllleeeeeeeease...!

 

All in good fun. By the way, I am a devotee of "Are You Being Served?" It's a huge hit on public television here in the states. It has achieved cult status. I hear it still isn't so hot in its native England. Is this true? Are the cast members still involved in television over there?

 

Take care,

Rob

 

[This message has been edited by cache_only (edited 20 May 2001).]

[Guest Nemesis]

quote:

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Originally posted by cache_only:

...By the way, I am a devotee of "Are You Being Served?" It's a huge hit on public television here in the states. It has achieved cult status. I hear it still isn't so hot in its native England. Is this true? Are the cast members still involved in television over there?...

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Well, that's a blast from the past! Are you Being Served was made in the mid '70s (I think), we have had repeats here in New Zealand up until a few years ago.

 

I'm glad to see you Yanks are beginning to appreciate the finer points of British (toilet (or bathroom if you like )) humor.

 

As far as I know, most of the older members of the cast are dead. The guy who plays Mr Humpheries (I have forgotten his name) occasionally gets small (camp) parts on TV specials etc.

 

Cheers,

Donovan Govan.

[Guest Nemesis]

quote:

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Originally posted by cache_only:

...By the way, I am a devotee of "Are You Being Served?" It's a huge hit on public television here in the states. It has achieved cult status. I hear it still isn't so hot in its native England. Is this true? Are the cast members still involved in television over there?...

---

 

Well, that's a blast from the past! Are you Being Served was made in the mid '70s (I think), we have had repeats here in New Zealand up until a few years ago.

 

I'm glad to see you Yanks are beginning to appreciate the finer points of British (toilet (or bathroom if you like )) humor.

 

As far as I know, most of the older members of the cast are dead. The guy who plays Mr Humpheries (I have forgotten his name) occasionally gets small (camp) parts on TV specials etc.

 

Cheers,

Donovan Govan.

[Guest Monz]

No one watches "are you being served" here anymore... everyone is glued to this new action serial called "Starsky & Hutch"

 

j/k

 

Besides... for the finer points you need to watch "Fawlty Towers"

 

[This message has been edited by Monz (edited 21 May 2001).]

[Guest Monz]

No one watches "are you being served" here anymore... everyone is glued to this new action serial called "Starsky & Hutch"

 

j/k

 

Besides... for the finer points you need to watch "Fawlty Towers"

 

[This message has been edited by Monz (edited 21 May 2001).]

[Guest cache_only]

Donovan and Monz:

 

Thanks for the updates.

 

I remember watching Starsky and Hutch as a young fella in the '70s. It was in the same genre as Dukes of Hazzard and CHIPs. A lot of people bought Ford Gran Torinos and emblazoned them with that crazy white stripe in homage to the one in the show.

 

Following Are You Being Served? here in Detroit is Keeping Up Appearances. I watch that often, but not with the same devotion or enthusiasm as AYBS? (I am so hot for Hyacinth's sister, Rose. Grrrrrrrrr). There is also another British show about a black chef. That runs a few nights a week, but it is lame and not funny in the slightest. I remember watching Benny Hill *every* night when it ran here in the early '80s. It ran for about 5 years and I was addicted to that as well.

 

Thanks for rekindling all my very fond memories of British comedy. It is much, much better than the brainless, empty, not-in-the-least-bit-funny American comedies (except for shows like Seinfeld and Frasier).

 

Thanks for the recommendation of Fawlty Towers. I'll be sure to catch it if it ever gets aired here.

 

Take care, my friends.

Rob

 

[This message has been edited by cache_only (edited 21 May 2001).]

[Guest Anton]

Confussion?

 

Like when you get hit in the head with the GPS your wife threw out the car window, but it came back and hit you in the head? That not only hurts, it can make you pretty upset and confused!

 

Anton

[Guest Nemesis]

yne, it's really dire .

 

Cheers,

Donovan Govan.

[Guest Monz]

Never heard of the rip off one...

They only made 12 episodes of the original Fawlty Towers and ever one of them is a classic if you want a real belly laugh let me know and I will buy the videos for you and send them out... they always cheer me up.

[Guest Nemesis]

quote:

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Originally posted by Monz:

Never heard of the rip off one...

 

I envy you!

 

They only made 12 episodes of the original Fawlty Towers and ever[y] one of them is a classic if you want a real belly laugh...

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I agree, the original Fawlty Towers is great, it's well worth watching.

 

Cheers,

Donovan Govan.