Caching Without A Gps

[+Bartster]

There's probably a thread on this already, but couldn't find anything using the quick search.

 

Do many of you geocache using only a compass and map, and calculator of course? I know I've seen some logs where 'cachers found the cache without use of a gpsr.

 

I would like to give it a try, just to step up the challenge a bit. Mostly on multi-cache hunts. The difficulty is in converting the lat-long of each waypoint, to a bearing and distance.

 

Anyone know where I can look up the formula for this conversion? It would need to be something that I could reasonably program into a calculator or PDA.

 

Looking forward to your comments.

 

Cache on dude!

 

Bartster

[+woodsters]

look up WaldenRun. I moved from Massachusetts nearly a year ago and he was up in the thousands of finds and he doesn't use a GPS. What is he up to now?

[+briansnat]

Some do. Walden Run and Web-Ling each have hundreds of finds sans GPS. I've found 2 of mine without one. One because I forgot to bring it and the other to see if I could. I'v also attempted about a dozen others, but eventually had to give in and turn on the GPS.

[+Map Only]

Way to go!

 

I've found about half of mine without GPS, and my buddy "map and compass" is fanatical about not using the little nuisance.

 

I have a rant about people using the gps instead of map skills, but I strictly reserve it for SAR folks in my area - gps is a good tool for some situations, and finding a micro in an urban park is one of them, if you ask me.

 

People have been finding things for a long time without gps. A map, your skills and perhaps a compass and altimeter is always good for knowing your location within 300 feet where I play.

 

Besides, I love machinery of any kind!

[+Map Only]

I haven't changed lat/long to a distance and bearing, except by plotting each on a map. My usual method is to plot the cache coordinates on a map and go there. With geocaching, realize that usgs maps and many others use the NAD 27 datum, which can be scores of feet different that wgs84.

 

I often use the topo map on my computer, which does the plotting for you. The only time I use a GPS for Search and Rescue is while driving. It is just not efficient to navigate by terrain features at 40 mph on logging roads

[+bradandangela.com]

Out of 19 finds, I've found one without a GPS. It required triangulation and I hate math so I just did it all in Microsoft S & T and it got me within 100 feet or so of the cache.

[Mushtang]

The first dozen or so I found were before I owned a GPS, but I was caching with my brother who had one so it's not quite the same.

 

The first cache I found after I bought mine, I didn't even need it. The decription included a photo that was a complete spoiler for me. I lived close by and had seen that view hundreds of times, so I would have been able to find it without a GPS too, but I used it anyway for the practice.

[+Paul G0TLG]

I've done one where the description was so good I was able to do it without a GPS.

 

On another, I forgot to take my GPS to work but did that evening's cache anyway . I plotted the co-ords to a map, walked as close as I could, and used the clue.

[+SamLowrey]

For Christmas I have asked for a few books on Orienteering since I don't know anything about it. Wasn't planning on using it for caching, but why not?

[javaa]

I've done quite a few without a GPS. I usually just use the topozone link on the cache page to plot the location on a larger topo. After that, I use basic map skills, and of course the hint. It generally takes me longer to find the cache this way, but not always. With certain caches it might make it easier because you can see where the obstacles are beforehand. Anyway, its a lot of fun and great map reading practice.

[+Beta Test]

QOC Mike doesnt use a GPS while caching.

[+Bartster]

My usual method is to plot the cache coordinates on a map and go there.

That sounds good, but how do you handle a multi? Do you just do it one leg per trip, and just go back to the computer and print out a new map?

[+The Puzzler]

Anyone know where I can look up the formula for this conversion?

I did my first 30 or so caches without a GPSr. It's a lot more work most of the time, but fun work and well worth doing.

 

Distance in latitude is very simple since one minute of latitude is exactly one knotical mile everywhere on earth. Do the math and that third decimal point of latitude equals almost exactly six feet.

 

Distance in longitude is just a bit trickier because that depends on your latitude.

One minute in longitude is equal to one knotical mile times the cosine of your latitude (1 at the equator, 0 at the poles).

 

1 knotical miles = 1.15 statute miles = 1.85 km

1 statute mile = 5280 feet = 1850 m

 

For instance the cosine of 45°=0.7071 so:

One minute of longitude in Salem Oregon is 1 kn. mi. * 0.7071 = 0.7071 kn. mi.

 

So 0.7071 kn. mi. * 1.15 mi./kn. mi. * 5280 feet/mi. = 4294 feet per minute of longitude in Salem.

 

Have fun.

 

I found that mapquest maps are distorted if you ues them with a ruler. The map grid they use is not corrected for the latitude and thus the map scale (which is displayed horizonatally) is accurate for E/W directions, but not N/S. You need to correct the N/S distance by the cosine of your latitude.

 

Microsoft maps are correctly projected, but they don't print with a scale bar on them (only desplay the scale on the screen).

[+The Puzzler]

That sounds good, but how do you handle a multi? Do you just do it one leg per trip, and just go back to the computer and print out a new map?

Take a map, small ruler and calculator into the field. One of my first caches was a multi I did on my bicycle without a GPSr.

[+Bartster]

Anyone know where I can look up the formula for this conversion?

I did my first 30 or so caches without a GPSr. It's a lot more work most of the time, but fun work and well worth doing.

 

Distance in latitude is very simple since one minute of latitude is exactly one knotical mile everywhere on earth. Do the math and that third decimal point of latitude equals almost exactly six feet.

 

Distance in longitude is just a bit trickier because that depends on your latitude.

One minute in longitude is equal to one knotical mile times the cosine of your latitude (1 at the equator, 0 at the poles).

 

1 knotical miles = 1.15 statute miles = 1.85 km

1 statute mile = 5280 feet = 1850 m

 

For instance the cosine of 45°=0.7071 so:

One minute of longitude in Salem Oregon is 1 kn. mi. * 0.7071 = 0.7071 kn. mi.

 

So 0.7071 kn. mi. * 1.15 mi./kn. mi. * 5280 feet/mi. = 4294 feet per minute of longitude in Salem.

 

Have fun.

 

I found that mapquest maps are distorted if you ues them with a ruler. The map grid they use is not corrected for the latitude and thus the map scale (which is displayed horizonatally) is accurate for E/W directions, but not N/S. You need to correct the N/S distance by the cosine of your latitude.

 

Microsoft maps are correctly projected, but they don't print with a scale bar on them (only desplay the scale on the screen).

Thanks Puzzler. I think that pretty much nails it for me. With that info, and the use of the ole pythagorean theorem ( a squared plus b squared = c squared) I can then figure out the bearing.

 

I have a traditional cache (not a multi) selected for my first find without a gpsr. It's located near a cemetery, so it shouldn't be that difficult.

 

The thought of hunting without a gpsr, with success, excites me. There is a nice little multi located in an urban baseball park, that should be a good exercise for a first multi-cache without a gpsr.

 

After that there are about a half dozen or so caches located 25-30 miles from me, that are hidden in state parks around lakes. These should be a little more challenging, as the obvious landmarks are less frequent when looking at aerial photos.

[+The Puzzler]

A couple more comments from my experience of caching with map and compass.

1) the hint becomes a critical clue in more of the hunts

2) urban areas and open parks are relatively straight forward because you have intersections and other landmarks that are readily visible, and distances from the last know location (an intersections, a turn in a trail etc) are generally fairly short (a few hundreds of meters).

3) Areas without accurate detailed trail maps and where tree cover is enough to eliminate being able to site fixed and known landmarks can be vertually impossible.

 

One of my most frustrating caches ever was one where I walked a trail into the woods some 600-800 meters. The trail was windy and through an environmentally sensitive area with a very complex understory (dozens of hiding places per square meter). The cache description actually gave a false clue, and when I finally found the cache with a gps (quite easily I might add), the cache was probably 50 m from where I had been looking without the aid of a gps.

 

Conversly, on another cache find, in a wooded area, the cache had a beautiful view over a bay and was a nice easy (if steep) 200 m or so from a road. I was able to find the cache more easily than many with a GPSs because I could pace off a fixed N/S distance from the road. I could determine my E/W location withing a couple of meters by sighting very accuratly off the top of a mountain on the other side of the bay.

 

Good luck, and have lots of fun!!

[+Web-ling]

I was an avid orienteer long before I started caching. I found my first 33 caches before I bought my little yellow Etrex. I still do about 70% of my caches GPS-less. I rarely turn it on until I'm pretty thoroughly stuck and unable to locate the cache without it, or if all I have is coords and no access to a printer.

 

The big exception to the GPS-less trend is multicaches. I've only gotten 20/94 multis GPS-less.

 

I've only used a GPS twice for a benchmark, out of 220 found.

 

LostOutdoors.com is my best friend.

[MapheadMike]

Do many of you geocache using only a compass and map, and calculator of course?

 

It's definitely easier to let the major mapping sites plot the points at home than whatever technique is being imagined that would use a calcualtor. I've seen the conversions that some others use elsewhere in the thread and I couldn't begin to imagine trying such things in the field.

 

Edscott is another among the avid orienteers who plays this game without GPS. Ed started a little before me. Most of his geocaching learning curve was on display in the form of old forum posts, both his questions and answers, so I learned a lot by just reading there.

 

I can read a topo map but I knew absolutely less than nothing of the different standards for plotting latitude and longitude (NAD27, WGS84, etc.). It took a while to learn why certain map sites were not plotting the exact spot. Topozone was plotting points in NAD27 for the first few years of geocaching's existence, so most of my early finds were 50 yard grid searches, since that's all the accuracy I had.

 

After learning the reasons for the map problems and adjusting (jeeep.com has a good utility that was useful for a while), I finally found lostoutdoors.com (Ed's posts were the source), which plots points in WGS84 onto topos and aerial photos. Now Topozone and most of the other major mapping sites plot points in WGS84 by default. Lostoutdoors.com is still the best site to use. Their maps and photos can be copied as a single image onto a document, which you can then scale to fit your circumstances. I've used photos blown up as much as 1:1,500 (that make sense with my compass, YMMV).

 

That sounds good, but how do you handle a multi? Do you just do it one leg per trip, and just go back to the computer and print out a new map?

 

What I've done is plot the first stage plus some reference points onto a map of the area. The four reference points would be an the lat/long rounded in each direction to the nearest 1/10th minute. For a first stage latitude of 37° 46.945, I'd plot 37 47.000 and 37 46.900. For a first stage longitude of 77° 32.426, I'd plot 77 32.500 and 77 32.400. Then I'd have the makings of a small grid, in the format that cachers actually use, that I could plot the second stage and subsequent stages with. No conversions from lat/long to UTM and no field math. It works great of you avoid errors in the field (like plotting dd mm.yz instead of dd mm.xyz, that's a confession to some Richmond area friends from last January). If you make a plotting error, or the map that you print doesn't cover the right area, then going back home to print a fresh map is a valid option too.

[+Bartster]

The big exception to the GPS-less trend is multicaches. I've only gotten 20/94 multis GPS-less.

 

. . . .

 

LostOutdoors.com is my best friend.

That's interesting about your multi-finds. Multis obviously pose the biggest challenge to caching without a gpsr.

 

I already knew about LostOutdoors.com from a fellow cacher. Excellent website.

 

Here's another link that you may find handy when looking up plotted points on Mapquest, aerials and topos.

 

It's a very nice clean web page that is easy to use. I've found it very handy.