Offset Geocaches and how to do them

 Sep 15, 2019

This week we are discussing Offset Geocaches

An "OFFSET" or Projection Geocache is where you:

1) go to the posted coordinates on the cache page,

2) get some information either from something at the coordinates

or from information on the cache page,

3) do some MATH {OH NO!, not THAT!!!} and then,

4) determine your next place to search.

Ideally, this "next place to search" would mean going to the new

coordinates and looking for the cache container but...

it could be a multi-staged geocache meaning, you  you start over at step 2 above

and continue until you reach the place where the container is!

Is an offset cache a multi or a puzzle????

There is quite a lot of discussion on this topic.

Here are some exerts from the Geocaching Forums

Offset caches are a variation on multi-caches. They are listed as a multi-cache

when selecting a cache type. They are not found by simply going to some

coordinates and finding a cache there. With the offset cache the published

coordinates could be of an existing historical monument, plaque, or even a

benchmark that you would like to have your cache hunter visit. At this spot,

the hunter looks for numbers or information already appearing on the marker

or on some part of the marker or site (geocachers NEVER deface public or

private property). The geocacher is then able to manipulate these numbers

using instructions posted on the cache page to continue the hunt.

For instance, the official designation of "multi" is actually "multi-cache." In

an offset, there is only one cache with multiple stages. Virt cache stages aside,

if there are multiple stops it's considered a multi. Where's the caches?

Further, if you have an offset where your don't have to visit the anchor coords

it is a puzzle, if you do it's a multi. What if visiting the anchor is optional,

say to get a hint is you're having problems solving the puzzle?

In my humble opinion, if there is such a thing...

If you have to visit the coordinates on the cache page, find some

information there, then do some MATH (Oh No Again!), then go

find the container - it is a Multi - even if there is more than one place to

get information.

Am I correct - I think so!

Now the MATH portion of the geocache!!!

To do an Offset or projection, you need 3 things

1) your starting point - lucky for us - it is usually right where you are!  I have seen

and actually own a couple of geocaches where you go to the coordinates on the page

and then search for something (in my cases, usually a particular sign) and then that

point is your actual starting point.

2) A direction - this is sometimes called a bearing.  Bearings are usually expressed

in degrees but I have seen more than one cache that listed the bearing in an odd

unit of measurement which we then had to convert to degrees.  Just like a circle,

a compass has 360 degrees with 0 degrees being North, 90 degrees East, 180 degrees

South and 270 degrees is West.

3) The last item you need is a distance - or how far you are to travel

in the particular direction you were given in #2 above.  Now some cache

owners make it easy on you and simple tell you to go XX number of feet East.  Then again

you could be told to go YYYYYYYY number of inches West.  Make sure you convert

those inches, feet, centimeters, etc to the correct type before doing your calculations!

No! - you do not need the paper and pencil - APPs are our friend!!!

There are numerous ways of calculating the bearing and distance but

here are 2 easy ways that I know of.  I repeat - there ARE other ways of doing this!

using the c:geo app

from the main menu, look for "Go To"

At the top is Coordinates.  You can either enter your own coords OR

press "My Coordinates" and your current coords will be entered

Below that is "From the position"

Enter the Bearing in DEGREES

Enter the Distance

you have several choices for distance (meters, kilometers, feet, yards, or miles)

Then press the Compass symbol (4th from right at top)

follow the compass all the way to GZ!!!

using my Garmin eTrex Touch

from the main menu, look for and press "Sight 'N Go"

A compass pops up.  Rotate until the correct bearing

is obtained and press LOCK DIRECTION.

Press Project Waypoint.  Select your distance units (Miles, Yards,

Feet, Kilometers, Meters or Nautical Miles) then enter the amount.

Click on the checkmark - press save and your compass will come up!!!

follow the compass all the way to GZ!!!

As I said above - there are numerous tools and

apps out there to do your projection.

You can try the steps above or find another app you like

and search for how to do a projection!!!

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That is all for now

Till next time...

Don't forget to visit our favorite Geocaching Store

Space Coast Geo-Store

Stay Safe & Keep Caching!!!

Suffolk Nana & Papa

 - - - or just plain ol' - - -

SNAP!!! 

#geocaching

#gogeocaching

#SNAPgeocaching

#geocache

On Twitter at: @SNAPgeocaching

On Instagram at: snap_geocaching

The Lonely Cache Challenge Achieved!

Last Updated: July 25, 2024

OK - I understand the first question is probably....

What the heck is a Lonely Cache???

Any cache that you find where the last geocacher

to find that particular geocache was over a year ago.

Simple right - not really!

We thought we had previously met that qualification but could not

1) remember the geocache and,

2) could not find it by reviewing our "Found" database

Well, a review of nearby geocaches revealed there was one

particular geocache about 30 miles away from our home!!!

AND... even though it was a puzzle cache, I knew the final 

coordinates for that particular cache!!!

So all that was left was to travel a small distance, spray down really good

to ward off all the bugs and other creepy crawlies,

and then set off and hope we found the correct trail to the cache

It took us far longer to find the correct trail than we had intended...

but eventually - we found it!!!

The cache in question was GC106A4

More Pieces of Eight

and when we signed the log on June 22, 2019 - it had been

2 years, 10 months and 2 days since the last found log on the cache! 

Now all we have to do is find a Lonely Cache Challenge - 

and then go find it!!!

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We have a lot of fun searching for Challenge caches.

Then you have to see if you qualify to find them!

** Note: Project-gc.com (my favorite Website) has a Challenge checker

in the Tools section of their website where

you can check to see if you qualify

for most challenge caches - they also have a Map of Challenge Caches

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That is all for now

Till next time...

Don't forget to visit our favorite Geocaching Store

Space Coast Geo-Store

Stay Safe & Keep Caching!!!

   

Suffolk Nana & Papa

 - - - or just plain ol' - - -

SNAP!!! 

#geocaching

#gogeocaching

#SNAPgeocaching

#geocache

On Instagram at: snap_geocaching

Why are my coordinates so far off?

Apr 24, 2019

I originally posted this blog back in 

May of 2016.  I recently received some questions

about how to get accurate coordinates.

So I updated the information in this post and...

here is the updated info!!!

Here are some fun facts about

the GPS Satellite Constellation

(the GPS system we use).

The Air Force manages the constellation to ensure the availability of at least 24 GPS satellites, 95% of the time. For the past several years, the Air Force has been flying 31 operational GPS satellites, plus 3-5 decommissioned satellites ("residuals") that can be reactivated if needed.

As of January 9, 2019, there were a a minimum of 24 operational satellites, and allows for up to 32; typically, 31 are operational at any one time, not including the decommissioned, in-orbit spares.

• The United States government currently claims 4 meter accuracy for civilian GPS. Mind you, that's the minimum. Some devices/locations reliably can get 3 meter accuracy.  4 meters is about 12 feet - so the best you can get is about a 24 foot diameter circle.
• The first GPS satellite was launched in 1978.
• A full constellation of 24 satellites was achieved in 1994.
• Each satellite is built to last about 10 years. Replacements are constantly being built and launched into orbit.
• A GPS satellite weighs approximately 2,000 pounds and is about 17 feet across with the solar panels extended.
• Transmitter power is only 50 Watts or less.

Most geocachers have run into either a geocache

whose coordinates are less than desirable.

The worst coordinates for a geocache I ever attempted to find

were more than 2 miles off!!!

Oh, and btw... even with the coords
more than 2 miles off, we got a FTF on that cache!

(via a hint from the CO).

All sorts of things can throw off coordinates including clouds, weather, trees, buildings, and sometimes just the minerals in or on the ground at the ground zero.  We have a LARGE geocache hidden in a giant stack of granite blocks.  We get plenty of DNF logs!  Good luck getting a decent lock there - plenty of bounce.

Another factor in accuracy is time.  Here is an example of GPS accuracy from a handheld GPS (Garmin Oregon). The first image was taken 1 minute after the GPS was switched on , the middle image is after 2 minute and the last image is after 3 minutes. You can see on the GPS screen that more satellites are being received as time goes on (the green bars) and the Location coordinates are slowly changing as the accuracy begins to come down to the final 9 feet. The final Location coordinates are N51°35.203' W4°19.501' which can be considered quite accurate.

So, knowing all this - how do we get more accurate coordinates for a cache.

When placing a cache you need to record the coordinates from the GPS or phone and make sure they are as accurate as possible. This ensures people looking for your cache will have the best possible chance of being close to it. If you don't record the coordinates properly and people look for your cache on a day when accuracy isn't that good they could be many yards or meters (or sometimes miles) from the cache. The following steps will help you get the best coordinates you can.

1. At the cache location, hold your GPS or phone so it has a clear view of the sky – or as clear of any obstructions such as trees or buildings as you can. You can place it down on the ground or on a convenient post or just hold it in your hand. It's recommended you need to leave it like this for at least 10 minutes. If you've just switched it on or it's been in your rucksack or a pocket you may need to leave it a bit longer. This ensures it has a chance to pick up the signal from as many satellites as possible.
2. Check the accuracy figure shown on the screen (see the images for examples). It will slowly decrease as the GPS picks up more satellites but will eventually stop and that indicates the best accuracy you will get at this time. Wait until the accuracy figure has stopped and drops no more
3. Record these coordinates either by writing them down or marking them as a waypoint.  Note: The Geocaching® apps show your current location while navigating to any geocache using the compass feature.  I would also recommend, if using this method, to revisit the same site several times (hours apart) to get multiple readings (see manual waypoint averaging below). 

Waypoint Averaging

Another way of making sure the coordinates are good is to take several different readings at the cache and then average them. To be really accurate you should do this over several days because on any particular day your GPS may not be able to pick up as many satellites as on other days which will affect accuracy. You can average waypoints manually or use the averaging feature of your GPS if it has one (not all of them do but the manual method works with any GPS or phone).

Manual Waypoint Averaging (handheld GPS or phone)

Record the coordinates at the cache location using step 1 to 3 above. Then walk about 30 or 40 feet (10 to 13 meters) away from the cache, turn and then walk back to the cache waiting about a minute at the site before recording the coordinates. Do this a second, third, fourth and even fifth time from different directions. You will find you have a slightly different coordinates each time. You can now 'average' these coordinates to get the best possible ones. This is how it's done.  I recommend waiting hours not minutes between readings as you will be syncing with different satellites.

Let's say your five separate readings are these:

N51° 42.634' W4°19.915'

N51° 42.636' W4°19.917'

N51° 42.637' W4°19.917'

N51° 42.633' W4°19.915'

N51° 42.634' W4°19.919'

Take the last part of the N to give you five numbers like this, 634, 636, 637, 633 and 634. Add them together to give a total of 3174. Divide this by the number of readings (5) to give you 634.8 or rounded up, 635.

Now do the same with the last part of the W which gives you 915, 917, 917, 915, 919. Added together this is 4583. Divide by 5 again to give you 916.6 or rounded up to 917. Your best coordinates are therefore N51° 42.635' W4°19.917'

GPS Averaging Feature (handheld GPS only)

If your GPS has the feature to average waypoints then use that. It will be an option in the menu. From the averaging screen you create a new waypoint and press Start. The GPS will then start recording the coordinates for a period of time. When it's finished you can either use that value or continue the averaging by repeating the process. Please refer to your GPS manual for more details.

Two last Tips:

1.  Keep your GPS calibrated.  This will definitely help with coordinates.

2.  Remember the +/-     If I hide a cache and have +/- 10 feet on my coordinates (a 20' circle) but my GPS is off to the east - then you come along and let's assume you have +/- 10 feet but you are off to the west -  this means we just enlarged that 20' circle to a 40' circle.

Have patience - sometimes it is best to stop looking at your GPS and use what we call "geo-sense".  Look around and ask yourself - Where would you hide it?  Believe it or not - it works quite well.

I compiled this information from numerous sites including Geocaching.com.  Remember, even geocaching.com states your coordinates SHOULD be as accurate as possible.

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 That is all for now

Till next time...

Don't forget to visit our favorite Geocaching Store

Space Coast Geo-Store

Stay Safe & Keep Caching!!!

Suffolk Nana & Papa

 - - - or just plain ol' - - -

SNAP!!! 

#geocaching

#gogeocaching

#SNAPgeocaching

#geocache

On Instagram at: snap_geocaching