Differences between revisions 2 and 3
Deletions are marked like this. Additions are marked like this.
Line 2: Line 2:

Before going out on your first benchmark hunting trip, be sure to educate yourself on these basic topics: ["designation"], ["PID"], ["azimuth"], ["witness post"], [:to reach:to-reach], ["azimuth mark"], ["reference mark"]. Also look through the list of [:Equipment:benchmark hunting equipment] to get an idea of what to take along.
Line 5: Line 7:
 * Highlight whether the '''horizontal position''' of the PID is ["adjusted"] or ["scaled"]. On an ["NGS"] datasheet, find the horizontal (latitude and longitude) coordinates. They will probably be around the 9th of the lines that start with the PID. After the coordinates will be a word in capital letters - either ADJUSTED or SCALED. On a geocaching datasheet, 2 lines under the coordinates will be the words "location is". After those words, the datasheet will say either ADJUSTED or SCALED. If the mark is horizontally adjusted, its location will be much more accurate than you can measure with your ["GPS"] receiver. If the mark is horizontally scaled, its location will be off by as much as several hundred feet, but is usually within a hundred feet. For horizontally '''scaled''' marks, you can use your GPS receiver to find out about where to park your car. After that, you must rely on the to-reach instructions. Even for horizontally '''adjusted''' marks, the to-reach information often provides better accuracy than your GPS receiver.  * Highlight whether the '''horizontal position''' of the PID is ["adjusted"] or ["scaled"]. On an ["NGS"] datasheet, find the horizontal (latitude and longitude) coordinates. They will probably be around the 9th of the lines that start with the PID. After the coordinates will be a word in capital letters - either ADJUSTED or SCALED. On a geocaching datasheet, 2 lines under the coordinates will be the words "location is". After those words, the datasheet will say either ADJUSTED or SCALED. If the mark is horizontally adjusted, its location will be much more accurate than you can measure with your ["GPS"] receiver. If the mark is horizontally scaled, its location will be off by as much as several hundred feet, but is usually within a hundred feet. For horizontally '''scaled''' marks, you can use your GPS receiver to find out about where to park your car. After that, you must rely on the to-reach instructions. Even for horizontally '''adjusted''' marks, the to-reach information often provides better accuracy than your GPS receiver.  (Note: very rarely, a mark will say HD_HELD1 or HD_HELD2 instead of ADJUSTED or SCALED, but for benchmark hunting purposes, you can consider these the same as if it said ADJUSTED.)

You've probably already found one or two benchmarks while doing something else. Now you want to go on your first benchmark hunting trip. Pick about 10 ["PID"]s to look for, preferably fairly close to each other. If you can, pick some that other people have found within the last year or so. This should assure you of a good experience finding benchmarks and prevent you from going home without a find on your first trip.

Before going out on your first benchmark hunting trip, be sure to educate yourself on these basic topics: ["designation"], ["PID"], ["azimuth"], ["witness post"], [:to reach:to-reach], ["azimuth mark"], ["reference mark"]. Also look through the list of [:Equipment:benchmark hunting equipment] to get an idea of what to take along.

Print out every page of PIDs' ["datasheet"]s. Even if you intend to 'go paperless' with your benchmark hunting, it is good to use paper at least on your first trip. On each paper, use a highlighter or other marking method to highlight these things:

  • Highlight whether the horizontal position of the PID is ["adjusted"] or ["scaled"]. On an ["NGS"] datasheet, find the horizontal (latitude and longitude) coordinates. They will probably be around the 9th of the lines that start with the PID. After the coordinates will be a word in capital letters - either ADJUSTED or SCALED. On a geocaching datasheet, 2 lines under the coordinates will be the words "location is". After those words, the datasheet will say either ADJUSTED or SCALED. If the mark is horizontally adjusted, its location will be much more accurate than you can measure with your ["GPS"] receiver. If the mark is horizontally scaled, its location will be off by as much as several hundred feet, but is usually within a hundred feet. For horizontally scaled marks, you can use your GPS receiver to find out about where to park your car. After that, you must rely on the to-reach instructions. Even for horizontally adjusted marks, the to-reach information often provides better accuracy than your GPS receiver. (Note: very rarely, a mark will say HD_HELD1 or HD_HELD2 instead of ADJUSTED or SCALED, but for benchmark hunting purposes, you can consider these the same as if it said ADJUSTED.)

  • The ["designation"] of the mark. On an NGS datasheet, on about the second line and after the word DESIGNATION, will appear the designation, the official name of the mark. On a geocaching datasheet, the designation line is the 4th line under the coordinates. In case the type of the mark is a disk, you must find a disk with this designation. Finding a disk with a different designation is not a find, even it is in the exact same spot as what you're looking for. If the designation on the datasheet does not have the word RESET, but the mark you find does have that word, then it is not a find - the mark you're looking for may be gone and replaced by a RESET mark that didn't make it into the NGS database. If what you find says RM1, or RM2, etc., then it is a ["reference mark"], not what you're looking for, and does not count as a find.

  • The most recent to-reach measurements. Each PID has a section called the recovery section, where each finding report for the PID will have a date. For this highlighting exercise, read these recoveries from newest to oldest. Find the most recent one that has distances measured to local reference points. The last distance mentioned is the closest to the mark and is therefore the most important (assuming it still exists). When hunting, you will probably want to look for this last-mentioned reference point first.

These are the most important items in a datasheet. Just before going to each PID's location, review these highlighted items in its datasheet. Making a drawing of what you understand from the geometries of the to-reach statements can sometimes save you a lot of time and false starts.

Be ready to take notes. A very important aspect of mark ["recovery"] is to note any changes since the last recovery report and inform the NGS of these changes in your recovery report.

FirstTime (last edited 2009-03-21 21:03:18 by localhost)