BACKGROUND

MATERIALS NEEDED FOR PARTICIPATION

• Compass, preferably hand-bearing. Tape measure (50 to 200 feet).
• Probe rod, about 1/4 in diameter, and a minimum of 10 inches long, sharpened to a point. Small shovel and garden trowel (to uncover buried marks).
• Wire brush and rags (to clean dirt off disk).
• Flashlight (to provide illumination in deep holes).
• NOS-USPS Cooperative Charting ID Card . Metal detector (helpful). NGSD geodetic descriptions (from district Cooperative Charting Chair man).
• U.S. Geological Survey (USGS) 7.5' Series (Topographic) maps (helpful, but not essential).
• Copy of the USPS/NOS Cooperative Charting Manual.

TRANSPORTATION

PREPARATION

• Order geodetic descriptions for the geographic area you would like to search. These are ordered from your district chairman (through your squadron chairman) and are specified by county within a given state.
• Collect your computer print out, punch holes in each page and put in a three ring binder for easy reference. Arrange them in the same order you plan to search for them.
• Plot the location of each mark along your search route, if you plan to search in a systematic manner.
• Geodetic marks in cities are easy to locate, even though street names are generally not shown on some maps. If the town or city has an atlas or map, it will facilitate the search.
• Mark station locations with prominent crosses on the map and label each with the station designation for easy access when you are searching.
• With all geodetic marks plotted, it is easy to plan a day's routing for bench mark recovery and to see how to get from one location to another.
• Scale off, with dividers, the distance between each mark and record to the nearest tenth of a mile, though this information may be given in the description text. This will be useful as you drive from mark to mark using the readings on your vehicle's odometer to measure distance.
• Once you have assembled your group of marks (and have them arranged as they occur along your search route) you are ready to take to the field and start the search.
• Plan the timing of your trips to avoid commuter traffic, especially if you're searching along heavily traveled roads. Consideration of seasons also pays off. During the mid year warm months, weed growth (including poison ivy) is at its maximum and can make bench mark access and visibility very difficult. Avoid days when the ground is frozen; you will not be able to dig, even a few inches, into frozen ground to retrieve a bench mark. Trips after a killing frost would be an excellent choice.
• Ensure that no mark is knowingly recovered and reported in a time period less than 5 years.

PROCEDURE

• Start your recovery trip with a full tank of gas and note your odometer reading before leaving home and again when you arrive home.
• Read each description carefully and follow each detail. Use your odometer reading of distance from established local references as given in the descriptions or measured on your route map.
• Locate local references when you reach the station site as outlined in the "to reach" portion of the descriptions. Be sure to read the latest dated descriptions for the location of mark, as they may change drastically from the older description. Use logic and common sense.
• Ask permission if you intend to search on or near private property or dig for a bench mark in someone's lawn. Tell them exactly what you are looking for and where it should be located. Occasionally they will lead you directly to the mark. Clearly state that your are only inspecting for geodetic marks and reporting their condition to update their files. Identify yourself using your NOS-USPS Cooperative Charting Identification Card .
• Establish LOP's from each local reference point using your compass. Measurement of distances will help establish the "fix". Always take accurate compass bearing and distance measurements. The mark should be found at the intersection of your LOP's.
• Search the area in the vicinity of the LOP intercept with a probe to find the exact location using the stated depth as a guide as to how deep to probe. Alternately, a metal detector can be used to locate the mark if it isn't too deeply buried in the ground.
• Look for indentations in the ground or dead grass in the area where you think the mark may be buried. A survey party may have recently dug for it, or left a deep hole where the mark may have been located. At times local surveyors will mark bench mark locations with fluorescent orange paint or fluorescent orange tape on stakes or with the letters "BM" (i.e., bench mark) and an arrow marked with white, orange, or yellow paint on a nearby concrete wall or rock outcroppings.
• In some cases, the mark will be located near a "witness post", i.e., a vertical 3-4 foot post made of metal, plastic, fiberglass, or wood, usually with a white rectangular sign (8" X 11") alerting the observer that a mark is nearby. Newer witness posts (sometimes referred to as 'Carsonite' witness posts) are made of fiber glass and are bright orange with the NOAA logo and a short message. Recognize that many local landmarks may -have disappeared or been altered since the description was written. (Some descriptions were written more than 100 years ago!) Always start the search using the most recent description, generally found as the last entry in the "to find' portion. Consider that occasionally the description was typed incorrectly or a reverse azimuth reading was recorded. A highway, bridge or power line pole may have been moved, widened, relocated or removed. Try to cut a reasonably small plug when uncovering marks in an established lawn. Always refill holes you dig.
• When looking for very old bench marks, such as those located in a post office wall in a small town; remember that the operating post office may have moved 2 or 3 times in the meantime. Postmasters are usually helpful, but it pays to ask the oldest person you see in the area. Asking questions from local residents frequently results in voluntary assistance in the search. Occasionally airport security guards will drive you inside the length of an airfield to help in your search.
• Make notes in the margins of your printed description pages next to each bench mark. Give the date, condition and details of your inspection and description changes.
• Read and check the inscription on the casting and check against the description to be sure the correct mark has been located after it has been found and exposed.

Determine and record the condition of the mark as follows:

• Good...disk is in good condition, easily read, with no signs of having been moved.
• Poor....disk shows evidence of having been moved or is severely damaged mechanically, scuffed, eroded or corroded.
• Not found...the disk cannot be located. Use this category if you find that the description places the mark under a concrete pad, roadway, or in an otherwise inaccessible spot.
• Destroyed...disk is found and is physically removed from the site by you. This disk should be returned to NOS as part of your report. Note in your report that you have recovered and are returning the disk to NOS.

NGS Searchable Database (Nationwide)

Resources for determining your latitude and longitude

Here are some ways to determine your latitude and longitude.

• Use a GPS
• Finding the location of a city in the United States
• Finding the location of a street address
• Finding the location of a non-US city
• Finding the street map of a given lat/lon.
• Other sites or lists of locations

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