This link shows a woman petting a bison in Yellowstone National Park.
Not really the smartest thing to do.
The Fox News station reports that Bison can be incredibly dangerous. This is true with just about all the large mammals in the park.
Wednesday, April 27, 2016
Many things can affect the operation of a compass.
Keep ferrous objects away from the compass body.
I went to the U.S. Army's manual on Map Reading and Land Navigation verify this issue.
The manual stated:
"Metal objects and electrical sources can affect the performance of a compass. However, nonmagnetic metals and alloys do not affect compasses readings. The following separations distances are suggested to ensure proper functions of a compass:
High-tension power lines .........................................55 meters
Field gun, truck or tank.............................................18 meters
Telegraph or telephone wires and barbed wires .....10 meters
Rifle ..........................................................................1/2 meter"
I would offer that a compass should be protected from some electronic/electric equipment such as flash lights and GPS receivers.
Frequently in my backcountry land navigation class, I am asked about the need to carry a back-up compass. Generally students are interested in a light weight model that is low in cost, small in size, and would “fill in” as needed.
I purposefully evaluated several models many consider to be back-up options. When choosing a back-up magnetic compass, the hiker must ask himself “What are my priorities? Is it accuracy? Reliability? Cost? Size and weight?”
Different models bring different values to the outdoorsman. If the primary compass got crushed, misplaced, or stopped working what model would serve as a back-up to get out of the woods safely? Generally a back-up compass isn’t as capable as the primary. People want to cut back on weight and expense.
For this evaluation, I selected five commonly used compass models. They are: the Brunton 9020G, a wrist watch compass “The Navigator” (sold by Country Comm), the Silva Type 3, the Silva Type 7, and a ball compass by Outdoor Product (not Outdoor Research.)
I will compare the five selected back-up units to the highly regarded Silva Ranger (CL 515) and Brunton 8010G base plate compasses to establish a bearing standard. The Silva ranger and 8010G models are oriented to magnetic north as shown below:
Figure 1 The Silva Ranger (left) and the Brunton 8010G (right.)
Neither the Silva Ranger nor Brunton 8010G are adjusted for declination for this review. This provides a consistent baseline for evaluation purposes.
To begin the comparison of the back-up compass models, I chose to define them in the categories of (1) reliability (2) accuracy and readability (3) cost and (4) size and weight.
I picked up each back-up compass model option and turned it in place rotating the compass and magnetic needle. I then stopped and set it on a flat surface oriented to magnetic north. I quickly found that the Brunton 9020G, and the Silva type 3 and 7 settled quickly and matched the bearing of the standards. The compass needles quickly aligned to magnetic north and required little movement on my part to stabilize the compass.
The ball and wristwatch compasses were extremely finicky. Both models required time and manipulation (moving the compass housing side to side, up and down) to get them to align to magnetic north. Both required what I consider to be excessive movement to level the housing to allow the needle or ball to swing freely. This was especially true of the ball compass; frustrating.
Figure 2 Compasses from left to right: The Brunton 9010G, The Navigator, Outdoor Product ball compass, Silva type 7 and type 3. Note that the five compasses close proximity to each other cause the magnetic needles pointing in different directions.
Accuracy and readability:
I then checked the compasses for their alignment to magnetic north. All models were in general agreement but the three baseplate compasses ( Brunton 9020G, Silva Type 3, Silva Type 7) allowed for a more accurate reading with 2° increments marked on the rotating dial. Further, each baseplate compass could be used for sighting on a distant object to triangulate the hiker’s position.
The ball compass and the watch compass did not provide for accurate measurement; they just aren't built for that. The Navigator has increment tick marks every 10° and the ball compass is marked every 15°. That said, both will provide a trend of direction. Knowingly choosing a trend of direction verses specific bearing accuracy is a critical choice for the outdoorsman when selecting a back-up compass model. The impact of providing a trend of direction is that these compasses will indicate that the hiker is moving in a generally northerly direction as opposed to hiking along a bearing of 350°.
The most affordable are the ball compass ($2.00) and the Navigator (under $5.00). The three baseplate models range from $10 to $12.
Size and Weight:
The wrist watch Navigator is the most compact and is read quickly. Having a compass on the wrist takes a bit getting used to; it’s just different. The ball compass is most frequently worn on the exterior of a jacket or on a pack’s web gear. Both are quickly accessible and are feather light.
The Brunton 9020G is the largest of the group. That said, all three baseplate compasses fit easily in a shirt pocket.
Size and weight is of minimal concern for all five models.
The ball compass and Navigator are fine for short day hikes. Both are good choices as an introductory model and get young people interested in navigation early.
For serious backcountry adventures I’d opt for one of the baseplate models. The 9020G ability to adjust for declination is a big plus for me. The baseplate models are the natural progression for learning the finer points of compass navigation.
Sunday, April 3, 2016
When looking at a US Geologic Survey (USGS) map the hiker will find benchmark symbols sprinkled across the topo. Benchmark and the many other symbols provide the details of a map. Symbols represent features such as mines, bridges, dams and many more items. To see a complete look at symbols visit the USGS site for more information.
Figure 1 Symbol examples from the USGS Topo Map Symbols web page.
Figure 2 Benchmarks on a topographic map.
A benchmark is control point on the map. Control points are positions of accurate measurement in terms of elevation and position (latitude and longitude.) Benchmarks are also known informally as “survey markers.” Originally, these markers were used in land surveying and by civil engineers for construction purposes. Benchmarks help to accurately determine location.
From www.mytopo.com’s frequently asked questions:
“A benchmark, abbreviated "BM," is a location whose elevation and horizontal position has been surveyed as accurately as possible. Benchmarks are designed for use as reference points, and are usually marked by small brass plates.”
Occasionally a hiker will find a benchmark plate in the backcountry. The image below is an example of the brass plate. These plates should not be tampered with and are not souvenirs to be taken home.
Figure 3 Brass benchmark found in the backcountry.
Note the elevation data found in the center of the plate. Importantly, elevation is measured in feet above sea level and not in relation to the adjacent topography. Wikipedia.com reports that over 740,000 benchmarks are dispersed around the United States.
Though elevation data is provided on the map, coordinate information (e.g., latitude and longitude, UTM) is not. It’s is up to the hiker to interpolate and determine the information through the use of a map tool.
Remember that the coordinate data provided on a topographic map is in degrees, minutes and seconds (GPS menu settings format: dd mm ss.s) while a new GPS is set at the factory to degrees minutes.minutes (GPS menu settings format: dd mm.m.)
Finding a benchmark can confirm your position on the map.
To improve you GPS skill level try “Benchmarking,” an activity similar to geocaching. The objective is to find the brass plates in the field. For more information visit Geocach.