Every professional uses some type of tool to help them get through the work day. For some people, this tool is a computer, for others the tool is a hammer or a forklift. For surveyors and engineers, tools such as a surveyor\’s compass and a Jacob staff might come in handy. Here is a quick look at a few tools with multiple uses for a few unique professions.
You might simply think that a compass is just a compass, but there are actually quite a few different styles of compasses. Generally, people are familiar with the small circular tool that we all used on scouting adventures or hiking excursions. Today, people often simply use their smartphone, which usually comes standard with a compass. While a standard compass simply identifies magnetic north in relation to the user, a surveyor\’s compass is a device that also provides information about horizontal angles, which is a much-needed measurement for surveying applications.
We all know what a typical compasses looks like, it\’s simple a round device that is labeled with direction and features a magnetic needle. This needle is the part that points to magnetic north to help hikers and navigators and others determine direction. With a surveyor\’s compasses, additional tools are added to help with measurement. A sighting device is mounted onto the surveyor\’s compass and placed onto the north-south axis. From there, you would mount this compass onto some form of tripod and sometimes on a Jacob staff prior to use.
The Jacob staff actually refers to more than one device. In some cases, one would hold a Jacob staff and use it for mathematical calculations. This type of Jacob staff would be held up just below one\’s eyes and was used by astronomers and also was a helpful tool for sailors. This type of Jacob staff dates back to the 14th century and was invented by a renowned mathematician. When it comes to surveying, the Jacob staff is simply what you would mount your surveyor\’s compass on to hold it steady, and it was commonly used for this purpose from the 1800s and still is used today.
There are many devices that can be supported by a Jacob staff in addition to a surveyor\’s compass. Other types of compasses, such as a forester\’s compass, might be mounted on the Jacob staff. You also might place an Abney level on a Jacob staff or perhaps a device known as a graphometer, which is yet another surveying instrument that can be used to measure angles.
While a Jacob staff is a handy choice when using lighter weight devices such as the surveyor\’s compass or a graphometer, heavier devices should be mounted onto a sturdy tripod. The theodolite and the total station, both of which are commonly used by surveyors and engineers to record measurements, can be very heavy and a tripod is a much better option.