Plane table

A plane table is a special tool.

It has a flat top and a strong base. The base has three legs. These legs help it sit on bumpy ground. You can move the legs to make it level.

A person puts paper on the table. They use a tool called an alidade. This tool has a sight to look at things. It helps them draw straight lines.

This tool helps people draw maps. It is easy to use. People can draw maps without hard math.

It is a very handy tool for making maps.

A plane table is a tool used to make maps.

It provides a flat and level surface for field drawings. The name "plane" means the table is level and horizontal. The table has a smooth top and a strong base. This base is a tripod with three legs. You can change the leg lengths to sit on bumpy ground. You can also use bubble levels to make the top perfectly flat.

To use it, you attach a sheet of paper to the top. You use a tool called an alidade to see objects. An alidade is a rule with a telescopic sight. This sight helps you draw straight lines toward things you see. You can also use it to find the height of the land. Some tools use stadia marks in the telescope to measure distance.

This tool became very popular for surveying. It is easy to use. People can draw maps using shapes instead of hard math. In 1890, Sebastian Finsterwalder added a camera to the table. This helped start photogrammetry, which is a way to map using photos.

A plane table is a special tool used for making maps.

People use it for surveying and exploring new lands. It helps them make charts for coastal navigation too. The main job of the table is to provide a flat surface. This surface is used for field drawings and maps. The word "plane" means the table is level and horizontal. This makes it a very steady place to work.

Setting up the tool is a careful process. First, you place a sturdy tripod base over a specific point. The tripod has three legs to support the table. You can adjust the length of these legs on rough ground. This helps the table stay steady on bumpy terrain. Next, you use bubble levels to make the top perfectly flat. A drawing sheet is then attached to the smooth surface.

To draw the map, you use a tool called an alidade. An alidade is a rule that often has a telescopic sight. You use the sight to look at objects of interest. Then, you draw a line on your paper in that direction. You can also use the alidade to find land elevations. Some alidades have stadia marks in the telescope to measure distance. This lets you record information directly on your drawing.

We have many records of this tool from long ago. The earliest mention was in 1551 by Abel Foullon in Paris. He wrote about a fully developed version of the instrument. In 1590, Cyprian Lucar used the first English name for it. A Swiss maker named Leonhard Zubler wrote about it in 1607. He called it an Instrumentum Chorographicum. He credited the invention to a man named Philipp Eberhard.

This tool became very popular because it was easy to use. Some people thought it was simpler than a theodolite. It let people use drawings instead of hard math. This was helpful for people with less education. In 1890, Sebastian Finsterwalder added a camera to the table. This helped start photogrammetry, which is mapping with photos. This change helped surveying in both space and time.

A plane table is a specialized instrument used in several important fields. It is essential for surveying, site mapping, and exploration mapping. Experts also use it for coastal navigation mapping and related disciplines.

The primary purpose of the device is to provide a solid and level surface. This surface allows a person to create field drawings, charts, and maps directly in the field. The term "plane" refers to the fact that the table is kept flat and horizontal. Before 1830, the device was often called a "plain table." This older name likely reflected the simplicity of the tool rather than its physical flatness.

To understand how a plane table works, you must look at its construction. The device consists of a smooth table surface mounted on a sturdy base. This base is typically a tripod designed to support the table over a specific point on the ground. Because land is rarely perfectly flat, the tripod is very important. One can adjust the length of the tripod legs to compensate for rough terrain. This adjustment ensures the table remains steady regardless of the ground's shape.

Once the tripod is in place, the user must achieve a precise horizontal level. This is done using bubble levels located on the base. Once the table is level, a drawing sheet is attached to the smooth surface. The user then employs a tool called an alidade to map the area. An alidade is a rule that often features a telescopic sight. By looking through this sight, the user can aim at specific objects of interest. They then draw a line on the paper that follows the direction of that object.

Mapping involves more than just drawing lines for direction. The alidade can also function as a surveying level. This allows the user to record information about the topography of a site. Topography refers to the physical features and elevations of the land. Users can record these elevations directly onto their drawings. Furthermore, distances to objects can be measured in different ways. A user might measure them directly, or they might use stadia marks. These marks are built into the telescope of the alidade to help calculate distance.

History provides many clues about the origins of this instrument. The earliest known mention dates to 1551 in Paris. It appeared in a work by Abel Foullon called "Usage et description de l'holomètre." Because Foullon described a fully developed instrument, it was likely invented even earlier. In 1590, Cyprian Lucar provided the first mention of the device in English. Later, in 1607, the Swiss maker Leonhard Zubler published an account in "Novum instrumentum geometricum." Zubler called the device an "Instrumentum Chorographicum." He credited its invention to a fellow Swiss maker named Philipp Eberhard from Zurich.

There has been some debate regarding who actually invented the plane table. Some historians have credited a Nuremberg mathematician named Johann Richter. This mathematician was also known by several other names, such as Johannes Praetorius or Vai. However, this claim appears to be incorrect according to some sources. Despite these debates, the plane table eventually became a very popular tool for surveying. It was widely taught to many different types of users.

One reason for its popularity was its ease of use. Some professionals considered it a substandard instrument compared to the theodolite. This was because the theodolite is more complex. The plane table allowed users to use graphical methods for their work. This meant they could draw their findings rather than relying on difficult mathematical calculations. This made the tool accessible to people who had less formal education.

In the late 19th century, the technology of the plane table changed significantly. In 1890, Sebastian Finsterwalder worked to improve the device. He added a camera to the plane table in conjunction with a phototheodolite. This innovation established the field of photogrammetry. Photogrammetry is the science of making measurements or maps from photographs. This development allowed for more advanced surveying in both spatial and temporal contexts. This connection between photography and mapping changed how we understand the world's physical changes over time.