Nepedia
Back to Discover
Advanced Reader
💻

Plane table

technology Maturity 7-9 Next article →

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.

Plane table cgs00426
Plane table cgs00426

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.

Plane table cgs00426
Plane table cgs00426

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.

US Army Corps of Engineers Map Making, World War I
US Army Corps of Engineers Map Making, World War I

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.

US Army Corps of Engineers Map Making, World War I
US Army Corps of Engineers Map Making, World War I

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.

681 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (2)
File:US Army Corps of Engineers Map Making, World War I.jpg
US Army Corps of Engineers Map Making,...
File:Plane table cgs00426.jpg
Plane table cgs00426.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.