What is a Dumpy or Automatic Level
look at the history of surveying levels. Since the Dumpy level was
invented in early 1700's it has been considered the standard, that was
up until around the 1830's when the transit level was invented.
Recently the level has changed faster than you can keep up with it, but
through all this the Dumpy level has remained a reliable back up just
in case the modern levels breakdown.
A dumpy level, builder's auto level, leveling instrument or automatic level is an optical instrument used in surveying and building to transfer, measure, or set horizontal levels.
The level instrument is set up on a
and, depending on the type, either roughly or accurately set to a
leveled condition using footscrews (levelling screws). The operator
looks through the eyepiece of the telescope while an assistant holds a
tape measure or graduated staff vertical at the point under
measurement. The instrument and staff are used to gather and/or
transfer elevations (levels) during site surveys or building
construction. Measurement generally starts from a benchmark with known
height determined by a previous survey, or an arbitrary point with an
The Dumpy level was a simple device that was nothing more then a small telescope with a bubble level attached to it. The newer
have a few more bell and whistles but are still the same basic design.
Some of the drawbacks of a Dumpy level are the time it takes to set up
and get level, the slightest mistake in setting it up can result in an
inaccurate reading, and taking more then one measurement from different
directions can be off if not set up perfectly.
A Laser Level And How It Works
is a fairly recent invention, and has changed the way surveying is
being done. With a self leveling laser level you can be assured that
your measurement will be as accurate as humanly possible. A laser level
is a level that uses a laser light to project a line. Most surveying
laser levels us a rotating mirror so that they can project a horizontal
plane around in a circle. A laser level is more accurate then a Dumpy
level but can break down from time to time.
As its name suggests, a
is a leveler that illuminates a horizontal plane using a laser. It was
originally developed by an inventor named Steve Orosz. The laser level
works by being stationed on a tripod. This projector also has a
rotatable head with a mirror, so that the laser beam can also sweep
across the vertical axis. It is adjusted through the many visually
interpretable level vials and the numerous screws that must be manually
adjusted by a human for correction projection. Then, a staff with an
operator equipped to it with a moveable sensor, detects the laser beam
and makes an audible signal every time the line is in accordance with
the beam. The key behind the laser level is the position of the sensor
on the graduated staff, as it interprets the elevation differences
between various points on a certain terrain.
There is also a
tower mounted laser level. This is often used together with the wheel
tractor-scraper, which has a sensor attached to it. This is commonly
used during land laser leveling process (such as agricultural lands and
when building the foundations of skyscrapers) to flatten the land at a
certain degree for a functional drainage system.