Category Archives: Surveying

Columbia River surveys_09

Survey. Dredge. Repeat: Keeping the Columbia River Navigable

As the skipper of Galileo 3, a 30-foot sailboat on the Columbia River, I tell my crew that I am comfortable with 15 feet of water under the keel, get nervous when it drops below 10 feet, and take immediate action if it drops below 6 feet. That’s because I cannot constantly monitor my chart...

color contour map

CGVD2013, Part 2

Above picture:  This color contour map shows the difference between CGVD2013 and NAVD 88, especially of interest to those who work on projects along the U.S./Canada border. In part 1 of this series in xyHt’s October issue, Canada’s new vertical datum is introduced—CGVD2013— with an overview of past Canadian datums, directions during the current transition...

geological colorado map

The Hayden Example

Igor Kidinsky—known on this survey crew as Eager (The Kid)—carried the shovel and pick. Glenny Dale—known as Glutton (The Old Man)—carried the plans and metal detector. They had been looking for block corners and had found a mixture of old and new pins. Now they were looking for interior lot corners and came upon a...

Round London

A Re-imagined “24 Miles Round London”

Kristjana Williams, an Icelandic artist who lives and works in London, is fascinated by maps, mythical creatures, and Victorian engravings. She brings historical works of cartography back to life using vibrant, digital collages. Pictured here is her interpretation of Daniel Paterson’s “24 Miles Round London” map, originally published in 1791. Paterson’s map presents London’s surrounding...


A Pennsylvania Traverse Low-Distortion Projection

This article coincides with the December 2014 xyHt print article, Transformation of Observations – Part 2. In the September 2013 issue of Professional Surveyor is Dr. Charles Ghilani’s excellent article entitled “Grid versus Ground.” The article demonstrates the error created by ignoring elevation in traverse computations and describes the numerical and logical errors inherent in...

Out of Many, One

Artful GNSS

Things in the nation’s capital can happen quickly, but only when the parties involved agree to work closely together towards a common goal. Internationally renowned artist Jorge Rodriquez-Gerada was given six months to develop a plan and complete a six-acre painting using sand and topsoil. His canvas would be an incredibly high-profile piece of National...