Roadmap to Resources
The National Geodetic Survey (NGS) develops and maintains a national system of positioning data needed for transportation, navigation, and communication systems. NGS also implements a coastal mapping program, conducts aerial photography surveys, develops standards for conducting geodetic surveys and assists state, county, and municipal agencies throughout the United States with training workshops.
The Web pages listed below are a
small selection of the information and technical resources provided
by NGS and similar organizations around the world. Many more resources
are accessible through the NGS Web site
In addition, some of the Web pages listed reside within
larger Web sites. You may wish to browse through these Web sites and
examine other available resources.
The National Geodetic Survey - What it
NGS: Positioning America For the Future
This Web page provides a brief overview of the National
Geodetic Survey (NGS). On the right hand side of
the page are links where you can download short descriptions of many
NGS programs (PDF format) including the Ionosphere Mapping Program,
the Height Modernization Program and the National CORS Program. If
you scroll to the bottom of this page, under the heading "So,
What is Geodesy? Who Needs it and Why?" there
are links to excellent materials (PDF format) explaining
the role of geodesy in contemporary America, and
two very good on-line geodesy tutorials.
NOS Web Site News Feature on NGS Activities
Web page briefly describes the National Spatial Reference System (NSRS), the
Global Positioning System (GPS), and the NGS Height Modernization program. The
page discusses the importance of geodesy and provides links to related geodetic
programs and downloadable information.
The History of the National Geodetic Survey
Web site provides a wealth of information on the
history of the National Geodetic Survey and its
evolution from the Survey of the Coast, the United
States first civilian scientific agency, formed
by Thomas Jefferson in 1807. In addition to over
600 pages of reader-friendly text, there are links
to historical photo albums, short stories about
geodetic expeditions, as well as historical maps
and charts. A must see !
The National Geodetic Survey's Continuously
Operating Reference Station (CORS) Web Site.
is the official Web site of NGS's continuously
operating reference stations (CORS). Surveyors,
geographic information system (GIS) professionals, engineers, scientists,
and others use data from the CORS system to assure horizontal and vertical
positioning accuracies within a few centimeters.
A central feature of this Web site is a "dynamic" map of the United States and its territories. The different symbols and colors on the map indicate the locations and sampling rates of hundreds of CORS stations in the United States' network. By selecting and "clicking" on an area of the map you can "zoom" into a region where a CORS receiver is located. By selecting and "clicking" on
a specific receiver, you can view a detailed area map showing the receiver's
exact location, see photographs of the receiver, and view coordinate
data that the receiver is collecting from Global Positioning System satellites
in real time.
When a specific receiver has been selected,
you can obtain different kinds of information about
it from the menu on the left hand side of the Web
page. Just select the information you would like
to see and then "click" the submit button.
Ecosystem Health and Land Loss in the Chesapeake
this Web site dates back to 1997, it demonstrates
how geodetic and other monitoring techniques
can be used together to determine the health of the Chesapeake Bay ecosystem.
The project description includes sections on sea level variation, land
subsidence, remote sensing of coastlines using satellites and GPS. Each
section of the project is accompanied by enhancing graphics and images.
Web page links to definitions, descriptions and
research about the geoid. The link to "What is the Geoid" is
geared to the general public and is accompanied
by several good images. While most links on the page present information
better suited to individuals with specific training
in the geodetic sciences, there are many excellent images and kernels
of information sprinkled throughout this pages links.
The Canadian Geodetic Survey Division - What
tutorial is offered by the Geodetic Survey Division
of Canada and includes information on geodesy,
GPS, the geoid, surveying, and gravity. The tutorial
is accompanied by well-developed graphics. You
can select these and other subjects by "clicking" on
them from the menu of topics on the left hand side
of the Web page.
Links to Additional Resources
This portal Web site offers links
to many geodetic resources including government
agencies, university programs, scientific organizations,
and international institutes. Many of these organizations
offerings are very technical in nature however,
there are hidden gems to be found within the
list of links; for example, were you aware that
the United States Department of Defense has a
directorate of time ? Check out: http://tycho.usno.navy.mil/ and
other links here.