[music] Narrator: Since the beginning of time, the
Earth's surface has shaped human life.
The effects of elevation are essential to where and how we live, the risks of living
where we do and the impact we have on the local environment.
Digital elevation data helps us interpret and analyze physical features of the landscape
for scientific studies.
It allows us to see the surface of the Earth in three dimensional views.
Jim Mauck: Elevation data has been an important component of the US Geological Survey's topographic
maps since the 1880's.
A topographic map without elevations in the form of contours is simply not a topographic
map.
Digital elevation models, or DEMs, are collected into a single, multi resolution dataset known
as the National Elevation Dataset.
As the elevation source for The National Map, the NED provides up to date bare earth data
that describes the Earth's relief.
Narrator: LIDAR is the NEDs primary source of new elevation data.
It's cost efficient, more accurate, and it captures data points from the Earth's surface
to the tops of the features above and in between.
Jim: Its use goes beyond topographic mapping into other areas of science and into everyday
life.
David Maune: FEMA produces flood insurance rate maps that let homeowners know what their
risks are of flooding, and LIDAR is essential in making accurate flood maps.
FEMA uses hydrologic modeling and hydraulic modeling for their flood studies.
The credibility of the National Flood Insurance Program is largely based on the credibility
of the elevation data used to produce those flood studies.
FEMA computes the water surface elevations for a standard flood event such as a 50 year
flood, a 100 year flood, a 500 year flood.
What the homeowner wants to know is, what is their risk of flooding?
How the special flood hazard area changes depending on whether or not you used accurate
LIDAR data in that flood study.
New flood studies done with more accurate LIDAR data tells more people they need to
buy flood insurance or in some cases fewer people need to buy flood insurance.
LIDAR is the basis for making flood maps accurate.
Karen Schuckman: In the fall of 1999, Hurricane Floyd hit North Carolina.
It was one of the most damaging storms in recorded history.
Particularly flooding caused most of the damage.
At that time LIDAR was just emerging as a potential technology for collecting accurate
elevation data very quickly.
One important lesson learned from the North Carolina project was there were many, many
other potential users of the data.
To find a way to archive, store, distribute, make all that data available in an efficient
way really challenged the existing infrastructure, and that's where the USGS really had an important
role to play because of their experience with managing large amounts of data over large
areas and distributing it to the public.
Mike Renslow: One thing about LIDAR that's also amazing is everything is in the right
place, you know.
It's in its true location natively.
So it's 3 D and it's in the right place.
With this it totally revolutionized the way that we measure forest lands because now we
have a tool that gives us everything we need.
How do we manage this forest?
Based on the density of certain kinds of vegetation, how do we best manage it for certain kinds
of wildlife habitat or an endangered bird species habitat?
When we look at where we are today, when we start to consider things like climate change,
when we start to think about where the carbon is in the forest, we now have some reliable
information that we can actually use to drive the science to determine how do we mitigate
these problems.
Jim: Through support and partnerships, the elevation data available to The National Map
continues to grow and improve, but we have a ways to go.
A federally funded assessment is currently underway to better understand the requirements,
costs and benefits across all levels of government and business for elevation data.
Beyond helping to lessen the impact of natural catastrophes, new and improved elevation data
fosters new scientific uses and applications that eventually filter down to the general
population.
Fostering the use of this data is the goal of the Elevation Program of The National Map.
Narrator: Go to NationalMap.gov to learn more about how to use elevation information
or to become a valuable partner.
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