Structural Collapse Awareness
U.S. National Grid
Structural Collapse Awareness
Objectives
In this lesson you will learn how to:
• Understand and read USNG
coordinates
• Identify locations by using
grid coordinates
• Relay grid coordinates in
reference to a given location
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Structural Collapse Awareness
Background
The USNG ensures a uniform
grid mapping system across
cities and counties in Florida
and can be easily extended
world-wide as a grid reference
system.
Additional information about
the USNG can be found at:
www.fgdc.gov/usng
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Structural Collapse Awareness
Features of the USNG
USNG expands the utility of street and other maps
by adding the following commanding features:
• Provides a grid reference system that is seamless
across jurisdictional boundaries
• Is the foundation for a universal map index
• Describes point locations on appropriately gridded
paper and digital maps
• Allows geo-positioning using Global Positioning
System (GPS) receivers
• Supports World Wide Web map portals that link digital
maps and GPS data
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Structural Collapse Awareness
Longitude and Latitude
Using longitude and latitude can be confusing because
different agencies cite different coordinates to identify the
same location.
All of the longitude and latitude coordinates
below describe the same location:
• DD -85.990151, 30.272240
• DM -85 59.409089, 30.16.334386
• DMS 85 59’24.545”W, 30 16’20.063”N
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Structural Collapse Awareness
USNG Overlay
As a responder, you may be
given a map or an aerial
photograph of the response
area with a USNG overlay.
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Structural Collapse Awareness
USNG Coordinates
The first step in reading a USNG map is to
understand the letters and numbers that make
up a grid coordinate.
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Structural Collapse Awareness
Grid Zone Designation
17R LL 573 918
The 17R is the Grid Zone Designation (GZD) for a
world-wide unique address.
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Structural Collapse Awareness
Meter Square Identification
17R LL 573 918
The LL is the 100,000 Meter Square Identification for
regional areas.
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Structural Collapse Awareness
Easting and Northing
Grid Coordinates
17R LL 573 918
The numbers 573 918 are the Easting and Northing
coordinates of a specific location.
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Structural Collapse Awareness
Easting and Northing
Number of Digits
The more digits used, the smaller the grid coordinates and
the more accurate the location.
• 57323 91820
• 5732 9182
• 573 918
• 57 91
10 digits locates the area within a
1 x 1 meter square
8 digits locates the area within a
10 x 10 meter square
6 digits locates the area within a
100 x 100 meter square
4 digits locates the area within a
1000 x 1000 meter square
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Structural Collapse Awareness
Knowledge Check
Given the coordinates 17R NN 17938 01505 what is the
100,000 Meter Square Identification for regional areas?
a.17R
b.17R NN
c. NN
d.17938 01505
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Structural Collapse Awareness
Knowledge Check
You are responding to an area flooded by the storm surge
during Hurricane Michael, and were given the coordinates
6612 5811. What size area will you be able to locate with
these coordinates?
a.1 x 1 meters
b.10 x 10 meters
c. 100 x 100 meters
d.1000 x 1000 meters
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Structural Collapse Awareness
Area Identified with a USNG
Coordinate
14
Structural Collapse Awareness
Knowledge Check
You are given the coordinates of a rescue team on-scene
as 507 030. Find and mark this location on the map.
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Structural Collapse Awareness
Knowledge Check (Answer)
You are given the coordinates of a rescue team on-scene
as 507 030. Find and mark this location on the map.
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Structural Collapse Awareness
Identifying the Coordinates
of a Known Location
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Structural Collapse Awareness
Knowledge Check
This map is labeled with
points A and B. Identify the
coordinates for the location
of Point A, your location.
a. 572 914
b. 571 913
c. 913 571
d. 914 572
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Structural Collapse Awareness
Knowledge Check (Answer)
This map is labeled with
points A and B. Identify the
coordinates for the location
of Point A, your location.
a. 572 914
b. 571 913
c. 913 571
d. 914 572
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Structural Collapse Awareness
Knowledge Check
A nearby rescue crew has
located additional victims
needing immediate attention.
Your crew has been asked to
report to the other crew’s
location at Point B. Identify
the coordinates in which
you’ve been asked to report.
a.578 915
b.578 921
c. 917 578
d.577 917
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Structural Collapse Awareness
Knowledge Check (Answer)
A nearby rescue crew has
located additional victims
needing immediate attention.
Your crew has been asked to
report to the other crew’s
location at Point B. Identify
the coordinates in which
you’ve been asked to report.
a.578 915
b.578 921
c. 917 578
d.577 917
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Structural Collapse Awareness
Summary
In this lesson, you have learned:
• Why the U.S. National Grid
(USNG) was developed
• How to find a location within
a devastated area if given
the USNG coordinate
• How to read a USNG to find
and relay the grid coordinate
for a location
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