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GPS for Disaster Operations

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Objectives

  • Explain FEMA’s use of coordinates.
  • Explain basic GPS theory as applied to actual field use.
  • List common problems and their prevention.
  • Demonstrate the ability to configure the unit, obtain, record, and verify coordinates in the field.

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Introduction

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Course Content

  • Section 1 Introduction
  • Section 2 Mapping and GPS Theory
  • Section 3 Unit Features
  • Section 4 Field Operations
  • Section 5 Practical Exercise
  • Section 6 Quality Control
  • Section 7 Summary

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Evolution of GPS

  • 1978 NAVSTAR
  • 1980 Civilian use
  • 1995 Full Constellation
  • 2000 Selective Availability turned off
  • 2005 Additional Bands
  • 2010 30-50 cm accuracy

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FEMA use of GPS Information

  • Often no physical address
  • Federal Grants requirement
  • Damage location validation
  • Special considerations
  • Flood Plain mapping
  • Repetitive loss rule

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Who uses GPS information?

  • Response – PDA
  • Public Assistance – Project Worksheet, compliance
  • Mitigation – site survey, flood plains
  • Historic – Special maps (burial sites, districts)
  • Environmental – Special maps (species, wetlands)
  • GIS – special projects, creating maps
  • Headquarters – long term tracking & analysis

FEMA Requires Accuracy of 20 Meters

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Example of Use

FIRM

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Current FEMA Performance

  • 20% PW correctly entered coordinates
  • Common mistakes
    • Transcription errors
    • Wrongly formatted
    • Bad Conversions

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Target Performance Goal: 95% Correct

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Section Two

Mapping and GPS Theory

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An Overview of Mapping

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Map Grid

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World View

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Grid Formats

  • FEMA Format Decimal Degrees hddd.dddddo

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  • Degrees Decimal Minutes
    • hdddomm.mmm

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  • Degrees, Minutes, Seconds
    • hddomm’ss.s”

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  • Universal Trans Mercator

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  • US National Grid

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N 38.04417°

W078.49839°

17S QC 19520

MGRS 13669

N 38° 02.650’

W078° 29.903’

N 38° 02’ 39.0

W078° 29’ 53.9

17S 0719520

4213669

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Effects of Wrong Format

  • NEMIS only accepts hddd.ddddd
  • GPS default setting for hdd mm.mmm
  • N 36 50.8439 W 75 58.7067 entered as N N 36.508439 W 75.587067 results in 51,318 meters of error (31.88 miles)