b dunagan - forensic mapping of fire and explosion scenes with total stations

7/27/2019 B Dunagan - Forensic Mapping of Fire and Explosion Scenes With Total Stations

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Forensic Mapping of Fireand Explosion Scenes with

Total Stations

Brian Dunagan, CSP, CFEI, PMP


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Why is Scene Documentation So Important?

Its an inherent part of the

incident investigation process

and is used in preparing the

report.

Good scene documentation can

help provide irrefutable evidence

of root and contributing causes.

Establishes the precise location

and relationship of objects and

evidence at the scene.

Scene documentation is

discoverable and will be closely

scrutinized in the event of legal

proceedings.


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How are Scenes Documented Now?

No mapping or diagrams

Low precision guesses

Feet (literally)

Tape measures

Measuring wheels

Laser distance meters

GPS

Total Station

Laser (LIDAR) Mapping


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What is a Total Station?

A Total Station is an electronic

surveying instrument that has

an integrated computer and

can measure angles in thehorizontal and vertical planes,

util izing a laser. This is

especially useful because

changes in elevation are very

difficult to both measure anddepict on a scene sketch.

The Total Station is capable of

recording evidence positionsin three dimensions, thus

simplifying an otherwise

complicated situation.


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The Other Equipment

Data Collector

Prism

Rod

Tape Measure

Compass

Reconstruction Softwareor CAD

Assistant


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When is Precision Mapping a Great Idea?

Large or complex scenes

Time crit ical (weather,

operational

considerations, etc)

Measurements are not

readily attainable by

normal means (vertical

distances, over water, etc)

Irregular shapes or

patterns (spil ls, burn

patterns, skid marks)

Litigation or other legal

proceedings are likely as a

result of the accident


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How Would You Diagram or Sketch This Scene?


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Benefits of a Total Station?

Accurate to within

approximately over a

1 mile distance.

Very rapid data

collection.

Collects an electronic

record of your scenedocumentation efforts.

The data collected can

be used directly by CAD

and animation software.

Gold standard for traffic

accident investigation

and major lossincidents.


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Disadvantages of a Total Station?

Overkill for most small or

simple incident scenes.

More expensive than tapemeasures and similar

devices.

Successful mapping with

the equipment requiresinitial and continuing

training.

The equipment is waterresistant, not water proof.

Mapping in severe

weather can be

challenging if not

impossible.


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Example of Scene Diagram


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Example of a Basic Animation


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Example of an Advanced Animation


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Points to Remember

Dont assume that

someone else properly

documented the incident

scene (federal, state, orlocal governmental

agencies, insurance

company, subcontractor

companies, etc.)

Garbage in, garbage out

the data collected at the

scene is perishable andprecision documentation

can be critical to a

successful and defensible

investigation.


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Questions?


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IFOGROUP

www.ifogroup.com

[email protected]

b dunagan - forensic mapping of fire and explosion scenes with total stations

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