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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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