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2 variations in creating a sketch to document evidence on vertical objects
- cross-projections or exploded view
- elevation sketch
how do you fix measurements to surrounding walls in rectangular coordinates
by measuring at right angles from evidence to surrounding walls
when is baseline appropriate
exterior scenes without evident landmarks
when are rectangular coordinates on a grid effective
in gravesite excavations
when should you use triangulation on a baseline
exterior crime scenes where the field of evidence is not too widely scattered, but there are no adequate landmarks
why is it unnecessary to orient a total station to true north?
the accuracy of the total station is ridiculously good
3 things all narratives need
- 1.detailed with all pertinent facts and conditions documented.
- 2. accurate with few inferences or subjective evaluations included
- 3. understandable- logical and organized
why should you mark investigative efforts that yield no results
to show that effort was expended- lawyer might say there was inappropriate or improper procedures
documenation four key elements
how does f-stop affect the resulting photo
1.smaller f-stop =more light the lens allows in
how to prevent overexposure or bleaching out of close-up photos
the use of offset flach and oblique lighting in these situations will correct and eliminate this
What can ISO do?
the higher the ISO= more noise= bad photo
What is the temp. of light measure in?
What is roadmapping?
patterns overall orientation in the scene and entire pattern (for bloodstain pattern analysis)
f-stop higher=smaller aperture=less light
what does depth of field do?
relates to the focus of items
what do fill-flash techniques do?
ensrue consistent lighting across the spectrum.
3 key elements to consider when evaluating a luminol reaction
what is a positive reaction to blood?
blue-green, should iniate in a matter of seconds, and remain active for several minutes
what are the three types of evidence that the firearms examiner looks for?
- 1. layering of trace evidence, indicative of sequence of targets struck
- 2. damage to the projectile, indicative of the type of target the bullet struck
- 3. deformation of the projectile, indicative of the angle of impact
why is effective documentation necessary for bloodstain patterns and bullet defects?
important do destinguish between pieces of evidence. proper numbering is important
If you are not sure if the defect is from a bullet what test can be done?
chemical tests for examining the presence of copper and lead
What is meant by "origin and cause" when discussing fire scene investigation?
Determine fire flow and that will help indicate the origin of the fire
What way does firefighting activity affect the fire scene investigation?
by forcing entry into buildings, vent areas by breaking out windows, tear down walls, or move objects and furniture