Triangulation
Rectangular Coordinates
- Triangulation is used for interior measurements, both indoor and outdoor
- The measurements must be taken from 'permanent' landmarks, such as poles or mailboxes
- Regular evidence- does not change shape when moved
- Irregular evidence- fixed using 2 measurements
- Rectangular coordinates represent clear boundaries/interior walls
- 2 measurements are taken at right angles from center mass of the evidence to the two nearest walls
- The origin of evidence can be altered by rotating on an axis where the 2 measurements intersect
Baseline Coordinates
- Baseline coordinates can be used indoors or outdoors
- The Baseline is a line that cuts off part of the room or area that isn't involved in the crime scene
- Baseline Coordinates tell someone where an object is in the room off of the Baseline
Sketching Views
- 4 different types
- Overhead
- Elevation (heights)
- Cross-projection ('lays' the walls down to map objects of interest)
- 3D view
Conclusion
Total Station
A big camera used in car accidents and other types of scene reconstruction
Polar Coordinates
If items(or body parts) are scattered in a large field, a right angle from two points is used to locate evidence
Crime Scene Sketches
Grid Station
The same as Polar Coordinates, except when there are no substantial landmarks
There are various methods that involve mapping out a crime scene,each showing important aspects of physical evidence
- A crime scene sketch maps out important physical evidence in the investigation
- Rough & smooth and finished sketches
- Forensic mapping records the precise measurements of the evidence to be drawn from the scene
- Any errors from the sketches could put the whole investigation in jeopardy
rough crime scene sketch
Crime Scene Sketching and Forensic Mapping
By: Sammantha Lilly and Jordan Rumney