CAN’T WAIT?    Let’s get started (!!)

By Mick Capman,
PSFM President (Kalamazoo County Sheriff – Retired)

First of all, after having chosen your preferred RP, set up the tripod.  Position one of the tripod legs towards the core or majority of evidence at the scene.   

Second, position the tripod legs such that the “face plate” appears level to the eye (looking at it from more than one position), as seen here.

Third, position yourself between one of the sets of tripod legs (as seen in forefront position of below photo) and position the “leveling foot screw” (one of three found on the tribrach) at a ‘neutral’ or common setting position.  This will appear as a ‘scribed mark’ on the foot screw itself. 

Fourth, level the Instrument as seen being done by other troopers in the below photo.  There are many good ways to level the instrument effectively & quickly.0 

 

Notice below, the detective adjusting his “leveling foot screws”:

 

Fifth, point the Instrument towards a northerly direction* for zero(0)-setting. It is a generally accepted practice in the field for commencing all horizontal angles from a “generally known compass position” of zero. 

Horizontal angles, as you recall, are important for showing relationships between like and/or other evidence pointsVertical angles are generally pre-set/defaulted by the manufacturer, with the ‘zero’ point found directly overhead or up.  Vertical angles, etc. are calculated by EvR to show “changes to the lay of the land” (topography). 

It is a given that all slope distances commence with ‘zero’ being at the Instrument.  Ergo, all measurements (2-angles & the distance) begin at ZERO (just like distances do on other conventional means of measurement  ... i.e. steel/cloth tape, etc.).

  • Sokkia FMS530r3 (as of 11/04) Press FUNC button, then the F2 button twice, then the FUNC button again.  Take time to examine the screen and become accustom to its general appearance and settings.
  • Leica FMS407       (as of 01/03) Press the F4 button until Hz=0 is seen over F2.  Then press F2 button twice, then the F4 button once.  Take time to examine the Instruments screen and become accustom to its’ general appearance and settings.
  • Other Models? Email mapscenes@aol.com for steps

Truthfully, you do not want the “zero set” function button to be too readily accessible ~ guess why?!!   If it is accidentally pressed at any time while doing your important scene, it will cause all horizontal angles to be terribly off and the relationship of evidence, one to the other, will be in error!  AVOID, at all cost, re-zero setting at any time once the scene documentation has started.

Sixth, the Reference Measurement Protocol.  Position the zero-end of the measuring tape at the ground RP point directly below the Instrument.  Turn on laser plummet or look through optical plummet to determine this point, and stretch out the tape and measure to a reasonable distance (20, 25, 30, 50, 100+ feet). 

Position a prism pole (or mini-prism on sectional pole) at that measured location.  Then, using the “rough sight” on Instrument’s scope POINT the Instrument towards the target (prism).  Now, AIM the Instrument by lining up cross-hair in Instruments reticle to that of the prism.

Interior and other ‘unique’ scenes present a different consideration in this regard.  Other considerations regarding this process can be found elsewhere at this website.

 

a handy use of sectional prism pole is for positioning RM location.

Seventh, create a Rough Sketch of the scene.  This very helpful aid permits a written record of your diagramming procedure and can be used, for memory’s sake, to assure you that all criminal evidence has been accounted for.  And it is a vital part of basic, Police/law enforcement investigation practices.

Eighth, setting up the EvR for scene work. J  Just follow these simple steps:

1-     power up device (TDS, Panasonic, Tracker)

2-     tap icon to enter EvR software

3- Tap Create New Scene, press OK

4- Fill in Scene Name, press OK

5- Optional dialog box, press Ok

6- Tap Reference (found at screen bottom or top)

7- Tap Occupy Reference Point (as shown here)

             8- Measure Total Station Height (to mark on side of Instrument).


           
        

9- With Instrument POINTED towards prism (or other specific point), AIM Instrument with such that it’s cross-hair is precisely in the center of the target.

          10- Tap Shoot Angles and Distance button

                  

         11- Input where prompted, the Target Height (as shown here), press OK

           

You should now be ready to begin the scene documentation process!! J  First document, if you choose, “short lived” evidence points (body location, shell casings, etc.).  Exclusively use the “Pnt” input-window for labeling these sorts of evidence: 

You may also “pre-select” your perceived LINE-codes to be used at the scene.  For example, you may choose multiple edge of pavement (EP) codes, or gravel edge (GE), fog line (FL), Yellow center line (YL) codes, or skid mark (SM), yaw mark (YM), gouge (GOU), debris line, steering (power & trailer) wheel-axle line codes, etc. etc., as seen here:

Whew …!!  that could have been a pretty BIG scene or one of just a few points.  And now that you feel you have documented all that is/was important ~ knowing all the “issues at hand” and are ready to tear down the Instrument and head back to the office.

Ninth, But before you do that > > take one more “relaxed” look at the scene and go over carefully all that you’ve accomplished.  You can view, on the EvR, close up views of all evidence ‘shot’ etc.  Just make sure for yourself that all has been documented.  ‘Stuff’ won’t be there when you return the 2nd time if something is now forgotten!!!!   Murphy’s Law takes over in that regard!

And finally Tenth, we’re ready now for our last RM (reference measurement).  By using the rough sight, POINT the Instrument back toward the RM.  AIM the Instrument using the Horz./Vert. fine-adjustment knobs and line up reticle cross-hair to that of the specific object or prism.

Code the EvR as a RM and take the ‘shot’.  Once this step is complete and, assuming all other things/considerations are equal (!), you can start to put equipment away.

If total station has become wet for any reason, wipe off with a towel and let it later “room dry” out of its box.  Wipe dry too the storage box.

Good Luck and we’ll see you at the next scene! If we can help, give us a call.
 
 
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