Hi,
OPD beat map you have does have bering on the radio identifiers. A typical OPD identifier consists of three segments. for example: 1L26 and the last numbers correlate the beat or supervisory level.
Break down 1-L-26
first number:
1 is midnights
2 day shift
3 is swing shift
4- special operations (aircraft for example)
5- Tac unit- street crime suppression with no beat responsibilities.
7 are traffic or motorcycle units
11 are generally civilians crime scene techs or dogcatchers.
31 are park rangers/park police officers
33 are school district police officers
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second segment a letter
L- solo uniformed patrol in marked unit
A- two man uniformed patrol in marked unit.
Tac- uniformed or soft clothed officers generally in a low profile car.
C- are generally non-sworn folks like crime civilian crime scene techs and dog catchers
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last digit/s designate beat for officers and rank/function for ranks above officer.
so a 2 here would mean beat 2 and a 26 would mean beat 26 which correlates directly yo your map.
71 series units are sergeants, sergeants are further broken down by districts Of which there are four i think) 71 supervises district 1, 71 district two etc.
81 are lieutenants
91 captain/generally the watch commander
so as in the example; 1L26 would be midnights (aka 'dog watch'), solo patrolman/person working beat 26.
26 is in district 3 so he would supervised by 1L73 (District three sergeant) who is supervised by 1L82(Lieutenant for districts 3/4) who answers to 1L91 Captain/Watch Commander(God).
Helicopter is 4A50 or called 'Argus' from days old.
Now have fun with their 9 code.