shrug-l: Numbering Hydrants

Sykes, John John.Sykes at
Mon May 9 09:07:14 EDT 2016

I didn't work out the fine details, but thought that the PLSS Township-Range-Section would be a good start.  That is what is usually used for the first 8 alpha-numeric digits of parcel ID #s.  It gets you down to the nearest square mile, then you could just number sequentially, say from upper right to lower right (back and forth, serpentine-style), same as sections are numbered.  So one hydrant might be 22S-26W-15-33.

Or going one step further, put in the ¼ sections, also numbered from upper right to lower right, into the code, which gets it down to the nearest 160 acres (¼ x ¼ mile), then number sequentially:  22S-26W-15-03-33 (or leave out the hyphens:  22S26W150333).  If you add hydrants, just add the next sequential number in the series, e.g., 34.  This would work for the entire State of Florida.  Your GIS app would then give you the precise map location (lat-long) from this code.

Just a thought.

-- John

From: SHRUG-L [mailto:shrug-l-bounces at] On Behalf Of Rick Labs
Sent: Saturday, May 07, 2016 1:57 PM
To: shrug-l at
Subject: Re: shrug-l: Numbering Hydrants

Scott's hydrant numbering challenge is fascinating. Considered quite a few options and rejected them but found one with some initial appeal:

(For all lat/lon labels I assumed 1 meter accuracy so 6 decimals on the lat and long)

Useless without reader. How to securely attach? Weatherproofing? Overkill for fixed locations? If cable attached the iron hydrant may block the RF?

QR bar code
Could encode a very precise lat lon. However the bar code might need to be fairly large? Fairly high resolution? Not readable by a human without a QR equipped cell phone and none of the handset makers ship them with QR recognition as a standard feature. Perhaps not a multi decade technology winner? Could also print the URL on the label but that would be large.

Unique key number, plus perhaps a check digit
x - perhaps a check digit

However I wanted "the system" to work for any County. So estimated the max at population of County / 3 people per hydrant for a generous upper end estimate. Used Los Angles County as worse case, so need a million hydrant capability. Perhaps overkill.

Then thought, this isn't good at all at County / State boundaries (potential confusion if the neighbors also have a "home brew" hydrant number system)

So...embed State and County:

x - check digit
12- FIPS state code
345 - FIPS county code
000-000  - a unique hydrant key number

This might work, but would it be subject to drifting boundaries over multi decade periods? Plus its long.

lat/lon with 6 decimals
That's a lot for a label, plus its a lot to write down / communicate over the phone. Reasonable font size? Curvature of hydrant?

lat/lon and somehow reduce the digits by assuming it's all in one county
You mark the hydrant xyz County then reduce some digits on the lat and lon that are fixed across the county and assumed. Looked at San Bernadino County and basically you need all the digits in lat and lon so no significant reduction. So, that was a dead end.

Do nothing
no hydrant markings (continue to use prior system)

No coding on hydrant but create a high accuracy ground survey (lat/lon) and make the points .shp file public. Perhaps shoot for Land Survey Marker accuracy.  (Horizontal and Vertical Control Benchmark level accuracy). This could be very handy to have as hydrants are much easier to find vs. embedded markers. Standard disclaimer - not to be used for survey work. (....but to the center tip of the hydrant would in fact be quite accurate).

Then use applications such as Open Street Map to create maps in real time.

Maintenance would need to use the full lat/lon "ID" on service paperwork (long but not impossible if truncated to 6 decimals) Most service people would have or would be moving to cell phones for data entry, so they could see a map and just select the correct hydrant (avoiding the need to key in the lat/lon digits)

lat/long and encode the digits using also letters

Using letters and numbers I think the lat/lon (at 6 decimals of accuracy) can be expressed in just 8 characters!

example 12BY-F89U
Easy to label the hydrant, easy to read and communicate

Here's how I envisioned it:

26 letters to start, but need only 22
ELIMINATE  "O" (number 0), "L" (number 1), "Z" (number 2)
ELIMINATE "Y" (don't need)
01234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ (a total of 32 possibilities)
number above 0-31;  in binary 00000 to 11111 (5 bits per character)

Convert lat long to binary as follows, use position to imply decimal.
sign of lat    1 bit
lat integer (3)    8 bits (use 3 digits for consistency, yes it could fit in 7 bits but not much savings)
lat decimal (6)    10 bits
sign of lon    1 bits
lon integer (3)    8 bits
lon decimal (6)    10 bits
spares    2 bits
Total    40 bits

characters hold    5 bits
characters needed    8

The conversion alog is simple and quick, can be expressed in Excel, run on a cell phone, executed in any Javascript in a browser.

Just one caution (easily checked and avoided during assignment) - letters sometimes form words some words might best be avoided (very rare but possible)

Come to think of it, that coding would be a nice replacement to Zip code. One meter accuracy could "hit the mail box")

Optional add on
If you are going to the expense of marking each hydrant perhaps add a bit more info:

Report any issues
If emergency call 911 with above 8 character code.

Website instantly returns nearest cross street, standard precision (6 decimals) and high precision coordinates (lat/long/altitude) of that particular hydrant. Presents interactive web form for further needs. Something like:
Medical / Ambulance / EMT

Mechanical issues:
Potentially life threatening
Active leak - major
Broken / not functional / missing parts
          Active leak - minor (up to a 1-2 gallons per 24 hour day
Needs paint
Also thought hydrant codes that were really lat/lon could be very helpful at coordinating "massive" emergent services, such as food/medicine drops after an emergency that blocks roads. Having a national/international system would be ideal.


On 5/3/2016 5:10 PM, Scott Warner wrote:
Does anyone have any ideas or ways that they have numbered their fire hydrants countywide that would make sense to the fire fighters that inspect and use them as well as make sense to a person that looks at it on a map?  We've talked about doing a grid but nothing seems to make sense when brainstorming this idea.

We want to leave room for growth but yet consider cities and hope they buy in to a countywide numbering system.

Thank you,
Scott Warner, GISP, FPEM
Public Safety GIS/ 9-1-1 Specialist/WebEOC Administrator/
Special Needs Registry Technical Specialist
Bay County, Florida Emergency Services
700 Highway 2300
Panama City, FL 32409-5090
Main:    (850) 248-6040
Direct:  (850) 248-6041
Fax:       (850) 248-6059
LAT:  30.2990648    LONG:  -85.6622406
USNG:  16RFU2864152683

Past President- Florida Chapter of URISA
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