SA Country Fire Service (CFS) - Geographic Coordinate Converter

You can convert between geographic coordinates and Universal Transverse Mercator (UTM) coordinates using this form. You will find usage instructions below the map - scroll down.

Geographic (deg) (decimal) or (ddd mmm ss)	Map Coordinates (UTM)		SA CFS Map Book
lon	x (easting)	meters (six digits)
lat	y (northing)	meters (seven digits)	map ref:	(six digits)
	zone		map num:
	hemisphere N S

Geographic coordinates displayed in decimal degrees. Negative numbers indicate West longitudes and South latitudes. UTM coordinates are entered and displayed in meters. The ellipsoid model used for computations is WGS84.

General Use

You can move the pointer on the map to change the lat/lon in the entry form.
At any time you can press the '>>' button in the To/From column to convert the displayed lat/lon to UTM coordinates.
At any time you can press the '<<' button in the To/From column to convert the current dispalyed UTM coordinates to lat/lon.

When entering CFS Map Book coordinates into the SA CFS Map Book Input section of the form, using map number (ignoring any letters) and map reference coordinates:

Compute the UTM Zone directly from the map number by pressing the '<<' to the left of the map number you have entered.
Compute the UTM Easting and Northings by pressing the '<<' to the left of the map reference you have entered.

The Peak Finder button can be used to see terrain features near the point displayed on the map.

How to use the 'SA CFS Map Book' Input

The CFS Map Book states that the preferred method of giving reference is by region, map number, followed by the relevant six figure coordinate or map reference, i.e. Kangaroo Island, Map 74, 897467.

The six figure map reference is obtained by:

first determining the first three digits along the top of the map, that is by the two digits directly indicated, and the third digit estimated by interpolation.
then determining the second three digits from the side of the map, that is by the two digits directly indicated, and the third digit estimated by interpolation.

Let's try to determine the map reference for "1.5km North of Middle River Dam, Strepera Waterfall, Kangaroo Island" . This has a map reference of 897467 on map 74 of the Kangaroo Island map series.

Go to map 74.
The eastings are the grid numbers along the top of the map. You would read "89" directly, and then interpolate, "7".
The northings are the grid numbers along the side of the map. You would read the "46" directly and interpolate the "7".
This makes a resultant map reference of "89.7 46.7" -> "897467".
Together with the map number "74", you should be able to determine the UTM Zone Number, "53", and the easting "689700" and northing "6046700" using the tool above.
These three coordinates further translate to a longitude, "138.6218" and latitude "-34.9215".

Another example you can try yourself.

On Map 163 of the Eyre Peninsula map book, locate Point Warna near the northern part of the coast (near Louth Bay).
Did you get 85.8 and 77.5?
That is 858775
Now convert to eastings/northings, 585800, 6177500. (Hint: Enter the reference '858775' and then the map number '163' and press the '<<' button to the left of the reference.)
and finally to lon/lat, 135.93505/-34.54063. (Hint: just click on the '<<' button to the left of the easting/northings.)
Hopefully the Map Inset shows the correct location as well.

The UTMcoordinate conversion part of this program is based on code written by Charles L. Taylor. The original site is no longer available, but a licensed Python version is here.
The SA CFS conversion parameters, painfully extracted, map by map, from the CFS Map Books by Hank de Wit.