coordinates format to GPS

Question

I was wondering if someone could help me figure out how to go about converting the coordinates on a map I was sent from abroad from the format I see to the usual latitude/longitude I'm used to. (I'm not a matemathician, just trying to give my parents a hand plotting this on Google Earth). What is throwing me off is I see East (este) and North (norte) on the map, but the location of this place is in Peru. Any thoughts will be much appreciated!

What I was sent is in the image.Cartographic information

Answer 1

What I did: Peru is close to the equator, hence angular distances are roughly proportional to horizontal distances, both north-south and east-west. The numbers in the Distance column are close enough to what one computes from the East and North column differences using Pythagoras. This suggests that the two coordinates are just measured in the same units as the distance, from some starting point.

As 8.6 million is quite large and at the same time somewhat close to the ten million meters of a meridian length (actually, that was the original definition of "meter"), I suspect that the unit is "meters" and that North is just the number of meters north of the South Pole (with an extraordinary sub-millimeter precision). That would make a North entry of $y\,(<10^7)$ correspond to approximately $90-\frac{9y}{1000000} $ degrees south. So I suspect that $A$ is at 12°25.38' S, approximately.

But what would then be the reference point for the East column? What interesting point or meridian is about 312 km (about 3°) west of your region of interest? Possibly the 80° W meridian?

Answer 2

The last two columns are probably UTM coordinates in meters.

South of the Equator, the "northing" coordinates are measured from an imagined line 10,000 km south of the equators, so with the values of around 8,619 km this would correspond to a latitude of about 12° S, which matches Lima.

In order to interpret the "easting" coordinates you need to know which UTM "zone" the coordinates are from, but it's probably zone 18 South, which roughly seems to seems to match Lima too.

This should be enough for you to type the values into an UTM converter (which I'm sure can be found somewhere on the web given a little googling, e.g. http://users.tpg.com.au/adslly6v/UtmGoogleStreetView.html).

[Also, giving the coordinates to a precision of tenths of millimeters is almost certainly overkill. For plotting on a map you can safely ignore the decimals.]