1945 CORREGIDOR "JUMP MAP" - This is a faithful DIGITAL reproduction of the
map prepared by 670 Engineer Topographical Company under the direction of
the Chief Engineer, Sixth U.S. Army in February 1945. The original map
was compiled from large scale aerial photographs taken on Mission 5M-9-Z-1
JAN. 1945. It is professionally redrawn
as a single *.pdf sheet by our Mapmaster, Martyn Keen.
The map was issued to officers of the ROCK FORCE and was the
only large scale map made available to them for the Corregidor Operation.
In a decision of almost unparalleled stupidity, the Army considered that the
accurate pre-war maps, being still classified as SECRET, should not be
made available to the men who would be sent there to join battle. This
notwithstanding that the Japanese could safely be assumed to be fully
familiar with the topography of their own island!
This single sheet map can be printed to any size. For
best results, we recommend printing on a plan plotter at 1:12,500 on an A1
sized (841mm x 594) sheet of paper. It also prints quite well on an A3 sheet
size. On an A0 sheet (1189 X 900) print to maximum scale of 1:6000.
via e-mail will be as a *pdf file with your surname as password.
Printing is best
accomplished using a drafting plotter, however to print a section of
interest on an A3 printer, zoom into the required area and print with the
"Page scaling" set to NONE. The whole file can also be printed on a number
of A3 sheets using the TILE ALL PAGES setting. Normal printing of
reduced images can be accomplished on ANY printer using Adobe PDF settings.
The map is redrawn as printed, not as issued - it does not contain the
hand-drawn disposition and strafing-line markings. It contains copyright
data and Heritage Bn markings not originally printed. The *.pdf file is edit
We are not making
purchase of the map automatic yet (because I have forgotten how,
and need professional help, remember?) So, until we can work it all out, click
on the e-mail address below and you'll be taken to the secure Paypal
site. The donation for this map ITEM#JUMP-01 is $20. Your surname will be
the password for the file which will be e-mailed to you.
JUMP MAP COORDINATES
At RockForce.org, I have been
going through the S-3 reports and notice that
coordinates 32.7-40.7 are for the Ice Plant.
Numerous other coordinates are also listed but
not near any structure to use as a reference.
Would anyone know how to correlate this style of
military coordinates to their specific location
on this map? What map has this type of grids?
The coordinates you are looking at were used on
the 1945 Jump Map, which the 503d PRCT used on
Corregidor. The Philippine Polyconic Grid (PPG)
was placed, as a reference, on these maps. The
paratroopers used the grid on the map during the
battle and after to illustrate their reports.
The PPG was based on a projection of the curved
surface of the Philippines, projected as a
conical shape - hence the name. The grid on the
Jump Map is in thousands of yards and is a
measure of yards East and North of the datum.
The grid was notated along the western (left)
and southern (bottom) edges of the Jump Map.
The coordinates you gave for the ICE Plant at
32.7 - 40.7 is an abbreviation of the PPG
coordinates. The unabbreviated PPG coordinates
would be 832,700 yards East, 1,740,700 yards
North. On the Jump Map the last three digits
Using this coordinate system on Corregidor, the
first numbers were usually omitted (that is the
8 and the 17). These latter portions of the
coordinates were unnecessary as they refer to 8
hundred thousand and 17 hundred thousand yards
East and North respectively.
For the last three digits of the coordinates the
paratroopers would have used a 12,500 Scale with
their Jump Map measuring from the nearest grid
line to the west and south. These measured
distances were all less that 1,000 yards and
were added to the abbreviated coordinates as a
decimal of 1,000 yards.
Above is a copy of a portion of the digital Jump
Map of the area of Engineers Ravine. I have
marked the coordinates of the PPG along the
western and southern portion of the grid. It can
be seen the Ice Plant lies between 832 and
833yards East; and 1740 and
North. The Ice House, marked as a hatched
rectangle, is approximately 700 yards east from
the 32 grid
line. Therefore, the coordinate would be 832 plus
700 yards or 832.700 (as
the paratrooper recorded them) or 832,700 yards
East. Similarly, the Ice Plant is approximately
700 yards north from the 40 grid
line. Therefore, the coordinate would be 1740 plus
700 yards or 1740.700 (as
the paratrooper recorded them) or 1,740,700
yards North. I've marked the example coordinates
You will see on the Jump Map that the Ice House
is marked on the eastern side of Engineers
Ravine. The area is also marked as destroyed on
the original Jump Map. This was an error on the
part of the original aerial photographic
interpretation. The Jump Map was known to
contain inaccuracies. This was because the
original prewar Corregidor Maps were not
released to the Jump Map cartographers.
I've also noticed in some published reports that
coordinates were often written with the decimal
point in the wrong place, but it is easy enough
to correct by looking at the first two whole
numbers at the start of the coordinate.