1940 - 1990
Coast and Geodetic Survey (Retired)
12934 Desert Glen Drive
Sun City West, AZ 85375-4825
whimsical, yet serious look at the events, technology advances
and people of the past 50 years in geodetic surveying as
seen through the eyes of one who traveled the road, all
the way. The period is divided into three segments: Dawn
of a New Era 1940 - 1950; Break with the Past 1950 - 1970,
and New Age of Geodesy Begins 1970 - 1990. Each contains
synopses of major happenings, anecdotes of the time and
names of some of the people directly involved in the events.
(C&GS) and (NOAA) following names indicate the persons
were members of the commission officer corps.
OF A NEW ERA 1940 - 1950
most progressive and productive era in American geodesy began
innocuously enough, continuing much as it had in the 1930's
and earlier decades. Coast and Geodetic Survey (C&GS) triangulation
and leveling parties roamed the land establishing geodetic control,
while a small office force processed the data for publication.
This is how it had been for more than 100 years. There would
be many changes in the next five decades.
Time Field Parties
surprisingly, field parties were to see the first of the
changes. In the past, most personnel were hired for the
length of the project and once the job was finished they
were paid off and advised where and when another project
was to begin. It was up to each to travel to the new location
at their own expense. This practice changed in the 1930's
and field parties became more permanent units, working the
cooler climes in summer and the southern states in winter.
arrangements made it conducive for party members to bring their
families with them, living in privately owned house trailers
in a self contained environment, usually in town parks, fairgrounds
and the like. The all male tent encampments of the past, with
their mess facilities, which contributed so much to the legends
of field life disappeared, except for some mountain work and
Alaska assignments. Field parties operated in this fashion for
about 30 years before economic and other conditions made it
impractical to continue that way of life.
Computers Draw C&GS Interest
occurring at Iowa State University, Ames, IA, in the late
1930's and the University of Pennsylvania in the early 1940s
would effect nearly everyone in the world in the ensuing
decades. These events led to the construction of the first
automatic electronic digital computer (EDC), the Atanasoff-Berry
Computer (ABC) by John V. Atanasoff and Clifford Berry in
1946, J. Presper Eckert and John W. Mauchly under U.S. Army
sponsorship, developed the mammoth Electronic Numerical
Integrator and Computer (ENIAC) at the University of Pennsylvania.
From this and other beginning efforts, John von Neumann
developed the storedprogram EDC in the 1950's, the forerunner
of present day equipment. The C&GS with its ever increasing
volume of computations had a standing interest in anything
new that might ease the burden and the developments didn't
go unnoticed. Accordingly, early in 1942, Lansing G. Simmons,
Chief, Philadelphia Computing Office made a visit to the
University of Pennsylvania and found that the machine was
still in a primitive stage and could not, for example, multiply
positive and negative numbers and sum the results, an integral
part of the adjustment process and geodetic computations
in general. Nonetheless, he and others in the Geodesy Division
were convinced that such machines would be the wave of the
future, yet recognized it would be a decade or more before
they would become available. In the interim period, high
speed automatic computers were employed to ease the work
Used For Least-Squares Adjustment
1946, Charles A. Whitten made the first least-squares adjustment
of triangulation using Bureau of the Census automatic, high-speed
data processors. These International Business Machines (IBM)
processors utilized punch cards in the calculations. The
earlier computer developments had no direct bearing on this
geodetic computation breakthrough, nevertheless the fact
that the technology was on the horizon, was a contributing
1948, the C&GS installed similar automatic computers
(ADPs) and began the process of adapting them to geodetic
computations. The ADPs were first employed to form and solve
normal equations by the Doolittle method, up to and including
the computation of the residuals stage. It wasn't that they
could do the job faster, but more importantly that they
could be run 24 hours a day, at a modest additional cost.
could solve about 15 equations in each 8 hour shift, and
that was the solution rate most mathematicians (later changed
to geodesist), in the Triangulation Branch, achieved in
the same period. However, a few in the Branch developed
superior speed and accuracy in operating rotary calculators,
using a feel and sound system, rarely, if ever, viewing
the keyboard or dials before completing a series of multiplications.
This small group averaged 20 or more equations solved per
end was drawing near for mechanical calculators, albeit
it would be 20 years or more, before they were gone from
most desks. More important to many involved in solving large
sets of normal equations on such machines, was the fact
that the drudgery of that job would soon be just a memory.
War II Intervenes
World War II, regular geodetic activities were suspended
for the most part and much of the effort was directed to
carrying out needed surveys at defense facilities in the
U.S. and Caribbean area. Field parties operated at reduced
strength or were disbanded and the office staff also was
reduced as members of both groups entered the military.
The major field work, accomplished in this period, was measuring
an arc of first-order triangulation from Skagway in southeast
Alaska, over White Pass to Whitehorse in the Yukon Territory
of Canada, then following the Alcan Highway road builders
north westward to Fairbanks, a distance of about 575 miles.
the end of the war, with the connection to the lower 48
triangulation observed, plans were made to complete the
primary horizontal control in Alaska and to tie the several
local astronomic datums to the North American datum of 1927
(NAD27). This was a wise decision, considering that the
Cold War got colder and oil was found on the North Slope
parties were in the field each working season and most of
the work was done by 1956. Despite the hardships and danger,
Alaska was considered a plum assignment and the per diem
was higher too. The versatility of Bilby towers and the
ingenuity of the men who built them was demonstrated time
and again in Alaska.
to National Topographic Mapping Program
last of the great arcs had been observed in the early 1930's,
from Providence, RI to Key West, FL, following the Atlantic
coast, a distance of about 1,600 miles. During the big push
to complete the first-order network in that decade, which
was funded by civil works programs, most were arc surveys.
However, late in the decade the program to begin filling
in the areas between the arcs was instituted. The program
continued in the pre-and post-war years and into the following
of the work was done in support of the U.S. Geological Survey's
(USGS) nationwide topographic mapping program, involving
control for a few quads here and a few quads there. This
piecemeal approach was dictated by funding and other requirements.
There was one exception, the USGS reached an agreement with
the Commonwealth of Kentucky to accelerate the program there.
To support that goal, the triangulation was completed, but
for two small areas, by about 1950.
the area work was classified as second-order (the then 1:10,000
standard), the observations were made to first-order specifications,
with minor exceptions. New standards and specifications
were drawn up in 1957, which took these exceptions into
account, so that all area nets could be classified to the
same order of accuracy.
Offices and SPCS
offices were setup in New York City and Philadelphia to
aid in adjusting the numerous new surveys made in the 1930's.
Among the assignments, was the conversion of the published
stations' latitudes and longitudes to plane coordinates
on the recently created State Plane Coordinate System(SPCS).
Early on, it was necessary to compute the required tables,
field offices were sponsored by the C&GS and funded
by various civil works agencies. The NY Computing Office
was in existence between 1932 - 1964 and the Philadelphia
Office from 1940 - 1943. Both offices were placed under
the Civil Service system about 1942. And, both contributed
significantly to reducing the large backlog of work.
SPC's was a huge task, even after tables had been prepared.
Originally both systems, Lambert and transverse Mercator,
involved a combination of logarithms and natural functions
and each computation was made in duplicate as a check. Tables
for inverse computations were not available until the late
1940's. An addition check was made by computing selected
grid distances between all points, converting these distances
to geodetic values via scale factors and comparing them
with the published results.
at the beginning, Lambert plane coordinates could be computed
using natural functions, provided a 10-bank calculator was available,
and few were in the 1930's and early 1940's. In the late 1930's
Lansing G. Simmons, then in charge of the Georgia Geodetic Survey,
developed tables based on empirical formulas to compute transverse
Mercator coordinates using natural functions. The computation
time was cut in half.
of Logarithms Near End
geodetic computations were made using logarithms, including
the preparation of side and length equations, computation
of triangle sides and geographic positions. The latter was
a formidable chore, requiring 135 entries for longer lines.
It was once estimated that the computation used up one mile
of lead pencil. Others thought 0.5 mile was closer to the
1941 Lansing G. Simmons, then in charge of the Philadelphia
Computing Office, conceived position computation formulas,
based in theory on the transverse Mercator projection, that
was amenable to natural functions. Tables were prepared
covering only the conterminous States (latitudes 24-50)
and were in feet, with the idea that some surveyors and
engineers would use geographic coordinates. It didn't happen.
in 1944 tables were prepared in meters, extending from the
equator to 75. In conjunction with the conversion, natural
function tables for sines and cosines, at 1" intervals,
were computed in the same office. The resulting Special
Publication (No 231) soon became a best seller.
Universal Transverse Mercator (UTM) grid, a world wide plane
coordinate system was developed in the 1940's by the Corps of
Engineers, U.S. Army, following the recommendations of Oscar
S. Adams of the C&GS Geodesy Division. The grid consists
of bands, 6 of longitude wide, and a maximum scale reduction
of 1:2,500. Original tables (for the Clarke spheroid of 1866)
were computed by a Civil Works project, in NYC, sponsored by
the U.S. Lake Survey (USLS) during the early 40's. The USLS
unit evolved into the Geodetic Division of the Army Map Service
(AMS) about 1943. Later, tables were computed for other ellipsoids
then in use. Floyd W. Hough, David Mills, Homer Fuller and Frank
L. Culley were directly associated with the grid's development.
War II Technology Advances Surveying
developed during World War II began almost immediately to
find places in surveying. Shoran, a special type of radar,
was used to control hydrographic surveys in 1945. In 1946,
Carl I. Aslakson (C&GS) examined its possible use in
locating islands, atolls and the like, that were beyond
visual means to geodetic accuracy. In 1951 the method was
employed, with the longer range C&GS developed Electronic
Position Indicator (EPI), to position 4 islands off Alaska
in the Bering Sea.
the early 1950's, the U.S. Air Force measured a Shoran trilateration
net between Florida and Puerto Rico, continuing on to Trinidad
and South America. A similar net connecting North America
and Europe via Greenland, Iceland, Scotland and Norway was
observed between 1953-1956 by the same organization.
1948 a novel survey procedure, flare triangulation, was used
to connect the Florida mainland with the Bahamas. Flare triangulation
involves simultaneous observations from at least 3 ground stations,
on each land form, to a flare dropped at a prescribed location
by a high flying aircraft. It was first used in 1945 to connect
the triangulation of Denmark and Norway across the 90 mile span
of the Skagerrak. While the experiment was viewed as a success
there were too many problems, including the need for near
perfect weather conditions, for the method to be generally accepted.
Bergstrand's experiments, in Sweden, to employ light to measure
distances came to fruition about 1948. This event was to have
the same dramatic impact on geodetic surveying as did Jesse
Ramsden's direction theodolite, reading to 1", in 1787. This
instrument, named the Geodimeter, would reduce the time required
to measure base lines from weeks to hours, without any reduction
in the accuracy of the line. Furthermore, it permitted the measurement
of regular length triangulation lines, doing away with the costly
and accuracy lessening expansion nets.
very eventful decade thus ended, holding great promises for
WITH THE PAST 1950 - 1970
golden age of geodetic field operations in the U.S. began
shortly after the war ended in 1945 and reached its zenith
in the late 1960's. It began to fade in the early 1970's
as governmental reorganizations and other factors, including
economic conditions, directed funding priorities elsewhere.
Despite these annoyances, even a name change, after more
than 160 years the quality of the work was not effected.
If anything it became better, albeit the productive rate
about 20 years, numerous parties were in the field carrying
out mostly triangulation and leveling with smaller units
doing triangulation reconnaissance, astronomic and gravity
work. Sub units were assigned to various space and DoD facilities
including Cape Canaveral, Vandenberg AFB, Pt. Mugu and White
optimum steel tower party had 3 observing units and about 40
personnel, similar mountain parties about 30 people.
T-3's Replaces Parkhursts
T-3 theodolites replaced the Parkhurst, which had been in
service for about 25 years, in 1952. Early fears that these
small optical reading theodolites were unstable proved unfounded.
Some observers found the T-3's stubby gun-sight pointers
inadequate for night work and to resolve the problem taped
beer can/bottle openers to the top and bottom of the telescopes.
Fortunately, this piece of equipment was never in short
supply on parties. Later illuminated finders, similar to
those found on Parkhursts, were added.
details aside, economic benefits were accrued by replacing Parkhursts
with T-3's. For the most efficient operation the Parkhurst required
a 3 person observing unit, an observer, recorder and lightkeeper,
who also read the second (B) micrometer. For T-3's the observer
makes all the readings and on many occasions the lightkeeper
was no longer needed, leaving the slots open for forming more
observing units or showing additional lights.
Equations Replace Condition Equations
the purchase of automatic computing machines in 1948, several
test adjustments were made under the overall direction of
Charles A. Whitten, Chief, Triangulation Branch, to evaluate
the method of observation equations (a k a method of variation
of coordinates), both on the ellipsoid and the plane. By
1953, most large and many smaller networks were being adjusted
using observation equations and few people had any doubt
that the long reign of condition equations was about over.
was obvious from the beginning that the method lent itself
extremely well to automatic computers because the formation
of the equations follow identical routines for each specific
type of observation, i.e. direction/angle, distance and
azimuth. There is no need to study the network to determine
the number and kind of condition equations, nor to form
them, difficult tasks at anytime. Observation equations
require only the identification of the observations and
assumed positions be computer recognizable, and similarly
for the fixed positions, weights and any conditions placed
on the observations.
late in the 1960's, it also was necessary to select the
normal equations' solution order to minimize the computer
space used. After 1970 this was done internally.
1957, with the purchase of an IBM 650 electronic computer
the method of observation equations officially replaced
the method of condition equations, which had been employed
for more than 100 years, although the method would continue
in use for another 10 years or so. By then, retirement and
other forms of attrition had decimated the ranks of those
who fully understood condition equations. And, the new generation
of geodesists had, at best, only a superficial interest
in the method.
the same time frame, the Cholesky method for solving normal
equations was introduced, its fewer steps making it ideal
for use with computers. It had not been employed much previously
because the fewer steps required didn't translate into significant
savings in time and effort for hand computations when compared
with the Gauss-Doolittle procedure used since 1878. Furthermore,
Cholesky involved square roots that were not easily attained
with mechanical calculators then employed. Gauss-Doolittle
continued to be used for hand computations and remains a
viable method for such calculations.
capacity was limited and only the primary scheme was adjusted
simultaneously. Supplemental stations, many positioned by
single closed triangles, intersection points and other small
jobs were often adjusted by hand, using condition equations.
1962, an IBM 1620 electronic computer, with a larger capacity
and faster became the work horse of the bureau for a decade
before being replaced by a still larger and faster computer.
As computer capacity improved, the supplemental and intersection
points were adjusted in separate computations and eventually
entire networks were adjusted in single weighted computations.
Adjustment Theory Becomes Rule
in the change over period, base lines and Laplace azimuths
were held fixed in accordance with long practice and considered
opinion that these observations were far more accurate than
the angle measurements. However, this rationale changed
within a few years, as modern adjustment theory that all
observations should receive corrections was accepted. By
1965, accuracy estimates were routinely computed as well.
Neither practice was really meaningful, because most of
the adjustments of the time were badly constrained. From
the beginning, accuracy estimates were expressed in terms
of probable error and the practice continued until about
1970 when the standard error concept, conforming to modern
error theory was adopted.
sheets containing all information, other than descriptions,
were computer generated by the early 1970's.
A. Whitten - Geodesist
A. Whitten, far more than anyone, brought geodetic computations
into the computer age. His successes with punched card computations
(1948-57) provided the catalyst and know how needed to adapt
the early electronic computers for similar computations.
His leadership and interests in adapting the ever improving
computers to geodetic needs didn't end with his retirement
in 1972. He was often consulted for his expertise in a wide
range of geodetic matters as well, continuing to make significant
contributions for the next 20 years.
was a man of many talents, a superb all around geodesist
who for more than 40 years served in a variety of positions
including Chief of an astronomic party, Chief, Triangulation
Branch and Chief Geodesist. A strong advocate for utilizing
geodetic surveys to measure crustal motion, Whitten published
numerous papers on the results and was convinced such data
would one day contribute to the prediction of seismic events.
was recognized internationally for his work in adjusting the
triangulation of western Europe, the basis for the European
Datum 1950 and was President, International Association of Geodesy
(IAG) 1960-63. Charles A. Whitten died in 1994, at age 84.
C&GS obtained its first electronic distance measuring
instrument (EDMI) a Model 1 Geodimeter in 1953, and the
second a Model 2 Geodimeter in 1956. In the period 1953
- 1958, 84 triangulation lines were measured, the first
between stations KILIAN and THERESA in eastern Wisconsin,
a distance of about 2.25 miles. Four previously taped base
lines were included in the total. Each line was observed
on at least two separate nights, except for 4 lines in Arizona
where only one measurement was made. A measurement consisted
of 6 observations, spread over 75 - 90 minutes. The longest
line observed was 26 miles, the shortest 0.7 mile and the
average 10 miles. All new lines were satisfactorily included
in the adjustments of the triangulation.
models weighted in excess of 300 lbs. and while good results
were obtained from 12 ft. wooden towers, those from a 103
ft. Bilby tower were not, primarily because of stability
problems. The problem was resolved in short order. C&GS
field personnel were highly skilled in adapting equipment
to fit any need, and this situation was no exception.
a result of these tests, a first-order base line was specified
as resulting from 12 complete observations, 6 on one night
and 6 on the second.
most obvious conclusion drawn was the 140 year period of measuring
base lines with various mechanical apparatus had ended. Accordingly,
the last regular taped base line was measured near Salmon, ID
in 1958. Base lines specifically measured to test EDMI were
taped at Beltsille, MD in 1964 and near Culpeper, VA (MITCHELL
Base) in 1965, with a highly accurate remeasurement in 1967.
The first was slightly more than a mile in length, the second
about 5.6 miles.
Give Longer Range
model Geodimeters were considerably lighter than early versions
and weight was no longer a bother, however longer range,
especially in daylight and haze was desired. To achieve
this, George B. Lesley modified a Model 4D Geodimeter with
a 2 milliwatt laser as the light source in 1965. Tests showed
conclusively that the desired results were obtained. Ten
mile lines were easily measured in bright daylight and at
night, a stronger light return at all times. Furthermore,
successful measurements under adverse weather conditions
were the rule. On the basis of these tests, AGA (Geodimeter
Co.) was contracted to convert about 15 Model 4D Geodimeters,
then in use in the U.S., to laser instruments.
the 1970's, Lesley replaced the 2 milliwatt laser in an instrument
with a 10 milliwatt one. This extensively modified Model 4D,
known as Big Red, routinely measured distances in excess of
50 miles in daylight. AGA and other firms produced laser instruments
in the late 1960's.
and Other Microwaves
using microwave as a measuring source appeared on the scene
about 1957. Tellurometer was the first, developed by T.L.
Wadley of the South African Research Council. They were
lightweight, operated in daylight, had long range capability
and less expensive than electro-optical instruments, good
features that attracted many surveyors. However, the observations
were seriously effected by humidity, especially on longer
lines and by a condition known as ground swing. The latter
could be corrected by taking certain steps, but was not
the interstate highway program many surveys, including most
by the C&GS, were microwave measured traverses and could
only be classified as second-order class II (1:20,000) for
this reason. Had electro-optical instruments been employed,
these surveys would have rated at the very least, the next
higher accuracy class.
Top of Page -