PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
April 2020
211
Hans J. Wehrli passed away on
February 20, 2020. He is survived
by his wife of 64 years, Lisette
Wehrli, and his children Nicole
Wampfler, Gregory Wehrli, and
Linette LaMountian, as well as his
seven grandchildren.
Hans, born in Aarau, Switzerland,
on April 25, 1926 came to the
United States in 1953 to expand
Kern Instruments Inc., a subsid-
iary of Kern & Co. AG, Aarau,
Switzerland. Initially the focus of
his assignment was in surveying
instrumentation, including adap-
tation of such instruments for the
optical tooling industry, ranging
in applications from alignment of
paper machines to sophisticated
guidance systems in the aerospace
industry.
By the early 1960’s, under Hans’s
leadership, Kern entered the photogrammetric market and
quickly became an industry leader. Under his guidance in
the concept, design and sales are instruments such as the
PG2, AT Table, Monocomparator, Point marker, Stereo com-
parator, DSR analytical stereoplotter, and several one-off
instruments.
Hans understood early the benefit of electronics to improve
productivity.
For example, the DKM2-A, a universal one-second theodo-
lite became the standard for a new generation of optical/me-
chanical theodolites with automatic vertical indexing. And
when combined with an electronic distance meter, displayed
the distance in digital format. In addition to surveying uses,
the next generation of this new theodolite found wide accep-
tance for highly precise industrial measurements.
Hans was instrumental in 1969 in having Kern optical lens-
es accompany the moon landing of Apollo 11 where these
lenses were used in the craft’s acquisition cameras which
filmed the tests of reactions of men and materials in space.
In Memoriam
Hans J. Wehrli
Photogrammetric Pioneer
As a visionary, Hans very quickly
recognized the power and validity
of PC’s. As the leader, he dedicated
his time and efforts to a team that
would convert the entire software
suite to this new DOS platform.
Hans and his Kern team brought
the first Industrial Measurement
System when it released the ECDS
(Electronic coordinate Determi-
nation System) integrating an E2
theodolite with a PC and software
providing three essential compo-
nents: data collection, data reduc-
tion and data analysis. This system
was used for the alignment of the
magnets of the SLC (Stanford Lin-
ear Collider).
In 1988, Hans received the ASPRS
Fairchild Award established to rec-
ognize someone who demonstrated
outstanding efforts and influence in
the development of the art of aerial photogrammetry in the
United States.
Even after retiring in 1988 when Kern was merged with
Wild Leitz (Hexagon), Hans continued to influence the
photogrammetric market. He designed and implemented
the low-cost Alpha 2000 (analytical stereo plotter), RM-1 to
RM-6 photoscanners and DAS digital aerial cameras under
the company Wehrli & Associates.
Kern25YearsUSAAnniversary, May24th, 1979
