J. B. THEIS
Bausch G Lomb Incorporated
Rockville, MD 20851
Transferring Today's Changes
onto Yesterday's Maps*
The Zoom Transfer Scope (ZTS)f is a change detection and
transfer instrument that will take virtually any visual input,
compensate for its distortions, and superimpose it on a map
or other reference.
T
simple, yet efficient,
instrument to update maps has existed
for decades. The advent of the space age,
and the resulting information deluge, added
the impetus to satisfy this need. That is, an
instrument that could take the varied photographic outputs of an airborne or space
vehicle (conventional "aerial" photography,
multispectral, television, radar, . . .), comH E N E E D FOR A
retrieval and reduction in diverse disciplines around the world. This paper describes the ZTS instrument system, summarizes several experiences, and mentions
some experimental work that indicates future directions in change detection and
transfer activities.
Soon after the introduction of the first
The Bausch G Lomb Zoom Transfer Scope (ZTS) graphABSTRACT:
ical data transfer system instantly shows the scientist what's new
and allows him either to graphically record the changes or to
photograph them for later detailed study or permanent record. The
system will take virtually any visual image as input and will
optically adjust it to fit the reference material, e.g., a published
map. A number of resourceful users with unique requirements
have devised modifications and interfacings with other equipment.
Selected examples include the fields of meteorology, geography,
geology, forestry, transportation, archaeology, engineering, agriculture, material testing, fishing forecasting, and map editing.
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commercial model, a special Zoom Transfer
Scope instrument, ZT9, was built in response to the U. S. Army Engineer Topographic Laboratory's (USAETL) "Technical
Characteristics for Contour-Planimetric
Compiler." These Technical Characteristics
and the ensuing acceptance and engineer
design tests and evaluation of the instrument are described in the 1972 ETL report,
Zoom Transfer S ~ o p e . ~
Some potential users of the Zoom Trans* Presented itthe ASP/ACSM Fall Convention, fer
instrument seem
be hesitant
to consider using an instrument which is
Little Rock, Arkansas, October 20, 1977.
t Zoom Transfer Scope and ZTS are trademarks portable and costs little more than a mediumof Bausch & Lomb Incorporated for graphical priced car-an instrument, which, in some
data transfer instruments.
models, can be folded into a case the size
pensate for the various inherent distortions,
and fit the newly acquired data to a reference system, e.g., a map. For, unless tied to
the real world of exact location and dimension, the new information would be of little
use.
Unveiled at the 1971 Fall ASPIACSM
Meeting in San Francisco,' the Bausch &
Lomb Zoom Transfer Scope instrument is
already the key to successful information
PHOTOGRAMMETRIC
ENGINEERING
A N D REMOTE
SENSING,
"01. 45, No. 3, March 1979, pp. 309-316.
309
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1979
of a piece of hand luggage. This hesitation to rapidly producing accurate vegetation1
seems compounded when they see other terrain resource type and land use maps . . ."
Dr. Bryce L. Shrock,Womputer Sciences
change detection and recording systems
which involve a large room full of expen- Laboratory, U. S. Army Engineer Toposive computer, and supporting, equipment. graphic Laboratories, Fort Belvoir, Virginia,
Such complex and expensive equipment, with no axe to grind save scientific accuhowever, is mainly concerned with the auto- racy, states in the abstract of his paper,
. Digital image processing appears to
matic manipulation and interpretation of
data. If such automation can be afforded offer great promise for the extraction of
(is desirable), the necessary equipment can topographic and intelligence information
easily be interfaced with the Zoom Trans- from multisensor imagery. However, the exfer Scope instrument; but, often, it is not traction process is, in general, a pattern
recognition problem of such complexity that
necessary.
A recent report by the U. S. Army Corps the computer alone is often unable to comof Engineers Coastal Engineering Research pletely solve the problem. Therefore, it
Center (CERC)3 makes it clear that an appears reasonable to combine the superb
agency does not need a money tree to get pattern recognition abilities of the human
into t h e change detection and transfer interpreter with the computational power of
business. In the introduction of their 1976 the digital computer to form an interactive
report, An ERTS-1 Study of Coastal Fea- system. . . ."
These superb pattern recognition abilities
tures on the North Carolina Coast, they
of the human operator are the brains of the
state:
. . . Most of the research on the usefulness ZTS instrument. The ZTS is merely an
of satellite imagery has depended on the accessory to the human brain (a very underuse of highly sophisticated, expensive used organ) and its input sensors, in this
equipment and complex computer analysis case, human eyes.
to derive the significant results published.
One of the intentions of the original
Coastal Engineering Research Center
The company brochuree states:
(CERC)proposal to the National Aeronautics
and Space Administration (NASA) was to
"A modular, tabletop instrument, the Bausch
determine the possible use of satellite imag& Lomb ZTS graphical data transfer instruery in coastal engineering applications with
ment enables the user to view separate
only the aid of conventional photographic
images simultaneously. For example, the
processes and equipment. The results of this
operator may view both an aerial photograph
report should be beneficial to individuals and
and a topographical map of the same area.
small organizations lacking the expertise or
Simplified controls allow the matching of
financial capability to utilize sophisticated
differences in scales and provide other optiequipment and analysis techniques to derive
cal corrections so that the two images appear
useful information from ERTS-1imagery. . . ."
superimposed. Information from the photograph may then be compared to or traced
CERC used photography from the first (30
onto the map. . . ."
July 72) and the last (2 June 73) ERTS-1
missions. A direct comparison of shorelines
With the introduction of the stereo Zoom
between the two films was successfully Transfer Scope instrument at Helsinki in
made using the Zoom Transfer Scope in- July 1976, there are now three major catestrument. This was a people-centered re- gories of the ZTS instrument: (1) the ZT4
search project, using the innate equipment with a 9 x 9 in. vertical input stage (Figfurnished most human beings (eyeslbrains)
with an assist from the ZTS instrument.
Also, a close search of the literature occasionally yields additional gems to buttress
a human's sagging morale. Paul K r ~ m p e , ~
for example, says something nice about
people in his paper, "Using Remotely
Sensed Multiband Infrared Imagery in the
Preparation of Environmental Impact Statements." He states: ". . . Manual interpretation of high altitude infrared imagery by a
professional photo analyst educated in environmental remote sensing and ecology can FIG. 1. ZT-4 with wide base (Bausch & Lomb
be one of the most cost effective means photo).
I'
"
..
TRANSFERRING TODAY'S CHANGES ONTO YESTERDAY'S MAPS
ntal
stage (Bausch & Lomb photo).
ure 1); (2) the ZT4-H with a 20 x 40 in.
transparent, horizontal input stage (Figure 2); and (3) the stereo Zoom Transfer
Scope (Figure 3).
Zoom magnification, continuous to 1 4
with the ZT4 and to 1 6 with
~
the stereo
model, provides rapid, accurate matching of
photo scale to data base scale.
". . . The map (data base) is viewed at lx.
With the photo scale smaller than the map
scale, the operator simply turns the zoom
dial until the photograph is magnified to the
same scale as the map. This feature of positively magnifying the photograph allows the
maximum field of view on the map surface
(7 in. diameter). Also, magnification provides
more useful detail per photo. Therefore,
fewer photos are used.. . .
"If the photo scale is larger than the map
scale, as may be the case with long focal
length photography of low altitude coverage,
optional 2x and 4 x map lenses are available
to replace the standard IX map lens. Also,
for special applications requiring a wider
field of view, an 0.75x map lens is available.. . ."
FIG.3. Stereo Zoom Transfer Scope (Bausch &
Lomb photo).
An anamorphic feature ". . . enables the
instrument to compensate for geometric
anomalies in a photographic image, for example, due to tilt, relief, earth curvature,
lens distortion, and film shrinkage. Where
such deficiencies are serious enough to
affect the required accuracy, the anamorphic
system provides a simplified correction
capability. It affects only the photo image
viewing optics.
"A product of modern optical science, the
anamorphic system on the ZTS instrument
simply enlarges the image in one direction
only. A dial control selects the direction;
a lever controls t h e enlargement ratio
("stretch") from 1 : l to 2:l. The effect is
to transform the image into one that is more
nearly correct without employing expensive
and complicated photo rectification systems."
A Camera and Adapter system was also
introduced at Helsinki (Figure 4). It can
~be used with either the stereo ZTS (Figure 3) or the ZT4-H (Figure 2). This feature enables the user to make a permanent
record of the change he has detected in his
input (e.g., space photography) superimposed on his reference (e.g., a map).
To cover adequately the widespread use
of the Zoom Transfer Scope instrument in
a single paper is impossible. The bibliography provides a general idea. The crosssection of recent applications, discussed in
FIG.4. Camera and adapter system mounted on
the ZT4-H (Bausch & Lomb photo).
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1979
this paper, concerns the fields of geography,
data. Since 1972, the greatest bulk of our
efforts have been directed toward the analysis
geology, forestry, transportation, and coastal
of LANDSAT data. The Zoom Transfer Scope
engineering.
is utilized by our analysts in two separate
Allen Downard7 recently presented a
but closely associated ways.
paper entitled, "How to Deal with a Geo"First, as identified in the text, the analysts
graphic Base System Without a Computer."
use the ZTS to superimpose ground reference
In his abstract, he states, . . . This paper
information on the spectral data. In this way,
deals with manipulating geographic data
he or she can begin to identify the composiwhile it stays in image form. This transfer
tion of the spectral classes. As you well underis usually expensive when done with air
stand, this is a critical step in developing a
reliable classification.
photography and conventional cartography
"The second use occurs after the data has
or through the use of data processing probeen classified. In this situation, the analyst
cedures. The use of a Bausch & Lomb Zoom
relies on his or her ability to interpret the
Transfer Scope (ZTS) graphical data transfer
accuracy
of the classification.An aerial photo,
instrument can reduce the cost, time, and
with the aid of the ZTS, is overlaid on a
energy needed in dealing with geographic
systematic grid of training fields. The fields
data. . . ."
are identified from the photograph and trainLater, while summarizing the advantages
ing field accuracy is then assessed."
of the ZTS instrument, he emphasized that,
The
Mroczynski refers to in his
. . . I t is always on line, never needs a letter is"text"
the
LARS
report, A Forestry Appliprogrammer or systems analyst, and never
gets backed u p in keypunch. T h e ZTS cation Simulation of Man-Machine Techinstrument works best on data that com- niques for Analyzing Remotely Sensed
Data." This simulation, described in detail
puters have difficulty with. . . ."
Another science, which has found great in the report, ". . . uses numerically-oriented
pattern recognition techniques and emphause for the ZTS instrument is geology.
Professor John T. Fisher, University of sizes the man-machine interaction. . . ."
The Zoom Transfer Scope instrument is
Rhode Island, has furnished summaries of
used
at the two points where tieing to the
two challenging projects. The first (Fisher
real
world
of "seeing is believing" is de& Barrett)8 concerns photogeologic cliff
identification and product
erosion mapping. This paper describes a sired-image
editing
(Figure
5).
unique application, as follows, "The anaAn area of daily concern is transportation.
morphic and zoom magnification features of
the Bausch & Lomb Zoom Transfer Scope Preliminary to any planning for improveare being used to compile a geologic map ments, an up-to-date map must be avail~
of the eroding cliffs of Block Island, Rhode able. Eugene C a m p o n e s ~ h i , 'Maryland
Island. The map, at a scale of 1:500 verti- Department of Transportation and Highway
cal, is being compiled from a series of 300 Administration, has recently written that,
offshore photographs in mosaic form of the ". . . the State Highway Administration has
20 km of cliffed shoreline. The anamorphic found the Zoom scope produces satisfactory
"stretch" feature of the Transfer Scope is results when used to update planimetric
used uniquely to produce the necessary features on photogrammetric mapping.
"Where adequate control exists on the
vertical exaggeration for the final geologic
mapping,
we feel that Map Accuracy Stanmap sections, while the variable magnification provides a means of controlling the dards can b e achieved with little diffivariable (between 1:350 and 1:800) scale
of the original photographs. . . ."
The second summary (Fisher & S i m p s ~ n ) ~
concerns the measurement of differential
rates of erosion and accretion.
Forestry is yet another scientific field
which must detect, identify, and position
change. In this case, however, the changes
are often rapid, and hence, a quick, yet
economical, reduction system is desirable.
In a recent letter, Richard Mroczynski,'"
Purdue University, Laboratory for Applica- FIG. 5. Forester comparing classification map
tions of Remote Sensing (LARS), writes:
output with aerial photographs using wide base
"LARS is heavily involved in computer- ZT-4 (Laboratory for Applications of Remote
assisted analysis of multispectral scanner Sensing, Purdue University photo).
"
"
TRANSFERRING TODAY'S CHANGES ONTO YESTERDAY'S MAPS
culty. This has been shown by comparing
updated planimetric features with mapping
produced by stereo plotter. . . ."
And finally, on the subject of coastal
engineering, Dennis BergI3 of the Army's
Coastal Engineering Research Center
writes, ". . . the enclosed material indicates
our use of the ZTS in tracing of dyes injected into ocean waters and recorded on
film, the measurement of shoreline and
bluff recessions in Lake Michigan and
detection of morphological changes of
coastal features as recorded by satellite. . . ."
Mr. Berg included a summary of some
pertinent work by a colleague, Dennis
Prins.I4 Excerpts from Mr. Prins' summary
are as follows: ". . . Coastal research is dependent upon evaluation of such parameters
as currents, waves and along-shore drift or
sediment transport. Since, by nature, the
surf zone is a harsh environment and many
attempts at collecting data in this region
using conventional instruments have met
with failure.
"One method of monitoring surface currents in the coastal zone is to tag the water
mass by using dyes. To record the event,
photographic coverage is utilized and an
accurate record of time is kept with each
photo exposure. . . .
"By using the Zoom Transfer Scope (ZTS),
information is easily transferred from the
photos (of varying size format) to the grid
map of the study area. . . ."
In addition to the wide-spread, multidisciplinary use of the Zoom Transfer Scope
instrument in a straight-forward way, as a
workhorse, imaginative organizations are
using it as a key link to the realization
of other advanced systems. In a previous
paper (1Y76),I5the author mentioned three
such progressive agencies: (1)the Michigan
Department of State Highways and Transportation, (2) the U.S. Army Engineer Topographic Laboratories (ETL), and (3)NASA's
Langley Research Center.
The Michigan Department of State Highways and Transportation has mounted a
ZT-4 on a gantry with free X, Y, and Z
movement, positioned over a Hamilton
drafting table with a two-axis coordinatograph (Figure 6). They planned, also, to
purchase a floating cursor for use with a
digitizer, and, subsequently, use the data
in a digital mapping system.
ETL has recently pioneered in experimenting with using high resolution radar
photography in the ZTS instrument for pla-
FIG.6. ZT-4 mounted on the GuentherIMillard
Suspension System (Michigan Department of
State Highways and Transportation photo).
nimetric map revision. They found the combination acceptable for 1:250,000-scale
work, but needed to do more testing before
coming to any conclusions for larger map
scales.
Then in a happy union of optics and
electronics, ". . . the Zoom Transfer Scope
(ZTS), located at the Langley Research
Center, has been adapted for use with an
International Imaging Systems Additive
Color Viewer. The ZTS superimposes the
viewer image into a map as shown in the
attached photograph (Figure 7) but it can
also be used with the easel portion of the
unit attached."
Mr. Olhorst explained that his work
". . . deals mainly with water phenomena,
with emphasis on pollution detection and
monitoring. I have used the ZTS to superimpose aerial photographs onto USGS maps
with the intent to determine the water depth
at various boat sampling locations."
In the past year, the author has come
across additional experimental work, either
in process or planned for the near future.
Selections from this work fall in the fields
of weather prediction, agriculture, meteorology applied to fishing, and computer
generated map editing. All of this effort
involves the use of satellite materials.
All of man's outdoor activity is dependent
on the weather. Hence, there is a continuous
need for quick and accurate weather forecasting. The author recently visited LaRue
Amacher, imaginative Visual Information
Specialist, National Environmental Satellite
Services (NESS) Applications Group. He
enthusiastically explained a potential. nearreal-time weather analysis system on which
he was working.
PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING,
1979
satellite materials, is the Department of
Agriculture. The Research and Development Branch of their Statistical Reporting
Service has recently purchased a ZT-4-H.
Paul HopkinsI6 has furnished a summary
of his branch's planned use of the instrument.
FIG.7. Wiae oase A -4 adapteu a u l uar; w l u a A'S
Additive Color Viewer (NASA Langley Research
Center photo).
". . .Our research group is presently developing techniques to make use of the Landsat
digital data for crop acreage estimation. . . .
"We felt that the ZTS-4H would greatly
reduce the time and effort required in doing
the two steps of registration. Of particular
importance is its ability to overlay two
sources of disparate scales. Since our present
Landsat grey-scales printouts are of about
1:20 000 scale, we would quite effectively be
able to work with 1:24 000, 1:62 500, and
1:250 000 scale maps.
"Presently, we correct the satellite imagery
to overlay 1:24 000 scale maps. However,
the anamorphic capabilities of the ZTS would
also allow us to use the uncorrected data
tapes quite easily. When larger scale maps
are unavailable, we would also make much
more effective use of the 1:250 000 scale
maps than we presently do.
"We now need to reduce and Xerox the
grey-scales for use with the 1:62 500 scale
maps. The ZTS would eliminate the need
to do this, as well as make a much improved
overlay. Since this map scale is quite commonly the largest available scale, we would
find this ZTS feature to be most helpful in
our work.
"During the field matching stage of registration, the ZTS could shorten the time it
takes to match the photo and grey-scales
printout on a field-by-field basis. . . ."
NESS receives television imagery from
the Synchronous Meteorological Satellite
(SMS) every 23 minutes. Using experimental equipment, eight successive pictures
can be stored on disc. These can be viewed
continuously on a TV screen, thus showing
the cloud formations in motion. This realtime visual information is supplemented by
field weather station data, such as temperature, humidity, barometric pressure, wind
Now for the potential use that millions of
direction, and wind velocity.
fishermen are eagerly awaiting. Don and
What had been missing is a quick, accu- Inez Klopfenstein17 published an article in
rate means of tieing the SMS photos to pre- February 1976, entitled, "Satellite Photos
cise ground locations. Mr. Amacher ex- May Help Fishermen."
plained a potential experimental system to
". . . Fishermen know that fish are most
do this. A viewing screen is interfaced with
abundant where feed is plentiful. In the case
the ZT-4, taking the place of the vertical
of albacore and salmon off the West Continplaten. (This is probably similar to what
ental Shore, the best fishing is found at points
NASAILangley has done.) This input imagwhere upwelling supplies this feed. . . .
ery, on the viewing screen, is superimposed
"Today, environmental satellites from 850
onto a map on the tabletop under the ZT-4.
miles out are transmitting sea surface temperThe adjustment controls of the ZT-4 then
atures to receiving stations on earth . . an
infrared graphic rendition of the earth's suradjust the distorted SMS image to fit the
bce temperature. . . .
map.
"The photographically printed image must
The adjusted image, superimposed on a
be proportionately and very exactingly rereference map, is photographed by a TV
shaped ("stretched") until it fits correctly
camera, through the ZT4's optical system,
onto the flat projection of a mercator chart.
and subsequently displayed on a color TV
With loran lines and bottom contours on the
set. At this viewing station, with live
same chart, superimposed lines representing
weather photos tied to a map, the ground
the thermal fronts become real, obtainable,
weather information can be plugged in.
and desirable locations for which skippers
can set a course. . . .A special complex optical
Another federal agency, working hard to
device called a "transfer scope" is required
fully exploit the wealth of information in
.
TRANSFERRING TODAY'S CHANGES ONTO YESTERDAY'S MAPS
to accomplish the transfer from photo to
chart. . . . Accuracy of actual water temperatures and temperature difference of 0.6 of a
degree centigrade over one kilometer intervals are realized. . . .
"This piece of the space age is ready to
work for fishermen and agencies alike and is
all bought and paid for. A few people (salaries) and some rented telephone copiers can
launch an advanced yet simple data distribution system. . . ."
And, finally, there is increasing use of the
ZTS instrument in a distinct, and very important, category-as a n editing device to
verify the work of other advanced but far
less intuitive systems.
A good example of this is given in a NASA
report published in February 1977,18 entitled, A Procedure used for a Ground Truth
Study of a Land Use M a p of North Alabama
Generated from LANDSAT Data.
T h e authors state that:
needs, a n d h e can often a d d t o i t later.
If there is a need to hook it to a computer,
it can easily b e done. As CERC demonstrated, however, this does not always have
to b e done.
Imaginative users have combined the ZTS
i n s t r u m e n t w i t h a drafting arm, flatbed
digital plotter, light table, gantry-type susp e n s i o n , a n d a c a t h o d e ray t u b e . T h e
anarnorphic stretch has been used to provide
vertical exaggeration.
I n essence, then, t h e Bausch & Lomb
Zoom Transfer Scope instrument is a precision instrument with a change detection
and transfer capability that could be the
answer to rapid and accurate remote sensing
of the Earth's resources.
1. Ambrose, W. and R. Shone, "New Cartographic Techniques with the Zoom Transfer
Scope," presented to the ASP Meeting, San
"The purpose of this study was to formulate
Francisco, California, September 1971.
a method for checking the computer gen2. Brackett, W. Zoom Transfer Scope, Report
erated land use map with a minimum of field
ETL-ETR-72-5, U.S. Army Engineer Topowork, to determine the accuracy of the map,
graphic Laboratories, December 1972.
and to determine if this information can be
3. Miller, G . and D. Berg, An ERTS-1 Study of
used to improve the next generation of a land
Coastal Features on the North Carolina
use map of the area. . . .
Coast, Miscellaneous Report No. 76-2, U.S.
". . . .The computer printout and aerial
Army Engineer Coastal Engineering Rephotographs were compared using a Bausch
search Center, Fort Belvoir, Virginia, January
& Lomb Zoom Transfer Scope. The use of
1976.
this type instrument was necessary for ac4. Krumpe, P., "Using Remotely Sensed Multicurate comparison because the scale of the
band Infrared Imagery in the Preparation of
photographs is 1:20,000, the vertical scale of
Environmental Impact Statements," prethe printout is 1:17,953, and the horizontal
sented to the Workshop for Environmental
scale is 1:22,440. . . .
Applications of Multispectral Imagery, Fort
"The photograph and printout were visuBelvoir, Virginia, November 1975.
ally fitted, using landmarks for reference,
5. Schrock, Dr. B., "Image Analysis: Interactive
and the location of the center pixel was
Digital Image Processing," presented to the
marked on the aerial photograph. This point
Workshop for Environmental Applications of
was used as the center of the study area
Multispectral Imagery, Fort Belvoir, Virginia,
during the field work. The detailed proceNovember 1975.
dures for the ply;ting and fitting are given in
6. Bausch & Lomb Brochure, ZOOM Transfer
Appendix A. . . .
Scope, November 1975.
7. Downard, A., "How to Deal with a Geographic Base System Without a Computer," presented to the Annual Urban and Regional
In summary, the Zoom Transfer Scope is a
Information Systems Association Convention,
change detection and transfer instrument
Atlanta, Georgia, September 1976.
that will take virtually any visual input,
8. Fisher, Dr. J. and J. Barrett, Use of the Zoom
compensate for its distortions, and superTransfer Scope in Photogeologic Cliff Eroimpose it on a map or other reference. I t
sion Mapping, University of Rhode Island,
was developed to assist the computer that
unpublished summary furnished author,
November 1976.
develops, and controls, all other computers9. Fisher, Dr. J. and E. Simpson, Use of the
the human brain.
Zoom Transfer Scope in Measuring DinerenSelected examples have shown the ZTS
tial Rates of Erosion and Accretion along
instrument used in t h e fields of weather
the South Shore of Rhode Island ouer the
forecasting, geography, geology, forestry,
period 1939 through 1975, University of
transportation, coastal engineering, agriculRhode Island, unpublished summary furture, fishing forecasting, and map editing.
nished author, November 1976.
Since the ZTS instrument is modular in 10. Mroczynski, R., Purdue University, Laboratory for Applications of Remote Sensing,
concept, the user buys only what he really
PHOTOCRAMMETRIC ENGINEERING & REMOTE SENSING,
letter to author, November 1976, summarizing use of ZTS in forestry projects.
11. Berkebile, J., J. Russell, and B. Lube, A
Forestry Application Simulation of ManMachine Techniques for Analyzing Remotely
Sensed Data, Information Note 012376,
Laboratory for Applications of Remote Sensing, Purdue University, undated.
12. Camponeschi, E., Maryland Department of
Transportation, letter to author, December
1976, outlining their use of ZTS.
13. Berg, D., Army Coastal Engineering Research
Center, letter to author, November 1976, summarizing ZTS use in coastal engineering
research.
14. Prins, D., Army Coastal Engineering Research Center, enclosure to D. Berg's letter,
summarizing ZTS use in monitoring water
surface currents, November 1976.
15. Theis, J., "The Zoom Transfer Scope-Experiences and Possibilities," presented to the
American Society of Photogrammetry Annual
meeting, Washington, D.C., February 1976.
1979
16. Hopkins, P., U.S. Department of Agriculture,
letter to author, November 1976, summarizing intended use of ZTS in developing techniques to make use of Landsat digital data
for crop acreage estimation.
17. Klopfenstein, D. and I. Klopfenstein, "Satellite Photos May Help Fishermen," The Fishermen's News, February 1976.
18. Downs, Sanford W., Jr., G. C. Sharma, and
Colin Bagwell, A Procedure used for Ground
Truth Study of a Land Use Map of North
Alabama Generated from LANDSAT Data,
NASA TND-8420, Marshall Space Flight
Center, Alabama, 35812, February 1977.
Note: An extensive bibliography is available,
upon request, from the author: Joseph B. Theis,
5731 Crawford Dr., Rockville, MD 20851.
(Received December 20, 1977; revised and accepted December 1, 1978)
Seventh Biennial Workshop
on
Color Aerial Photography
in the
Plant Sciences
University of California at Davis
May 17-19, 1979
T h e Workshop, sponsored by the Forest Service and cosponsored by the American
Society of Photogrammetry, Society of American Foresters, and California Remote Sensing
Council, will feature Vegetation Damage Assessment, Land-Use Planning, Vegetation Mapping, and Related Fields of Agriculture and Resource Management.
For further information contact
William M. Ciesla
USDA Forest Service
Forest Insect and Disease Management
2810 Chiles Road
Davis, CA 95616
Insured Members to Receive a 5O0/0 Credit
on the ASP Life Insurance Plan
Members insured under the ASP Life Insurance Plan will receive a credit on their April
1, 1979 payment notices equal to 50%of the amount they contributed during the policy year
ending September 30, 1978. Credits of this type make the Plan very attractive and it is
hoped that they will continue to b e available in future years. Over the past five years they
have averaged 46%. They cannot, of course, b e promised or guaranteed.
Additional good news is the increased inaxiinuin now available to ASP members. Effective October 1, 1978, a member may purchase up to $108,000 in $12,000 units. T h e maximum amounts for dependent's coverage remain at $35,000 for a spouse and $2,500 for all
children.
All inquiries regarding the ASP Life Insurance Plan or any other plan in the ASP Group
Insurance Program should b e made to the Insurance Administrator, 1707 L Street, N.W.,
Washington, D.C. 20036. Telephone (202) 296-8030.