FREDERICK J. DOYLEU. S. Geological Survey

Reston, VA 22090

Photogrammetry: The Next TwoHundred Years*

WHEN PROFESSOR COLCORD asked me ayear and a half ago to give this talk, he

indicated that he wanted it to be somethingspecial. I gave a lot of thought to how Ishould prepare for it. One of the things I didwas to sign up for a summer course in publicspeaking. We started the first class in the oldGreek tradition with a mouth full of marbles,and at each class we removed one more mar­ble. At the end of the course we could allspeak in clear pear-shaped tones. My con­clusion from that experience was that no oneshould attempt to predict the next twohundred years of photogrammetry unless hehad lost all his marbles. "Looking ahead,"my grandfather used to tell me "is like spit­ting into the wind."

That esteemed founder of our Society, pastPresident, and Honorary Member HeinzGruner has already painted for us the historyof our profession (see pp. 000). We can hopeto continue this splendid development oftheory, instrumentation, techniques, andapplications. We need not necessarily blazenew trials, but rather follow the right onesalready marked for us. And there is ampleallowance for mistakes. Every step of theway need not be perfect; it is the directional­ity which counts. We need to think of changeas paIt of the process of living. We cannotsimply be; we must become.

The second law of prophecy is:"The view of the horizon depends

upon the selection of the vantage point."

ABSTRACT: With the accumulated knowledge of mankind doublingthree times every century, the author attempts td ,predict the situa­tion when photogrammetry capabilities will be 64 times what theyare today. Whether photogrammetry will contribute to a Utopianworld at that time depends upon the doubtful premise that wisdomwill accumulate at the same exponential rate as knowledge.

It is for us astonishing to realize that 90percent of all the scientists who have everlived on Earth are working now (or at leastare being paid to work). And mankind's storeof knowledge is doubling at least three timesa century. So I am asked to tell you what theworld will be like when we know 64 times asmuch as we do now. In order to make someinroads on this formidable task, I have at­tempted to formulate some laws of prophecy.

The ational Archives in Washington isthe depository of much of our nation's ac­cumulated knowledge. Engraved over its en­trance is the first law of prophecy:

"The Past is Prologue."

* Invited paper for the theme session, "TheSpirit of'76," at the Fall Technical Meeting of theAmerican Society of Photogrammetry, Seattle,Washington, September 29, 1976.

Some of us have recently returned from the13th Congress of the International Societyfor Photogrammetry in Helsinki. Remarka­ble there was the introduction of seven newanalytical stereoplotters. We have seenmachines that can automatically producetremendous amounts of digital topographicdata. We have seen contours computer­derived from the digital data that begin toapproach acceptable cartographic quality.We have seen interactive computer­controlled instruments performing many ofthe functions of conventional photointerpre­tation. Quite clearly our view of photogram­metry right now is from near the top of thedigital-computer mountain, and the day maynot be far off when the human photogram­metrist will become merely a standby re­placement for machines.

The third law of prophecy:

PHOTOGRAMMETRIC ENGINEERIN~AND REMOTE SENSING,

Vol. 43, No.5, May 1977, pp. 575-577.

575

576 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING, 1977

"One tends to overestimate short-term gainsand underestimate long-term changes."

I should like to quote for you a paragraph:

"This is a system for acquiring all necessaryterrain information by scanning the groundphotoelectrically, and automatically producinga corrected orthographic photomap. Nophotographic processes are used to acquirethe terrain information. The varying light in­tensities received by the scanning compo­nents are converted to electrical video sig­nals. These signals are immediately stored onmagnetic tape which takes the place of thephotographic film in conventional mapping.The procedures equivalent to orientation,scale adjustment, and relief measurement arecarried out by automatically matching andmodifying the electrical waveforms producedwhen the tape is read out. The proposed sys­tem is designed to print a fully correctedphotomap automatically. The system can alsoproduce a map manuscript with the aid of aphotointerpreter."

This is from an article by Paul Rosenberg inPhotogrammetric Engineering in 1956.

Twenty years later we have the Landsatmultispectral scanner producing astonishingnew looks at our planet. You have heard, andwill hear, more about Landsat than I thinkany good photogrammetrist should believe,but we are still a long way from turning out acompleted map automatically without the in­tervention of a lot of human judgment andmanipulation. Although automatic correla­tion of stereoimages has been with us formore than a decade, it has not yet achievedthe reliability and cost effectiveness to makeit acceptable for routine photogrammetricoperations. The process of compiling con­tour lines millimeter by millimeter­whether manually or by automaticcorrelation-seems archaic. And despite theaccomplishments in orthophoto production,compilation and identification of planimetricdetail is still a very human-dependent opera­tion.

In 1961, another distinguished past Presi­dent and Honorary Member, Talbert Ab­rams, predicted in Photogrammetric En­gineering that aerial photographs are obso­lete and would shortly be replaced by all­weather radar. True enough, next year wewill witness the launch of Seasat-A, carryinga radar which can resolve 25 meters on theEarth's surface from orbital altitudes. Andwe have already seen enormous areas of theEarth covered by high-quality radar imagesfrom aircraft. But despite the obvious advan­tage of the all-weather capability of radar, solong as the human eye responds to the samewavelengths as optical systems, there is little

reason to fear for the future of conventionalphotography, either from aircraft or space­craft.

Neither am I confident that all of thephotogrammetrist's problems of geometryand interpretation will be solved by theubiquitous computer. There is a greattechnological appeal to solid-state imagesensors, data transmission systems, andcomputer processing of digital image data.But limitations on detector production andtransmission bandwidths, and the still con­siderable costs of useful computer process­ing, will restrict such systems to eitherlow-resolution or limited-area coverage forsome time to come. A 15 by 15 mm chip of anexisting panoramic camera photograph con­tains about the same amount of informationas a complete Landsat frame, and a singlepanoramic.exposure contains 650 such chips.The combination of photographic film, opti­cal processing, and eyeball interpretation isan astonishingly efficient filter system. Highresolution can be available where it is essen­tial and simply disregarded where it is not. I,for one, am not yet willing to trade humanintelligence for computational capability.

The fourth law of prophecy:

"It doth not profit a prophet to be too specific."

Still, what can one predict about the future?In a few years we will see operational

capability of the Space Shuttle, which willprovide us a new means of access to space.We can rather confidently expect that theeventual components of a Shuttle-basedEarth-imaging system will include:

• Continuously operating data-transmissionsatellites like Landsat with additionalspectral bands and improved resolution.

• Long-life unmanned recoverable satellitesproviding high-resolution film photographssui table for topographic mapping atreasonable scales.

• Geosynchronous systems providing trans­mitted data for real-time monitoring oftransient events.

We can expect continuing exploration ofthe solar system. We have already been tothe Moon with the first, and so far the only,-photogrammetrically satisfying systemwhich NASA has put together. We have beenpast Venus and have assembled astonishingphotocoverage of Mercury. Two spacecraftare right now operating on the surface ofMars. Pioneer II recorded the surface ofJupiter and is now on its way to Saturn. Andour photographs may yet discover the race ofsupermen to whom Erich Von Daniken as-

PHOTOGRAMMETRY: THE NEXT TWO-HUNDRED YEARS 577

cribes many of the unexplainable features onEarth.

I hope we can expect international coop­eration rather than competition in the furtherexploration of our planet and the universe.The Apollo-Soyuz mission last summer hasalready demonstrated that astronauts andspacecraft from the USA and the USSR canwork together productively. If photogram­metrists can head towards the number-oneposition in the area of cooperation and relin­quish our number-one position in competi­tion, it may well be the greatest break­through our country has yet had.

It may even be that Gomer McNeil and hisunderwater boys will bring back infi:tllibleevidence of the creatures in Loch Ness.

Further downstream we can expect thephotogrammetrist's job to be the mapping ofartificial worlds that man creates for himself.Extracting resources from space, locatingmanufacturing plants on other planets,generating solar power and transmitting it toEarth, and establishing space colonies mayappear visionary and outside our means andpriorities at this time. But they are no moreimprobable than it would have been to pre­dict crossing the Atlantic in three hours inthe days of clipper ship technology.

My final law of prophecy:

"When all else fails, be philosophic."

Many years ago I read a book on theologyby G. K. Chesterton. In examining the prob­lem of creation he raised the question, "Whyshould there be anything at all?" In away,that expresses my greatest concern for thefuture-will there be anything at all in 2176?A recent article in Science described a sur­vey at UCLA in which students and facultywere asked, "How long do you think ourcivilization will continue to exist"? Only 2percent said indefinitely, 50 percent saidless than 200 years, and more than 25 per­cent said society has a life expectancy lessthan their own.

We have all been subjected to any numberof scenarios for disaster. We are aware thathuman fertility is still an unsolved problemand that in 60 years there will be 11 billionpeople on Earth. We know that our expend­able resources are being depleted and ourrenewable resources being mismanaged, weknow we are running out of conventionalforms of fossil fuel, and we look for newways to use the Sun's energy. We know thatour water and our air are continuously beingfouled, and we know that our future may

well depend upon our ability to recycle ev­erything we use.

Meanwhile, every morning we read ofanother government or corporate executivewith his hand in the public till. All aroundthe globe people are killing each other forreasons too abstruse for most of us to com­prehend, and the hands on the doomsdayclock of the Bulletin of the Atomic Scientistsmove ever closer together as the major pow­ers sell sophisticated weapons to all sides.We continually ask ourselves whether weare too primitive for peace or too advancedfor war.

For sure we need not only new ideas, weneed particularly the wisdom to know whatto do with our new-found knowledge. Forsure we need to communicate with oneanother. But still something is missing!

A few years ago I stood in St. Peter'ssquare in Rome and watched Venus settingbehind the great cathedral. And I remem­bered the apostle's words, "Above all thingshave a constant mutual charity amongyourselves-for charity covers a multitude ofsins."

We know that photogrammetry can helpdiscover new resources, can monitor pollu­tion and inventory crops, can map the conti­nents and the oceans, can help predict andalleviate natural disasters, and can extendmankind's realm to the limits of the solar sys­tem. Our profession can contribute as muchas any other to the future well-being of man­kind. But we cannot wait for the propitioustime to begin the work of the future. Behold,now is the propitious time! The future willnot burst upon us like a new sunrise, but isright now being formed in the work of ourhands, our minds, and our spirit. That spiritneeds to be motivated by something morethan the simple instincts of self-preservationand self-aggrandizement. In order to guidethe forces of technology we need a clearerunderstanding not only of where we are go­ing, but why. We need to comprehend thatthe real objective of our work is the better­ment of the condition of our fellow man. Andthe reason for that service is not the intrinsicworth of Man-however high that maybe-but simply that it is commanded by theLord and Maker of us all.

As the French philosopher Teilhard deChardin wrote: "Some day after masteringthe winds, the waves, the tides, and gravity,we shall harness the energy of love-andthen for the second time in the history of theworld-mankind will have discovered fire."