Absolutely. Photogrammetry is more important today than it has been at any other time. Many of the current images people see in 3D city models, land use planning, environmental and applications involving the determination of landscape change are directly dependent upon photogrammetric products and services. Photogrammety sits at the forefront of many 3D applications because it can provide digital data immediately, and processing tools for that information are also innovative. Lastly, photogrammetry provides one of the few qualitative approaches for geospatial information available through standardisation of testing procedures and specifications.
PhoÂtogramÂmeÂtry has come a long way since itâs earÂliÂest beginÂnings. That growth has been expoÂnenÂtial and the develÂopÂments have often revÂoÂluÂtionÂaryââânew optics, innoÂvÂaÂtive algoÂrithms, higher speed, higher qualÂity images, for examÂple. Many peoÂple outÂside of the geospaÂtial may not be aware of the size of the phoÂtogramÂmeÂtry secÂtor and the numÂber of peoÂple employed in it. The InterÂnaÂtional SociÂety of PhoÂtogramÂmeÂtry and Remote SensÂing (ISPRS) is the largest organÂiÂsaÂtion that repÂreÂsents these indiÂvidÂuÂals and organÂiÂsaÂtions. It supÂports this work around the world in a variÂety of ways includÂing, eduÂcaÂtion, research, conÂferÂences and publications.
My first involveÂment with phoÂtogramÂmeÂtry began when I studÂied forestry in northÂern Canada. It was there that I learned about stereÂoscopy, calÂcuÂlatÂing basic stereo photo geomÂeÂtry and became iniÂtiÂated into the process of air photo interÂpreÂtaÂtion. That was not an easy task for a new forester because one had to know how speÂcific tree species grew (which made for interÂestÂing learnÂing at the same time).Â But it drove home the point that phoÂtogramÂmeÂtry was not solely about the images, but also about the interÂpreÂtaÂtion of those images. And that has not changed over time, although todayâs digÂiÂtal proÂcessÂing of images is more auÂtoÂmated. Yet, when one talks to well expeÂriÂenced phoÂtogramÂmetriÂcistsÂ today, they conÂtinue to menÂtion the interÂpreÂtive eleÂments of the process.
We see phoÂtogramÂmeÂtry used in feaÂture extracÂtion appliÂcaÂtions today. BoundÂaries can be idenÂtiÂfied and vecÂtorised, thereby makÂing them availÂable for use in geoÂgraphic inforÂmaÂtion sysÂtems (GIS). While GIS can import airÂborne images as rasters, these images reach their greatÂest âvalueâ through digiÂtiÂsaÂtion. Why? Because lines, points and arcs are spaÂtially sigÂnifÂiÂcant for spaÂtial analyÂsis within a GIS and can be used with spaÂtial operÂaÂtors to deterÂmine relaÂtionÂships to other data. That is not to say that rasters canÂnot be analysed spaÂtially, since, they too , are geo-referenced pixel-by-pixel.Â This is exhibÂited through GIS softÂware such as IDRISI.
Upon first arrivÂing in GerÂmany I wrote an artiÂcle about the develÂopÂment of triÂanÂguÂlated irregÂuÂlar netÂworks (TIN). The idea behind the artiÂcle was to conÂstruct a hisÂtory of the develÂopÂment of digÂiÂtal terÂrain model (DTM). Not long afterÂward, I received a pleasÂant note informÂing me about the powÂers of phoÂtogramÂmetÂric derived terÂrain modÂels. The note was signed by Dr. Fritz AckÂerÂmann of the InstiÂtute of PhoÂtogramÂmeÂtry at Stuttgart UniÂverÂsity. He kindly pointed out how the process worked and why it was imporÂtant to underÂstand. Later we ended up pubÂlishÂing an artiÂcle he preÂsented. AckÂerÂmann became the Founder of INPHO ââwhich was recently merged into Trimble.
The inteÂgraÂtion of phoÂtogramÂmetÂric derived images with laser based meaÂsureÂments is a growÂing field today. In prinÂciÂple, the idea is to develop high resÂoÂluÂtion digÂiÂtal eleÂvaÂtion modÂels (DEM) that show 3D buildÂing modÂels together with the detailed textures.
AddiÂtionÂally, the derivaÂtion of buildÂing and other heights from phoÂtogrameÂtry is related to the flight geomÂeÂtry of the airÂcraft. GeospaÂtially this has imporÂtant impliÂcaÂtions where inerÂtial guidÂance sysÂtems, often based on GPS, are used to ensure that airÂcraft fly level and straight. Thus we see a comÂbiÂnaÂtion of geospaÂtial techÂnoloÂgies that must work together to enable the process of aerÂial phoÂtogÂraÂphy to take place. The camÂeras used in these processes must also then be stanÂdardÂised and specÂiÂfiÂcaÂtions made available.
The entire field of phoÂtogramÂmeÂtry conÂsists of sevÂeral camÂera manÂuÂfacÂturÂers. They come together using simÂiÂlar test locaÂtions and proÂceÂdures that enable the global comÂmuÂnity to underÂstand, gauge and interÂpret varÂiÂous aerÂial prodÂucts in a stanÂdardÂised way. EuroSDR is one organÂiÂsaÂtion involved in develÂopÂing these proÂceÂdures and processes. This year, one of the winÂners of the Carl PulÂfrich Award, Michael Cramer of UniÂverÂsity Stuttgart is highly noted for his work in thisÂ area.
The qualÂity aspect of phoÂtogramÂmeÂtry work is imporÂtant. AttendÂing most events that include disÂcusÂsion around phoÂtogramÂmeÂtry will invariÂably lead to a disÂcusÂsion about data qualÂity issues and hardÂware specÂiÂfiÂcaÂtions. At all times phoÂtogramÂmetrists are interÂested in the perÂforÂmance of equipÂment and ensurÂing that the data proÂduced from it are quanÂtifiÂable and repeatÂable. This has imporÂtance to the interÂnaÂtional geospaÂtial comÂmuÂnity. In on sense it not only builds trust between manÂuÂfacÂturÂers and users based on underÂstandÂing, but it also sets in motion the proÂceÂdures for reachÂing interÂnaÂtional stanÂdards and proÂcessÂing approaches from disÂparate locaÂtions, resources and difÂferÂent appliÂcaÂtions. This helps to build capacÂity and smooth the growth toward greater use of these techÂnoloÂgies and applications.
PhoÂtogramÂmeÂtry appliÂcaÂtions excel at proÂvidÂing accuÂracy down to the range of cenÂtimeÂters. This places these devices in close agreeÂment with GPS refÂerÂence netÂworks, meanÂing that the appliÂcaÂtions can be couÂpled together over wider regions.
But it would be incorÂrect to assume that phoÂtogramÂmeÂtry only perÂtains to the camÂeras themÂselves. It includes all of the equipÂment and processes conÂnected to the proÂducÂtion of airÂborne data and derived data prodÂucts. This includes stereÂoÂplotÂters, image servÂing and image proÂcessÂing etc.
PhoÂtogramÂmeÂtry is growÂing in imporÂtance and use. New develÂopÂments across the work flows incorÂpoÂratÂing phoÂtogramÂmeÂtry are conÂtinÂuÂally expandÂing opporÂtuÂniÂties for buildÂing appliÂcaÂtions using this inforÂmaÂtion. There are speÂcific disÂtincÂtions between between satelÂlite based imagery and phoÂtogramÂmeÂtry derived imagery from airÂcraft and UAV. Higher adaÂpÂataÂbilÂity, increased resÂoÂluÂtion, abilÂity to inteÂgrate with addiÂtional senÂsors and timeÂliÂness are just a few of the advanÂtages worth considering.
The role of phoÂtogramÂmeÂtry in the geospaÂtial indusÂtry is at the foreÂfront shapÂing change, innoÂvaÂtion and supÂportÂing higher demands for underÂstandÂing planÂeÂtary change.
Jeff Thurston is ediÂtor, Europe, MidÂdle East and Africa for V1 MagÂaÂzine and V1 Energy MagÂaÂzine. He is Co-founder of Vector1 Media.