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Popolni ortofoto je v urbanih okoljih boljši izdelek kot klasični ortofoto, ker so zgradbe na njem prikazane na pravilnem ravninskem položaju, vidna je tudi vsebina v njihovi okolici. Glavni cilj naše raziskave je bil preizkusiti dva postopka izdelave popolnega ortofota: a) postopek na podlagi digitalnega modela reliefa in digitalnega modela zgradb ter b) postopek samodejne izdelave popolnega ortofota. Raziskavo smo izvedli na dveh študijskih območjih v mestni občini Ljubljana. Oba postopka in izdelane popolne ortofote smo primerjali s klasično izdelanim ortofotom, ocenili smo tudi časovno komponento izdelave. Za popolni ortofoto potrebujemo aerofotografije z večjim prekrivanjem kot za izdelavo klasičnega ortofota, zato se čas aerofotografiranja poveča za približno 25 odstotkov. Čas obdelave, v primerjavi s postopkom izdelave klasičnega ortofota, se pri postopku samodejne izdelave popolnega ortofota zmanjša za faktor 0,75, oziroma se pri postopku izdelave popolnega ortofota na podlagi digitalnega modela reliefa in digitalnega modela zgradb poveča za faktor 2,3. Estetski videz samodejno izdelanega popolnega ortofota je nekoliko slabši le na robovih streh zgradb, ki so rahlo nazobčane. Če upoštevamo vse navedene vidike, je samodejno izdelan popolni ortofoto konkurenčen klasičnemu ortofotu. True orthophoto is a better product than a classical orthophoto in urban areas, because buildings are depicted in the correct plane position, and the content around the building is also visible. The main goal of our research was to verify two approaches of a true orthophoto production: a) true orthophoto production based on digital terrain model and digital building model, and b) automatic true orthophoto production. We performed the research in two test areas within the Municipality of Ljubljana. We compared the both procedures and the produced true orthophotos with the classical orthophoto, and assessed the production time component as well. To produce true orthophoto, larger overlapping of aerial images is required, thus the time for aerial surveying is increased by approximately 25 percentage. The time of work, compared to classical orthophoto production, is lower by the factor 0.75 for automatically produced true orthophoto, and is greater by the factor 2.3 for the true orthophoto based on digital terrain model and digital building model. Aesthetic appearance of automatically produced orthophoto has only minor shortcomings on the buildings% roof edges which are slightly serrated. Considering all the mentioned aspects, the automatically produced true orthophoto is competitive with the classical orthophoto. |
