Fotoplanų, sudarytų ultralengvu orlaiviu atliktos aeronuotraukos pagrindu, geometrinis tikslumas

Abstract

Šiame straipsnyje yra pristatomi fotoplanai, sudaryti ultralengvu orlaiviu atliktos aerofotonuotraukos pagrindu. Aptariami du aerofotografavimo (i) esant 1600 m altitudei, vaizdu gardel s dydis 50 cm ir (ii) esant 900 m altitudei, vaizdu gardel s dydis 30 cm bei keturi fotoplanu gamybos technologijos variantai – (i) naudojama tik aerofotografavimo metu užfiksuota informacija, (ii) papildomai naudojami vietov je prieš aerofotografavima paženklinti ir išmatuoti atramos taškai, (iii) pagal topografinius žem lapius M1:10000 sukuriamas skaitmeninis vietov s reljefo modelis, kuris papildomai naudojamas aerotrianguliacijos bei ortotransformavimo procese, ir (iv) atramos taškai bei atskirai sukurtas reljefo modelis, papildomai naudojami kartu. Ivertintas gaunamu fotoplanu geometrinis tikslumas. Ryškiu vietov s objektu pad ties vidutin kvadratin paklaida ORT10LT atžvilgiu maž ja pasitelkiant papildoma informacija nuo 5,53 m iki 2,82 m, taciau šis sumaž jimas nustatytas tik atvirose vietov se. Fotoplanu geometrinis tikslumas atvirose vietov se esmingai pager ja, jei aerofotografavimo altitud sumažinama nuo 1600 m iki 900 m bei fotoplanu gamyboje panaudojami atramos taškai – vidutin kvadratin paklaida mažta iki 1,39 m. Sudarant fotoplanus panaudojant atramos tašku informacija, praktiškai pašalinama sistemin paklaida. Daroma apibendrinanti išvada, kad fotoplanai, pagaminti ultralengvo orlaivio atliktu aerofotonuotraukos pagrindu esant 1600 m altitudei, gali buti naudojami sprendžiant šiuolaikin s sklypin s mišku inventorizacijos ar panašius uždavinius

This paper introduces orthophoto maps that have been developed using aerial images grabbed from ultra-light aircraft. Two variants of flying altitude: (i) 1600 m, corresponding to 50 cm pixel size of digital aerial images and (ii) 900 m, or 30 cm pixel size and four technological solutions to develop the orthophoto maps are discussed: (i) information collected during the aerial photography only is used, (ii) field-premarked and surveyed ground control points are used additionally, (iii) digital elevation model developed using information available from topographic maps M1:10000 is used in aerial triangulation and orthorectification and (iv) ground control points and external digital elevation model are additionally used together. Geometrical accuracy of the orthophoto maps created has been evaluated. The root mean square error in positioning of clearly identifiable objects on the image as compared with the same objects on orthophotographic map ORT10LT tends to decrease if auxiliary information is used from 5.53 m down to 2.82 m, however just on open areas. Lowering the flying altitude from 1600 down to 900 m and using minimal amount of ground control points result in significant decreasing of root mean square error down to 1.39 m. Using of ground control points has been found to remove the bias. The general conclusion has been made that the photomaps developed using materials of ultra-light aircraft based on 1600 m flying altitude aerial photography suit for solving tasks of conventional stand-wise forest inventory. Forest inventory, aerial photography, ultra-light aircraft, photomap, geometrical accuracy