Land cover classification of polygonal tundra from small-format aerial photography, Samoylov Island (Lena Delta, Siberia), summer 2008, with link to ESRI grid files@en

Polygonal tundra on Samoylov Island (Lena Delta, Siberia) was mapped from small-format aerial photography. Sub-metre resolution aerial images were obtained by mounting two Nikon D200 cameras on a helium-filled dirigible. Images were acquired in the visible (VIS) and near-infrared (NIR) ranges (together referred to as the VNIR range). The internal IR-filters were removed from the cameras in a laboratory (LPD LLC, USA), allowing them to capture a maximum range from about 330 to 1200 nm. A Schneider Kreuznach B+W 486 UV-IR cut filter was used for one of the cameras to obtain images in the VIS range, from about 400 to 690 nm, while the second camera was fitted with a Schneider Kreuznach B+W IR-filter 093 to acquire images in the NIR range, above about 830 nm. Flights took place at noon on sunny, cloudless days (August 1, August 9 and August 15, 2008). An average flying altitude of 750 m resulted in a pixel size of about 0.18 m. The aerial image data were processed using ENVI 4.7 image processing software. NIR images were registered onto VIS images using the automatic image-to-image registration with an average root mean square error (RMSE) of 0.53 pixels. The resulting VNIR images were then georeferenced to UTM (WGS84, 52N) based on an orthomosaic of the island from 2007 with a resolution of 0.3 m. The nearest neighbour algorithm was chosen for all resampling operations. […]西伯利亚勒拿河三角洲萨莫伊洛夫岛的多边形苔原通过小画幅航空摄影完成了制图。研究通过在氦气飞艇上搭载两台尼康D200相机，获取了亚米级分辨率航空影像。影像采集波段涵盖可见光（VIS）与近红外（NIR），二者合称为VNIR波段。美国LPD有限责任公司的实验室移除了两台相机的内置红外滤镜，使其可捕捉约330 nm至1200 nm的光谱范围。其中一台相机加装了施耐德克鲁茨纳奇B+W 486型UV-IR截止滤镜，以获取约400 nm至690 nm的可见光波段影像；另一台相机则搭载施耐德克鲁茨纳奇B+W IR滤镜093，用于采集约830 nm以上的近红外波段影像。航空飞行于2008年8月1日、8月9日及8月15日的晴朗无云正午时段开展。平均飞行高度为750 m，由此得到的影像像素尺寸约为0.18 m。航空影像数据采用ENVI 4.7图像处理软件进行后期处理。通过自动图像配准算法将近红外影像匹配至可见光影像，平均配准均方根误差（RMSE）为0.53像素。随后，基于该岛2007年分辨率为0.3 m的正射镶嵌图，将生成的VNIR影像进行地理配准至UTM（WGS84，52N）坐标系。所有重采样操作均采用最邻近算法。[……]