2017 Unmanned aerial system (UAS)-derived orthoimage mosaics and digital terrain models of NE distal lava flow margin, Holuhraun lava flow-field, Vatnajökull National Park, Iceland

Using Phantom 4 Pro imaging systems, aerial images were acquired over short section of the NE Holuhraun lava flow margin, adjacent interior and adjacent river systems. Images were initially geocoded using the device's onboard GPS. Final products were coregistered to more precise geocoded image data collected later in 2016. Images were processed into geodetically-controlled digital terrain models (DTMs) and orthomosaics using the commercial software package Pix4Dmapper Pro version 2.0.81. In Pix4Dmapper Pro, data products were geocoded by attributing the 3D coordinates of geocoded image coregistration targets to corresponding pixels in a subset of 2D images. The 2016 image data used for coregistration utilized DGPS measurements. To estimate the localization accuracy, we used a network of N = 16 coregistration points; the resulting mean of the root mean square error (RMSE) of x, y, and z directions (i.e., latitude, longitude, and elevation) is 3.5 cm. Both the DTM and orthomosaic products have a spatial resolution of 2.3 cm/pixel, but the DTM has an effective resolution of ~5 cm/pixel. <br><b>Topic Categories (ISO 19115)</b>elevation, geoscientificinformation, imageryBaseMapsEarthCover<br><b>Feature and Attribute Definitions</b>A georeferenced raster displaying elevation data generated from digital camera image data using multi-view stereophotogrammetry methods.<br><b>Date of Content</b>2017-07-25 to 2017-07-28<br><br><br><i>For inquiries regarding the contents of this dataset, please contact the Corresponding Author listed in the README.txt file. Administrative inquiries (e.g., removal requests, trouble downloading, etc.) can be directed to [e-mail]</i><br><i>This item is part of Unmanned aerial system (UAS)-derived orthoimage mosaics and digital terrain models of the northeastern portion of the Holuhraun lava flow-field, Iceland</i>

使用Phantom 4 Pro影像系统，针对冰岛东北部霍鲁赫拉恩（Holuhraun）熔岩流边缘的短区段、毗邻的熔岩流内部区域及相邻河流水系采集了航空影像。影像最初通过设备内置的GPS进行地理编码。最终成果与2016年后期采集的更精确的地理编码影像数据进行了配准。本数据集使用商业软件Pix4Dmapper Pro 2.0.81版，将影像处理为受大地测量控制的数字地形模型（Digital Terrain Model, DTM）与正射影像镶嵌图。在Pix4Dmapper Pro中，通过将地理编码影像配准靶点的三维坐标赋予部分二维影像中的对应像素，完成数据产品的地理编码。本次配准所使用的2016年影像数据采用了差分GPS（Differential GPS, DGPS）测量数据。为评估定位精度，本研究使用了包含16个配准靶点的网络；最终得到x、y、z方向（即纬度、经度与高程）的均方根误差（Root Mean Square Error, RMSE）均值为3.5厘米。数字地形模型与正射影像镶嵌图的空间分辨率均为2.3厘米/像素，但数字地形模型的有效分辨率约为5厘米/像素。<br><b>主题分类（ISO 19115）</b>高程、地球科学信息、地表覆盖影像底图<br><b>要素与属性定义</b>本数据集为经过地理配准的栅格数据，通过多视图立体摄影测量方法由数码相机影像数据生成，用于展示高程信息。<br><b>内容日期</b>2017年7月25日至2017年7月28日<br><br><br><i>若需咨询本数据集的具体内容，请联系README.txt文件中列出的通讯作者。行政类咨询（如数据移除申请、下载故障等）可发送至邮箱[e-mail]</i><br><i>本数据集隶属于冰岛霍鲁赫拉恩熔岩流场东北部区域的无人机系统（Unmanned Aerial System, UAS）衍生正射影像镶嵌图与数字地形模型数据集组</i>