Hawaii Coastal Imagery 2015

Orthoimagery of the coastlines of the Main Hawaiian Islands, 2015; Resource Mapping Hawaii conducted aerial surveys between August - November 2015 to collect imagery at a spatial resolution of 2cm. Due to flight restrictions around airports and military bases, some areas of the coastline were omitted. The dataset covers an approximate 200m swath, with a variable amount of shoreline and nearshore water, and was processed into tiles of orthoimagery for GIS analysis of marine debris. Brian Neilson (Hawaii Department of Land and Natural Resources; [e-mail]) was the Principal Investigator on the “Hawaiian islands marine debris aerial imagery surveys” component of the PICES Project “Effects of marine debris caused by the Great Tsunami of 2011” funded by the Ministry of the Environment of Japan. The project coordinator was Dr. Alexander Bychkov ([e-mail]). In 2020, Ross Winans ([e-mail]) enhanced the imagery by: removing excessive no-data (including cropping out areas of no-data in some images); creating alpha masks with GINA's gdal_trace_outline for transparency since the data uses "0" and "255" for valid data; for areas in the data where places were "patched" with a second, overlapping image swath at a later date, the image that best aligned with the GIS labeled marine debris objects described in Moy et al. (2018) were chosen and the unused overlap was cropped out, resulting in a data set that is now tiled edge-to-edge with no overlap. For further information, please contact the Hawaii Statewide GIS Program at [e-mail]. Credits: Resource Mapping Hawaii; Ross Winans2015年夏威夷主岛海岸线正射影像（orthoimagery）数据集：由夏威夷资源测绘（Resource Mapping Hawaii）团队于2015年8月至11月开展航空测绘，采集空间分辨率（spatial resolution）为2厘米的影像。受机场及军事基地周边飞行管制限制，部分海岸线区域未被纳入测绘范围。该数据集覆盖约200米宽的航带（swath）范围，包含长度可变的海岸线及近岸水域，经处理为正射影像瓦片（tiles）以支持海洋垃圾的地理信息系统（GIS）分析。布莱恩·尼尔森（Brian Neilson，夏威夷土地与自然资源部；[e-mail]）为“夏威夷群岛海洋垃圾航空影像测绘”子项目的首席研究员（Principal Investigator），该子项目隶属于日本环境省资助的北太平洋海洋科学组织（PICES）项目“2011年大海啸引发的海洋垃圾影响”。本项目协调员为亚历山大·比奇科夫博士（Dr. Alexander Bychkov；[e-mail]）。2020年，罗斯·怀南斯（Ross Winans；[e-mail]）对影像进行了优化处理：移除冗余无数据（no-data）区域（包括裁剪部分影像中的无数据区块）；由于原数据以"0"和"255"标识有效数据，因此使用GINA的gdal_trace_outline工具生成alpha遮罩（alpha masks）以实现透明化；针对后期通过二次重叠航带补测的区域，选取与Moy等人（2018）中标记的GIS海洋垃圾对象匹配度最高的影像，并裁剪掉未使用的重叠区域，最终得到无重叠、边缘无缝拼接的瓦片数据集。如需获取更多信息，请联系夏威夷全州地理信息系统项目组，邮箱：[e-mail]。鸣谢：夏威夷资源测绘团队；罗斯·怀南斯。