Photogrammetric scans of North American Glacier Aerial Photographs, 1991. Roll 1 tiffs - Fiducials

Introduction: Between 1958 and 1999, Austin Post led the USGS collection of aerial imagery of North American glaciers. These images are primarily vertical stereo black and white images, although single oblique images, as well as color images have been collected. The glaciers of North America were the subjects, and the digital products made available here serve to document the changes that have occurred to the glaciers over the past 5 decades. The purpose of this project is to preserve the data contained within these film images in a digital format for future analysis of North American glacier change. Package Layout: 1. The first level contains an overall data set of image metadata from 1964 - 1997 (nagapData.csv) and an R script (searchData.R) with instructions on how to search and subset the data. fileLayout.pdf shows the file structure and folder contents visually. There are also three kml files with flight path information by decade. 2. The second level is the year in which the pictures were taken. There are 32 years with images from 1964 – 1997. The majority of these folders are jpegs with notes provided by Austin Post. They also contain a year-specific csv (YYYY.csv) that contains image metadata for the entire year (date, roll numbers, location name, longitude, latitude, altitude, media, and comments). The overall data set (nagapData.csv) is the aggregate of each individual “YYYY.csv” file. 3. The glacier photos are located at the third level (this level). The folders at this level are distinguished by camera roll number (1, 2, etc.), and image type (thumbnail, jpeg, or tif); some also contain fiducial and oblique image folders. This level primarily contains image files of aerial photos as either thumbnails, jpegs, or tifs. It also includes a csv with image metadata specific to each roll (date, roll numbers, location name, longitude, latitude, altitude, media, and comments), a text file (info.txt) with camera specifications unique to each image, and a text file (histo.txt or matchReport.txt) with color information and scanner specifications unique to each image.

数据集介绍：
1958年至1999年间，奥斯汀·波斯特（Austin Post）主持了美国地质调查局（United States Geological Survey, USGS）的北美冰川航空影像采集工作。该系列影像以垂直立体黑白航空影像为主，同时也收录了单张倾斜影像与彩色影像。本次数据集以北美洲冰川为研究对象，本次公开的数字化产品旨在记录近50年来这些冰川发生的变化。本项目的核心目标是将这些胶片影像中的数据以数字化形式永久留存，以供未来开展北美冰川变化相关研究分析使用。

数据包布局：
1. 第一层级包含1964年至1997年的全量影像元数据集（nagapData.csv），以及一份用于指导数据检索与子集提取的R脚本（searchData.R）。fileLayout.pdf以可视化形式展示了文件结构与文件夹内容。此外还包含三份按十年划分的飞行路径信息KML（Keyhole Markup Language）文件。
2. 第二层级以影像拍摄年份作为目录划分依据。本次数据集涵盖1964年至1997年共计32个年份的影像数据。大部分文件夹内存储了奥斯汀·波斯特（Austin Post）标注说明的JPEG格式影像，同时还包含一份对应年份的专属元数据CSV文件（"YYYY.csv"，其中YYYY为具体拍摄年份），该文件记录了全年影像的完整元数据，包括拍摄日期、胶卷编号、地点名称、经度、纬度、拍摄高度、介质类型与备注信息。全量元数据集nagapData.csv为各年份"YYYY.csv"文件的聚合汇总。
3. 第三层级即为冰川影像的具体存储目录。该层级的文件夹以相机胶卷编号（1、2等）与影像类型（缩略图、JPEG或TIFF）进行区分，部分文件夹还包含框标影像与倾斜影像子文件夹。本层级主要存储各类格式的航空影像文件，包括缩略图、JPEG与TIFF格式。此外还包含一份针对单卷胶卷的专属元数据CSV文件，内容涵盖拍摄日期、胶卷编号、地点名称、经度、纬度、拍摄高度、介质类型与备注信息；一份记录每幅影像专属相机参数的文本文件（info.txt）；以及一份包含色彩信息与扫描仪专属参数的文本文件（histo.txt或matchReport.txt）。