Photogrammetric scans of aerial photographs of North American glaciers, 1997. Roll 2 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. File 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）北美冰川航空影像的采集项目。该数据集以垂直立体黑白航空影像为主，同时也收录了单幅倾斜航空影像与彩色航空影像。本次采集以北美冰川为研究对象，本平台提供的数字化成果旨在记录近50年来北美冰川的动态变化。本项目的核心目标是将这些胶片影像中的原始数据以数字化格式永久保存，以供未来开展北美冰川变化相关的研究分析。

文件结构说明：
1. 第一层级包含1964-1997年全数据集的影像元数据文件（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完整的文件结构与文件夹内容。此外还包含三份按年代划分的飞行路径KML（Keyhole标记语言, KML）文件。
2. 第二层级为影像拍摄年份。本次数据集涵盖1964年至1997年共32个年份的影像。大部分文件夹内存储了附带奥斯汀·波斯特注释的JPEG（联合图像专家小组格式, JPEG）影像，同时还包含对应年份的专属元数据CSV文件（YYYY.csv），该文件记录了全年所有影像的元数据信息，包括拍摄日期、胶卷编号、地点名称、经度、纬度、海拔、介质类型与备注。全数据集元数据文件nagapData.csv即为各年度YYYY.csv文件的汇总版本。
3. 第三层级为冰川影像的具体存储位置。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（标记图像文件格式, TIFF））进行分类，部分文件夹还包含基准点影像与倾斜影像的子文件夹。本层级主要存储航空照片的影像文件，格式涵盖缩略图、JPEG或TIFF。此外还包含针对每个胶卷的专属元数据CSV文件（涵盖拍摄日期、胶卷编号、地点名称、经度、纬度、海拔、介质类型与备注）、记录单张影像专属相机参数的文本文件（info.txt），以及包含单张影像色彩信息与扫描仪参数的文本文件（histo.txt或matchReport.txt）。