Photogrammetric scans of aerial photographs of North American glaciers, 1992. Roll 5 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.

引言：
1958年至1999年间，奥斯汀·波斯特（Austin Post）牵头开展了美国地质调查局(USGS)的北美冰川航空影像采集项目。本次采集的影像以垂直立体黑白航空影像为主，同时涵盖单张倾斜影像与彩色影像。数据集以北美冰川为拍摄主体，此处公开的数字化成果旨在完整记录近50年来北美冰川的变化情况。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留存，以供未来开展北美冰川变化相关的系统性研究分析。

文件结构说明：
1. 一级目录：包含1964年至1997年的全量影像元数据集（nagapData.csv），以及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整体文件结构与各文件夹的具体内容。此外还包含3个按年代划分的飞行路径信息KML文件。
2. 二级目录：以影像拍摄年份命名，涵盖1964年至1997年间的32个有影像记录的拍摄年份。多数年份文件夹内包含奥斯汀·波斯特标注的JPEG图片，同时还包含对应年份的专属元数据CSV文件（YYYY.csv，其中YYYY为对应拍摄年份），该文件记录了全年影像的完整元数据信息，包括拍摄日期、胶卷编号、拍摄地点名称、经度、纬度、拍摄高度、介质类型与备注说明。全量元数据集nagapData.csv即为各单个YYYY.csv文件的汇总整合版本。
3. 三级目录：即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TIF）进行区分命名，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航空影像文件，格式涵盖缩略图、JPEG与TIF。此外还包含针对每个胶卷的专属影像元数据CSV文件（记录内容与前述YYYY.csv一致）、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）。