Daniel B Fagre Lisa A McKeon Michelle M Manly 2017 Vector Digital Data Set (Polygon) Reston, VA U.S. Geological Survey https://dx.doi.org/10.5066/F7P26WB1 These polygon features represent digitization of the glacier margins for the 37 named glaciers of Glacier National Park (GNP) and the 2 glaciers along the border of GNP derived from aerial images acquired on September 11, 12, 14, 15, 1998. The polygons represent only the main body portion of the glacier as they appeared in the 1998 imagery. Disconnected patches are not included as this dataset represents only the main body features. Polygons were digitized from orthorectified aerial images with initial digitization completed in 2001 by Michelle Manly, University of North Dakota graduate student. This set of polygons represents a thorough review with revisions to the initial dataset based on local knowledge and improved satellite imagery acquired in 2015. In several cases, the much higher resolution 2015 imagery revealed features, such as debris covered ice, where 1998 image analysis had deemed bedrock and actual margins had to be re-evaluated. A Wacom Pro digital tablet was used by USGS staff to trace outlines and make revisions to the original margins. Glaciers were digitized at 1:2000 scale. Since multiple images in time series contribute to this analysis, if previous image showed perennial snow that was absent from the glacier (bedrock visible), then that portion was deemed "seasonal/perennial snow" in subsequent photos and not included in the digitization of 1998 glacier margins. To develop a time series and history of glacier recession in Glacier National Park. This dataset delineates the 1998 perimeters of the named glaciers of Glacier National Park. Establishing the rates of glacier retreat are key to understanding the Glacier National Park ecosystem and future state of resources. For instance, glacial meltwater provides critical habitat for endangered stream insects. More broadly, retreating glaciers are indicative of long term climate change and have hydrologic and ecologic importance to many park resources. Glaciers and their retreat are of great interest to park visitors and the American public and are part of Glacier National Park's appeal. This is important because Glacier National Park is a major driver of the regional economy. Appropriate use of these data include comparing Glacier National Park's glacier area from different periods such as previous/subsequent years included in the data release, and from different parts of the world. The change in glacier area can be used to test models of glacier-climate interactions, and to estimate glacier contributions to streamflow. This dataset represents the named glaciers of Glacier National Park (including 2 nearby glaciers on U.S. Forest Service’s Flathead National Forest land). The "named glaciers" constitute a subset of the total snow and ice inventory of the park and do not represent a comprehensive accounting of all glaciers or permanent ice features in the park. A subsequent dataset will be published that will include all cryospheric features and better represent the hydrologic contribution of ice and snow features of the park. As glaciers shrink in size they leave behind remnants of ice and often break up into pieces of ice. The criteria used for determining which bodies of ice constituted a glacier were a) using the largest ice body remaining that was obviously separated by exposed rock from other ice bodies, and b) if the largest ice body was connected to other ice bodies by narrow strips of snow or ice, those other ice bodies were excluded if the strips was thought to be snow or if the (barely) attached ice body was very small relative to the main ice body and was not functioning as part of the glacier, e.g. showing any evidence of movement or contributing ice to the main body. An exception was made if the glacier had separated into two ice bodies of approximately the same size which were each large enough to be glaciers (0.1 km2) and/or were narrowly separated by a ledge where the upper ice body was still delivering ice to the lower body. 19980911 19980912 19980914 19980915 Observed Complete None planned -114.235885559 -113.503240961 49.00028351 48.308979051 None glacier glacier area margin cryosphere 1998 aerial imagery alpine glacier glacier retreat USGS Thesaurus snow and ice cover ISO 19115 Topic Category environment geoscientificInformation USGS Metadata Identifier USGS:58af765ce4b01ccd54f9f5e7 None Glacier National Park GLAC Flathead County Glacier County United States North America National Park Service NPS Common geographic areas Montana None None U.S. Geological Survey Daniel B Fagre Research Ecologist mailing address

PO Box 169

West Glacier MT 59936 USA 406-888-7922 406-888-7923 dan_fagre@usgs.gov Michelle M Manly (University of North Dakota) Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.4.1 (Build 5686) Service Pack N/A (Build N/A) All orthorectified imagery was visually checked for accuracy against the DOQs used for ground control coordinate information. All final orthorectified images were determined to be of appropriate quality for this study, including the images with an RMSE greater than 1.0. Between three and five scientists digitized and reviewed the mapped perimeters of all named glaciers using the best images available and industry-standard mapping software. The location of mapped ice was finalized by consensus. Potential inaccuracies inherent to the imagery were not addressed except by excluding images that were visually distorted. Mapped perimeters were compared to a limited number of ground surveys using Global Positioning Systems (GPS). For each glacier, supplemental imagery was used to aid in interpreting the exact glacier perimeter. Parts of some perimeters were covered by rock debris or seasonal snow. Some glaciers, particularly those facing north or northeast, were deep in shadows and details in the shadowed areas were difficult to discern. Oblique terrestrial and aerial photography were compared to help delineate the perimeter in those cases. Photographs of all glaciers shot by John Scurlock in 2009 were the most useful. These are available at http://glaciers.research.pdx.edu/image-galleries/Lewis-Range-MT No formal logical accuracy tests were conducted. Margins were delineated based on visual interpretation of glacial features, supplemented by cross-checking with multiple other images, both terrestrial oblique photography and other sources of aerial photography. GoogleEarth was used for interpreting 3-dimensional aspects of images from aerial and satellite photography. There were no expected ranges per se. The expectation was that glaciers would shrink or possibly be static in size but would not grow. This occurred. Where glacier perimeters seemed as if they didn’t reflect likely location in the basin topography, extra efforts were made to assess whether rock debris was covering ice. Data set is considered complete for the information presented, as described in the abstract. The focus of this dataset was on the named glaciers of GNP, which represent the majority of the glaciers in the park, however, small ice patches and remnant glacial ice were not included in this survey. In areas of heavy shading, image distortion, or where image quality was compromised in some way which made margin delineation uncertain, supplementary oblique images were used to aid in margin delineation. Users are advised to read the rest of the metadata record and record attributes for additional details. A formal accuracy assessment of the horizontal positional information in the data set has not been conducted. A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable. Michelle M Manly (University of North Dakota student) 19980912 Raster Digital Data (Aerial Imagery) West Glacier, MT USGS Glacier Field Station 15840 Digital and/or Hardcopy Resources 19980911 19980915 Observed Source Source information used in the development of the orthorectified imagery of which the 1998 glacier margins were digitized from. In 1998 the US Geological Survey contracted Map Inc., of Missoula, MT, to take aerial photographs of the mountainous regions of Glacier National Park, MT. Imagery was acquired on September 11, 12, 14, 15, 1998. The black and white photographs were taken at a 1:15840-scale, with an image resolution of 20 centimeters, film type 2405 B and W, Cal focal length = 152.258mm. The resulting images contained all glacier basins within GNP and were delivered as black and white prints (images reside with USGS office in West Glacier, MT). 19980911 To prepare the aerial imagery for analysis, photographs of the named glaciers were digitized and orthorectified by Michelle Manly, University of North Dakota graduate student. The first step in this process was converting the selected aerial negatives to diapositive format. The diapositives were scanned at 1500dpi, and burned to a compact disc. This process resulted in imagery with 27 cm ground resolution. 20010901 Orthorectification was done using Erdas Imagine (version 8.5). Photographs were entered into Orthobase in digital format along with a digital orthophoto quadrangle (DOQ) and a digital elevation model (DEM). Four basic steps are involved with the orthorectification process 1) defining the camera model, 2) point measurement, 3) triangulation, and 4) orthorectification. All orthorectified imagery was visually checked for accuracy against the DOQs used for ground control coordinate information. All final orthorectified images were determined to be of appropriate quality for this study, including the images with an RMSE greater than 1.0. 20011101 Import orthorectified image in to ArcGIS. Visually determine main body portion and digitize margin at 1:2000 scale with Wacom Pro digital tablet. In areas of heavy shading, image distortion, or where image quality was compromised in some way which made margin delineation uncertain, supplemental imagery from another date in 1998 (when possible) or other recent year was used to best determine margin. Users are advised to read the rest of the metadata record and record attributes for additional details. Oblique aerial photos from the USGS collection were also used to determine margin perimeter when source imagery was not adequate. 20160901 Vector G-polygon 39 Universal Transverse Mercator 12 0.9996 -111.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 Meter D_North_American_1983 GRS_1980 6378137.0 298.257222101 Attribute Table Table containing attribute information associated with the data set. Producer defined RECNO Record number: Unique numerical identifier Producer defined 1013 1601 X_COORD UTM X-coordinate, NAD 1983 UTM Zone 12N Producer defined 263431.844913511 314286.15231539 meters Y_COORD UTM Y-Coordinate, NAD 1983 UTM Zone 12N Producer defined 5355989.29268459 5430413.14778425 meters GLACNAME Glacier name Producer defined Name of glacier CLASSIFICA The portion of the glacier defined by the polygon Producer defined main body of glacier indicates the portion defined by the polygon to be the primary component of the glacier Producer defined YEAR Year of source data used to delineate glacier margins Producer defined 1998 year 1998 of Gregorian Calendar Producer defined SOURCE_SCA Scale of source data Producer defined 1:15840 map scale of 1:15,840 Producer defined SOURCE Source of imagery used in analysis Producer defined BW Orthorectified aerial images Black and white aerial images acquired by Map Inc. on Sept. 11, 12, 14, 15, 1998. Contracted by USGS. Orthorectified through process of rubbersheeting by Michelle Manly, University of North Dakota. Prints, negatives and diapositives stored at USGS office, West Glacier, MT Producer defined COMMENT Items of note pertaining to features or imagery issues Producer defined 4 main fingers of the terminus were edited to match 2003 gps mapping Unknown Producer defined finger is rock glacier Unknown Producer defined image slightly offset Unknown Producer defined no comment no comment regarding imagery use or margin delineation Producer defined some image offset Unknown Producer defined Shape_Leng Perimeter of glacier polygon Producer defined 661.900394958 22877.2408198 meters Area1998 Area glacier in 1998 Producer defined 23756.51 1846232.52 meters squared OWNERSHIP Federal land designation for the location of the glacier Producer defined Flathead National Forest Flathead National Forest, Department of Agriculture Producer defined Glacier National Park Glacier National Park, Department of Interior Producer defined OBJECTID Internal feature number Producer defined 1 39 The entity and attribute information provided here describes the tabular data associated with the data set. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data set. The entity and attribute information was generated by the individual and/or agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information. U.S. Geological Survey ScienceBase Mailing and Physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov Distributor assumes no liability for misuse of data. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Vector Digital Data Set (Polygon) https://dx.doi.org/10.5066/F7P26WB1 None. No fees are applicable for obtaining the data set. 20200826 Lisa A McKeon U.S. Geological Survey Physical Scientist Mailing Address

PO Box 169

West Glacier MT 59936 USA 406-888-7924 406-888-7923 lisa_mckeon@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998