2000 Snow Survey for Green Lakes Valley, Niwot Ridge LTER, Colorado

Yearly snow surveys were conducted in the Green Lakes Valley in the City of Boulder Watershed at the estimated peak of snowpack in late spring. Over a period of several days, surveying teams (1 to several people) traversed valley slopes measuring snow depth with avalanche probes. Locations of each depth measurement were recorded as waypoints in Garmin hand-held GPS units (eTrex Legend and eTrex Legend H models). Snow depths were recorded on standardized field sheets along with dates, recorder names, waypoint numbers, and comments. GPS locations were downloaded as text files from Garmin units using Topo! software, specifying NAD83 for surveys conducted after 2009. Download files contained waypoint number, latitude, longitude, date, and elevation. Each file was imported into a Microsoft Excel spreadsheet and snow depths corresponding to waypoints were entered manually from field sheets. Shapefiles were constructed in ArcInfo/ArcGIS from dbf files generated either directly from Excel spreadsheets (before 2008) or after importing into Microsoft Access and then exporting as dbfs. All shapefiles are provided in a UTM zone 13 projection and NAD83 horizontal datum. NOTE: This EML metadata file does not contain important geospatial data processing information. Before using any NWT LTER geospatial data read the arcgis metadata XML file in either ISO or FGDC compliant format, using ArcGIS software (ArcCatalog > description), or by viewing the .xml file provided with the geospatial dataset.本数据集的年度积雪调查于晚春积雪预估峰值时段，在博尔德市流域（City of Boulder Watershed）的绿湖谷（Green Lakes Valley）开展。 调查团队由1至数人组成，于多日内沿山谷坡面行进，使用雪崩探杆开展积雪深度测量。 每次积雪深度测量的位置以航点形式，记录于佳明（Garmin）手持GPS设备（型号为eTrex Legend与eTrex Legend H）中。 积雪深度与测量日期、记录人员姓名、航点编号及备注信息，一并记录于标准化野外记录表中。 2009年后的调查采用NAD83坐标系，使用Topo!软件从Garmin设备中导出GPS位置的文本文件。 导出的文本文件包含航点编号、纬度、经度、测量日期与海拔信息。 将每个导出文件导入Microsoft Excel电子表格，随后从野外记录表中手动录入对应航点的积雪深度数据。 空间数据以ArcInfo/ArcGIS软件构建形状文件（shapefile），其源dbf文件可直接由2008年前的Excel电子表格生成，或经导入Microsoft Access后导出为dbf文件。 所有形状文件均采用UTM 13带投影与NAD83水平基准面。 注意：本EML元数据文件未包含重要的地理空间数据处理信息。 在使用任何NWT LTER的地理空间数据前，请使用ArcGIS软件（通过ArcCatalog > 描述菜单）查看符合ISO或FGDC格式的ArcGIS元数据XML文件，或直接查阅随地理空间数据集附带的.xml文件。