Leveling Data Format

Leveling Data

FGDC Metadata

The Highway 395 route was surveyed in 1932, 1957, 1975, 1980, each summer from 1982 to 1988, and again in 1992, 1995 and 1997.
Complete leveling of the caldera occurred each summer from 1982 to 1986, and in 1988 and 1992. The benchmark C916 is the elevation datum (2072.54196 m) for all the leveling surveys.

The leveling surveys have been run to standards equal to those required for second-order, class II levels or first-order, class II levels. The standard error for each elevation difference can be taken to be 3 mm/L^1/2, where L is the distance between benchmarks in km.
Leveling observations were corrected for rod scale and temperature, level collimation, and for astronomic, refraction and magnetic effects. Leveling surveys were not referenced to the NAVD88 datum because the U.S. Geological Survey was only interested in monitoring relative elevation changes within the caldera.

The data are provided in ASCII XYZ files, and ArcView shapefiles format.

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ASCII format files

Directory	MonitoringData/Geodetic/Leveling/SpreadsheetFormatData
File	MAMMOTH2g.txt	complete leveling dat set (all stations from 1932 ro 1997)

Map projection	Geographic
Datum	NAD27
Units	DMS
Z_Units [elevation]	Meters

ArcView shapefiles format

Data are provided in ArcView shapefiles that can be used in a number of GIS and visualization software packages.

Directory	MonitoringData/Geodetic/Leveling

Shapefiles (.shp)
antVLoop	benchmarks and elevations along the Little Antelope Valley leveling route
bigLoop	benchmarks and elevations along the Owens River Rd leveling route
hw202Loop	benchmarks and elevations along CA HWY 203 leveling route
hw395Loop	benchmarks and elevations along HWY 395 leveling route
longVLoop	benchmarks and elevations along a leveling route spanning the Long Valley plane
otherLoop	benchmarks and elevations along HWY 395 leveling route
smalLoop	benchmarks and elevations along leveling routes monitoring the resurgent domes

Map projection	UTM
Datum	NAD27
Units	Meters

Download files to desktop
1. Go to the MonitoringData/Geodetic/Leveling folder to download the data

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