GSMNP GPS peak survey

The Great Smoky Mountains National Park is conducting a GPS elevation survey of the park's peaks. Under the direction of Park GIS specialist, Tom Colson, volunteers are toting the GPS with its antenna bipod into the high country and spending four to five hours with the unit as it acquires GPS data. With post-processing (and an unobstructed view of the sky), the survey is providing location and elevation data accurate to 5 cm. See call for volunteers and Yahoo group (members only) Some survey trip reports: West Point | Big Butt | Rich Mtn

Here are some unofficial preliminary results.

• GSMNP LiDAR (noted as 1.5m) is based on preliminary data from spring 2011 survey with 18cm vertical accuracy, see TN lidar area on google map. Other elevations provided by Tom Colson, GSMNP.
• GPS survey is ongoing and data is preliminary. Survey utilizes Trimble TRM 5800 (L1/L2) and OPUS post-processing with CORS base stations. Error is the OPUS error in the vertical component (see OPUS accuracy). OPUS solutions are initially rapid, after about 14 days a precise solution is available from actual orbit data.
• in the USGS column, BE indicates bare-earth LiDAR high point from 2009 NC LiDAR survey (vertical accuracy 10-25cm RMSE). 3m (1/9th arc second) indicates USGS data (usually based on NC LiDAR) 10m indicates older USGS digital elevation data based on photgrammetric data that is typically used in constructing the USGS topo maps

Measuring the elevation of a mountain peak is tricky no matter the technology. In the forested summits of the east, it is difficult for LiDAR aerial scans to get bare-earth returns (see Big Cataloochee bare earth LiDAR). GPS ground surveys may not have a clear view of the sky. Any ground survey is faced with actually determining where the highest bump is on some of the "rounded" peaks (Big Cataloochee, Mount Sequoyah). Often USGS survey markers are seated in nearby rocks and are not at the "high point" (see further discussion on USGS surveys). And finally, error is sometimes introduced by the human element, see discussion on the phantom peak of Big Cataloochee.

More info

• Smokies google map landforms, trails, camp sites, eleavtion query (LiDAR)
• USGS seamless elevation server
• TN Smokies LiDAR survey and survey area on Google map
• GSMNP GPS info and mobile phone GSMNP topo maps
• NC flood plain mapping LiDAR data with 25cm vertical accuracy, download bare-earth or NC state-plane data. Most of this data has been incoporated by USGS in their seamless DEM data.
• NC LiDAR: bare earth returns for Big Cataloochee and the phantom peak
• intro to LiDAR and digital elevation data
• gaps in GSMNP LiDAR surveys can be seen on National Map viewer, enable the "Elevation Availability" layer in the national map viewer and enable the NED 3m box
• GPS handbook and Trimble's GPS tutorial
• NGS benchmarks data sheets and accuracy terms VERTCON
• Trimble 5800 user guide
• Trimble GPS survey planning tool satellite visibilities, *DOP
• vertical datums NGVD 29 and NAVD 88 and VERTCON and converter
• NGS survey marker and survey marker accuracy terms
• a list of some of the benchmarks appearing on Smokies topos and visits to some of Smokies benchmarks and map Mystery, many of the smokies benchmarks do not have NGS datasheets?
• 12 peaks over 6000' in the Smokies (with prominence of at least 200')
• Great Smoky Mountain peaks of 5000' and higher with at least 160' of prominence on Google map
• GPS'n the Smokies trails
• Appalachian Trail elevation profile along the Smokies
• TN LiDAR survey map and data, and 2014-2018 LiDAR survey business plan and technical specs (12.5 cm veritcal RMSE)
• GSMNP GIS stream mappers project, call for volunteers
• News Sentinel article on Smokies LiDAR 12/10/12
• consumer GPS accuracy spot checks along the Smokies crest
• Tennessee county high points
• USGS NED 3D elevation program