|Tennessee county high points|
In the table, click on the county name to view the Google map and get a list of maps for that point. At the bottom of the table are waypoint files for uploading to your GPS. Latitude and longitude are in the WGS84 datum and extrapolated from USGS 7.5' topo maps or provided by the DEM data.
Andy writes: White spot elevation 2 miles east of DeRossett 2,009 DeRossett 16 areas within 2 miles of 2009 spot elevation 2,000+ DeRossett 9 areas within 1 1/4 miles of Stringtown 2,000+ DeRossettWe have used 10m USGS/NASA digital elevation data (quad/UTM DEMs or better seamless server) to resolve the multi high point counties. For White county, the 10m DEM shows the high point (35.87875 -85.31523) at 2010'. (See Google map with DEM grid over candidates -- zoom out to see all areas.) Another candidate, was the contour with the 2009' spot elevation, but the DEM data reported only 2005.9 for the high point in that contour.
As another example, see the 10m DEM grid over the two candidate areas for Sullivan county. The Rutherford county high points illustrate points on the county line -- digital high point 1366.8' near Brown Cemetery. Or is that in the adjacent county, how accurate is the line on the topo map? The 10m DEM high point might actually be 1366.7' near Harrold Cemetery. From the 2004 LiDAR survey of Rutherford county, the high point is 1366' at Harrold Cemetery 35.71839,-86.23124. The 10m DEM data revealed a high point (35.21757 -89.7475) for Shelby county that was not on Andy's list -- and at 436'. Tom Owen reports this is a man-made (overpass), so we have not listed it as the high point. On the other hand, we did find some bad DEM (or topo?) data in the Dyersburg quad in Dyer county, TN. Topo map has a couple of 500 and 510 contours and one 515 spot elevation. The max elevation from the 10m DEM for the quad is only 476' (at the 515 spot elevation). See visual evidence. The DEM data from seamless server has the spot elevation at 492'. Looking at the satellite image, it's possible the high point has been bull-dozed down.
Henry and Lake county had no quad-based 10m DEM data for the areas of interest, but USGS seamless server had 3m DEM data for both Henry and Lake county. (Example: Lake County, view the map, and see the new HP is the southwest cluster of red +'s. If you zoom in and switch to satellite view, you'll see they probably built a hill for the water tank!) This 3m data is based on LiDAR (see bullet list below), but LiDAR elevation data for TN is presently only available for a few areas: Rutherford county (2004), Hamilton County, Davidson County, City of Franklin, Smoky Mountain, along the Mississippi and the NC boundary (see map). TN GIS in 2011 developed a LiDAR business plan and technical specs for conducting TN LiDAR survey (18 cm veritcal RMSE) at $10.4 million (2014-2018).
Thunderhead Mountain, Blount County high point, has a USGS benchmark disk that reports elevation of 5527' (no USGS datasheet?). The USGS DEM data lists the Thunderhead high point as 5533.7' at 35.56862,-83.70622. The recent NC LiDAR survey reports high point of 5524.75' at 35.56862,-83.70622 (bare earth).
SRTM data (30m) is also available from earthexplorer.usgs.gov and is more recent (2000), but is based on "first-return" data and may have inaccuracies. (Example: cohp'ers visiting Bryson Mtn (Claiborne county) noted that summit (3200') had been reduced by stripmining. Neither the 30m or 10m DEM data revealed this, but the SRTM data did (3117'), see map or use the track elevation profile on the cohp google map.) I am now using the seamless server for the source of elevation data. Also Google Earth seems to have fairly accurate elevation data (10m DEM or 30m SRTM?), and we have a coarse (30m SRTM) elevation profile tool on our Google high points map along with 10m (and in some cases 3m LiDAR) spot elevations.
Sevier county has the maximum elevation differential -- Clingmans Dome (6643') to the French Broad River (850'). The highest point in TN is Clingmans Dome at 6,643', and the lowest point is 178' along the Mississippi. (Elevation profile from Memphis to Clingman's Dome.) The Tennessee county high points have one "twofer", a single high point that serves two counties: Marion and Sequatchie at Lockhart. Anderson and Campbell county mostly share a high point, though the Cross Mountain benchmark (high point) is in Campbell county. Here is a nice article from the Tennessee Conservationist magazine on Tennessee's high points.
|topo contours||1/2 contour|
|spot elevation||1/3 contour|
For reference, here are Andy's original TN county high point areas, courtesy of Tom Owen, and on Google map (includes new additions in Shelby and Lake County), and tnahps.gpx and tnahps.kmz. Andy has a demo Google map for various US county high points, includes gpx and kml data and link to trip reports, derived from Adam's cohp.org.
visits since 12/10/04
Fri, 02 Nov 2012 12:36:37 -0400