TLDR: for working with LiDAR elevations
	https://apps.nationalmap.gov/3depdem/
      is a lot easier than 
	https://apps.nationalmap.gov/viewer/

      Thanks go to Jake Cramer for showing me this better site.


Discussion:
	A long standing problem with the LiDAR data on
	apps.nationalmap.gov/viewer is the difficulty in
	establishing contour elevations, and that point
	elevation queries do not return LiDAR elevations.
	These issues are not present on

		https://apps.nationalmap.gov/3depdem/

Example:
	We investigate the prominence of The Nose, VT
		https://listsofjohn.com/peak/102560

	The first attachment shows the LiDAR contours
	for this feature with nationalmap.gov/viewer

	Note that the contour interval is not shown, and that
	elevation queries on a given contour vary by
	15 feet, because older non LiDAR elevations are being
	given.

	The second attachment shows the same area with
	https://apps.nationalmap.gov/3depdem/
	We have set the contour interval to 1 meter, and can
	now count 63 contours of 1 meter (206 feet) from
	the top of the Nose to the key saddle
	to the north. In addition we can use the Identify 
	Tool ("i" icon) to query elevations, and LiDAR values
	are returned, in this case 4063 feet for the top of
	The Nose.
	Note that contours are enabled by the 7th icon from
	the top, on the left margin of the 3depdem viewer. 

Availability:
	Not all areas of the country have LiDAR coverage.
	On way to determine this in your area of interest
	is to zoom in until the scale at lower left
	shows 100 meters. (third attachment).
	Areas with LiDAR coverage show fine details like road
	cuts. Areas without this coverage are much coarser,
	like the Northeast part of the attached image.

Navigation:
	The LiDAR shading alone is not very helpful for
	navigating to a particular location.
	The Transparency Slider (9th icon, balance scales)
	can be set to 50% or more to allow basemaps to aid with
	navigation. Basemaps are selected with the Basemap
	Gallery icon (four squares, under the "+" and "-" icons)