Calculate Menu

This menu option for a map window allows calculation of various parameters and graphics.

  • Area: outline the desired area. You do not have to close the area. Select either with stream or point digitizing, whichever you have active.
  •   Distance: double click on points and get the distance between them and the cumulative distance. This option remains active until you decline to add another point to the line.
  • Volume:
  • Geodetic bearing
  • Bearing: calculate bearing (angle) between two points using the Vincenty (1975) geodetic algorithm. This will use a geographic angle (from true north).  The line and bearing of the two ends will be plotted on the map.
  • Point coordinates
  • Slopes
  • Elevations
  • Ridges/valleys
  • Spires and pits 
  • Roads
  • Building edges/roofs (requires DSM as current grid)
  • Walls
  • Peak/island area
  • Profiles
    • Stream: plot longitudinal profile of a stream valley by clicking on points.
    • Extract points: Digitize the profile, and then pick the point separation interval, and whether you want the points to be exactly on DEM grid points or interpolated between them. Creates a database.
  • Area of single color: This will be done at screen resolution.  If the map covers a large area with a geographic projection, this will be approximate.
  • DEM/Grid area: uses the DEM or grid, with the potentially variable spacing in the x direction.  This will use all non-missing pixels in the grid, so if you want to find areas meeting a particular criterion, edit the grid first and mark missing points that do not match your criteria.
  • Point parameters 
  • Offset: enter a distance and up to 5 bearings, and the computer will plot the location relative to a starting point that you select.
  • Rhumb line
  • Drainage
  • Oceanography
  • Climograph
  • Age from depth (MGT): calculate age from the depth. This assumes normal seafloor subsidence, with a ridge depth of 2.5 km. It will give approximate results, but will not be valid on land, continental shelves or slopes, or near trenches. After selecting this option, the calculated age will appear at the bottom of the map when you roam with the mouse until you select another option that employs the mouse.
  • DEM Grid:
  • Derivative grid
  • Topographic grain
  • Intervisibility
  • Flight coverage
  • Map window corners--get a text box with the map window corners, and the center.
  • Point categories
  • Image palette
  • NLCD
  • PLSS
    • PLSS from Lat/Long--click on map, and get the PLSS location
    • PLSS from Lat/Long keyboard entry
    • Lat/Long from PLSS
  • US properties  (requires that shapefiles be correctly located)
    • Geology
    • 7' Quad Names
    • Counties
  • Roaming Z values from 2d grid: pick a second open grid, and while you roam, its z value will appear in in the status bar.  This will show only that single DEM, instead of all DEMs (which might not fit if you enough open and a small monitor).
  • Where is? (keyboard)
  • RGB values
  • Max/mean/min grids from point data:
  • Vegetation density layers
  • Contours shapefile (GDAL): this will be in the temp directory; save elsewhere before closing the program.
  • Abort current operation

Last revision 11/26/2017