This tutorial is a brief introduction describing how to install and use uniDEM.
It includes the description of how to load and view an elevation model in uniDEM,
and ancillary data overlays to the elevation model and how to zoom/pan and toggle between 2D and 3D views.
The sample data used in this lesson is a Digital Terrain Model with a pixel spacing of 1 arc-second (30 meters) -
called NakedEarth - a 1° x 1 ° geotile covering Seattle, WA, USA.
Prior to commencing this lesson, please download the sample DTM and ancillary data:
Right click NakedEarth_N47W123 in the Table of Contents (TOC) on the left and select Check All
The DEM will be displayed in the data view window
Note: DEM (DEM) in the dataset listed in the Table of Contents is bold. This means it is the Active Dataset.
The Active Dataset holds the DEM that will be edited.
When complete, uniDEM should display a colorized shaded relief of the DEM looking from the top down (Bird's-Eye View):
This section shows how to interact with the data in 2D and 3D.
Pan and Zoom
Click into Data View
Pan: left click while moving mouse over the window
Zoom: scroll with the mouse wheel
Rotate and Tilt
Click into Data View
Rotate: right click and move mouse left/right
Tilt: right click and move mouse up/down
Make a Selection
Selections are the first step to editing DEM data. Selections can be performed on any loaded dataset
and edits are then applied within the Active Dataset.
Select All
Press Crtl-A to select the whole dataset
Press Esc to clear the selection
Collect a Polygon
Press P to enable the Polygon collection tool
Hold down Shift+Left-Click key and left click a location over the DEM
Click more points and a polygon will be drawn
Press Shift+Backspace and the last point drawn will be removed
Pres Esc to clear the selection
There are many selection methods available including Flood filling, vector to raster and filtering techniques.
Change Viewing Orientation
North-up: Press N
Top-Down: Press T
2D (Orthographic): Press 2
3D: Press 3
Vertical Exaggeration
To view the terrain in 3D it might be helpful to display the elevation model vertically exaggerated.
uniDEM offers the following exaggeration factors: 1x, 2x, 4x, 8x, 16x, 32x
Within the Options top click Vert. Exag. and select the desired exaggeration factor
The datasets can be viewed in multiple data views simultaneously.
The views can be linked so they move together or unlinked allowing for multiple zoom and view settings.
Press Ctrl-N 3 times to create a total of four data views
Press Ctrl-T to tile (organize) the data views
Click top right data view
Right click the AW3D30_N47W123 dataset in the TOC and click Check All
Right click the SWBD_N47W123 dataset in the TOC and click Check All
Click bottom left data view
Right click the n47_w123_1arc_v3 dataset in the TOC and click Check All
Right click the NHDWaterbody dataset in the TOC and click Check All
Click bottom right data view
Right click the NakedEarth_N47W123 dataset in the TOC and click Check All
Right click the SeattleNaip dataset in the TOC and click Check All
Right click the SeattleNaip dataset in the TOC and click Fit To Window
Note: The layer NakedEarth_N47W123 named DEM (DEM) listed in the Table of Contents is bold.
This means this is the Active Dataset. The active dataset holds the DEM that will be edited.
Adjust Data Views
uniDEM can present many different shaded relief colors.
By default DEM data is depicted as a colorized shaded relief with no vertical exaggeration.
Click top left data view
Press H to display the gray scaled shaded relief
Within the Home tab adjust Sensity to 3.0 to "sharpen" the shaded relief
Click top right data view
Press R and draw a rectangle by using Shift + Left click
Press B to calibrate the elevation range of the shaded relief to the range of elevations within the rectangle
Click bottom left data view
Within the Home tab change the Color Scheme from Jet to Topo
Press B to calibrate the elevation range of the shaded relief to the range of elevations within the rectangle
Click bottom right data view
Within the Home tab change the Scope from Global to Custom