Determining the output parameters

Import the source for generating the DEM with one of the following:

After importing the source for generating the digital elevation model (DEM), you determine the parameters of the DEM output.

  1. On the Define Output DEM File window in the Output DEM box, type the path where you want to save the DEM or click Select to determine the path.
  2. Click one of the following:
    • Elevation Source Area to generate a DEM that covers the area where elevation data exists (recommended).
    • Photo Extents to generate a DEM that covers the extents of all the images in the project. This is useful when you want the DEM to cover the images being orthorectified, but extrapolating beyond the elevation source area can cause significant errors in your project.
  3. In the Background elevation box, type the value to represent the background or 'No Data' pixels in the DEM.
  4. Three parameters determine the final output of the DEM: the size, the resolution, and the bounds of the DEM. You can specify two out of the three, and OrthoEngine with calculate the third:
    • To set the size and bounds for the DEM, click Use pixels/lines and bounds in the list.
    • To set the size and resolution for the DEM, click Use pixels/lines and resolution in the list.
    • To set the bounds and resolution for the DEM, click Use bounds and resolution in the list.
  5. Depending on which option you selected in step 4, set the two parameters of your choice:
    • To set the Size: Type the number of pixels in the Pixel box and type the number of lines in the Lines box to determine the size of the DEM.
    • To set the Resolution: Type the x and y dimensions of the pixel size in the corresponding X and Y boxes.
    • To set the Bounds: In the Bounds list, click Geocoded to enter the bounds in georeferenced units or click Geographic to use Longitude/Latitude units. In the Upper left boxes, type the coordinates of the upper-left corner of the DEM. In the Lower right boxes, type the coordinates of the lower-right corner of the DEM.
  6. Click Generate DEM.
  7. If you are generating a DEM from vectors, you must select an interpolation method. Select one of the following methods in the DEM Generation Method window:
    • Natural Neighbor Interpolation to use the Natural Neighbor algorithm to interpolate the DEM from points. It is recommended for files that contain sparsely distributed or unevenly distributed points since it performs a more intelligent calculation than Finite Difference. However, it is not recommended for files that contain a large number of points since the calculations required will take considerable more time to process.
    • Finite Difference to use the Distance Transform and Finite Difference algorithms to interpolate the DEM from points. It is recommended for files that contain evenly distributed points. It can rapidly process an unlimited number of points.
      1. In the No of Iteration list, type the maximum number of times that the DEM is smoothed.
      2. In the Tolerance box, type the minimum difference in value required during smoothing to warrant another application.
      3. Click Accept.
  8. If you are generating a DEM from contours, specify the following in the Iteration Values window:
    1. In the No of Iteration list, type the maximum number of times that the DEM is smoothed.
    2. In the Tolerance box, type the minimum difference in value required during smoothing to warrant another application.
    3. Click Accept.
  9. View the DEM. If it is satisfactory, click Accept DEM in the Define Output DEM File window.
Parent topic: Generating digital elevation models
Previous topic: Understanding the interpolation methods for vectors
Next topic: Creating a digital elevation model from a stereo pair

© PCI Geomatics Enterprises, Inc.®, 2026. All rights reserved.