Preparing a design often requires that elevation data is imported from an external file. In some cases (from some government websites for example) the data you obtain may cover a much larger area than is required for your particular design.
The Trim Elevations tool enables contours to be trimmed to a specified polygon. Contours, and spot heights, may then be deleted within or outside the lasso.
Advantages of reducing the quantity of elevation data in this way are:-
- In IRRICAD Pro Version 10.5 and older there is a limit on the number of contour segments that can be processed. Decreasing the number of contour segments by trimming the elevations, so that they just span the hydraulic design area, will help to comply with this limit. Note that Pro Version 11, due for release shortly, can handle an unlimited number of contour segments.
- Decreasing the number of contour segments will increase the speed of redrawing, and interpolation of, elevation data.
- Increasing the accuracy and performance of the Digital Elevation Model (DEM). The DEM grid is calculated over the area spanned by the elevation data and therefore a larger area of contours requires a larger DEM grid size to maintain the same accuracy. The calculations for DEMs with large grid sizes can take some time.
- Zoom All will zoom only to the extents of your irrigation design area.
Trim Elevations is accessed from the Tools menu, instructions for its use may be found in the Tool and Command manual under Help|Help Topics.
We hope you have found this helpful. If you have a tip you would like to share, please email your tip to Support@IRRICAD.com
The Trim Elevations tool enables contours to be trimmed to a specified polygon. Contours, and spot heights, may then be deleted within or outside the lasso.
Advantages of reducing the quantity of elevation data in this way are:-
- In IRRICAD Pro Version 10.5 and older there is a limit on the number of contour segments that can be processed. Decreasing the number of contour segments by trimming the elevations, so that they just span the hydraulic design area, will help to comply with this limit. Note that Pro Version 11, due for release shortly, can handle an unlimited number of contour segments.
- Decreasing the number of contour segments will increase the speed of redrawing, and interpolation of, elevation data.
- Increasing the accuracy and performance of the Digital Elevation Model (DEM). The DEM grid is calculated over the area spanned by the elevation data and therefore a larger area of contours requires a larger DEM grid size to maintain the same accuracy. The calculations for DEMs with large grid sizes can take some time.
- Zoom All will zoom only to the extents of your irrigation design area.
Trim Elevations is accessed from the Tools menu, instructions for its use may be found in the Tool and Command manual under Help|Help Topics.
We hope you have found this helpful. If you have a tip you would like to share, please email your tip to Support@IRRICAD.com