Ezigrade (version 2)

Grid

 
This option strips out the existing points used within a section and replaces them with points in a rectangular grid lying along the section axes. You would normally only do this option when you are sure of the section layouts. This is because the original survey points are deleted from the job and replaced with the points on an array. Ezigrade allows you to go back and re-instate the original job. Do this from the File -> Restore (Archive) function.
 
After using this option we would expect that you are using the Triangle based grading.
 
There are a number of pro's and con's when using this routine:
 

Advantages:

 
  • Having equally spaced points lets the grading algorithm work equally well everywhere in the job rather than just where the points were surveyed. It can lead to lower volumes.
  • Some outlier type designs needed gridded points to work. An example is a section that has variable main slope but needs a zero cross slope. Points need to lie across the section so changes of main slope can be achieved while achieving zero cross slope.
  • Sections with lots of points can be cut down so that grading algorithm can work faster.
  • Sections with only a few points in it can have more added to get a proper design.
  • Some jobs that have lots of points in rows but the rows a long way apart; can be designed with lower volumes.

Disadvantages:

 
  • We are now working on a gridded representation of the original natural surface. We can be losing original features etc
  • Volumes are now reported back to the gridded natural surface points - not the original picked up points
 
 
As noted above. We suggest that you can create side-by-side designs using both original points and gridded points to gain an understanding when this option is worthwhile and when not to bother. In general the closer the gridded points are together the better the final design etc. However this does come at the expense of greater processing time.
 
A good way to test is to have; the original job. Create a copy and put in a coarse grid. Work on this until you are happy. You can then go back and create another copy from the original and create a finer grid.
 
Here are a couple of examples that show when to use and not use this function.
 
This is a sample where gridding the section does make some sense. You can see that there are only a few points across the job. This gives a segmented looking design. We should be able to get a smoother 3D surface with more points. As a reference this has an indicative value of 167 meters cubed per hectare.
 
 
This is the job after we grid it. You will notice that the grading algorithm has been able to create a design between the original picked up data points. Also the smoothing algorithm has more data points to use within the smoothing distance to create a smoother surface. In this case we could reduce the smoothing distance further as well to reduce the volumes. In this case we have reported volume of 139 meters cubed / hectare. However you need to be aware that this is to the new gridded data surface not the original. The volume to the original will be marginally greater than this value.
 
 
For further details refer to tutorial further on in the manual.
 
 
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