Overview
MobileMap uses Check Cruise Rules to generate a check cruise scores at the tree and plot level. Check cruise rules are maintained in the table called Check Rules. Check cruise rules compare values between original cruise plot, tree, or log attributes and the corresponding check cruise (audit) plot, tree, or log attributes.
When creating Check Cruise Rules, users define a test and assign a deduction to be applied if the test fails. An example is “if the DBH of the measure tree is off by more than 1 inch, then deduct 3 points”. When Check Cruise Rules are violated, the deduction amount is subtracted from the individual tree’s score. The sum of the tree level deductions is then calculated for the plot on which those trees were measured. Finally, a plot level score is calculated using the following equation
Plot level check score = 100 - (the sum of the tree level deductions + the sum of the plot-level deductions)
Example
As an example, consider a plot with 5 trees which has been check cruised. The first 3 trees are a complete match between the measure tree values and the check cruise tree values. Tree 4 has an incorrect Species. Tree 5 has a height that is 20% higher than the check cruise tree and a DBH that is 1 inch smaller than the check cruise tree. At the plot level, the check cruiser recorded a different Plot Condition then the original cruiser.
The Check Cruise Rules include the following rules
If Species is not equal then deduct 4 points
If Height is not within 10% then deduct 2 points
If DBH is not within 1 inch then deduct 3 points
If plot condition is not equal then deduct 2 points
When the check score is calculated, trees 1-3 have a deduction of 0, tree 4 has a deduction of 4 points and tree 5 has a deduction of 5 points (2 for the height and 3 for the DBH). The plot has a deduction of 9 points from the trees and another 2 points due to incorrect plot condition. This results in a total deduction of 11 points for the plot, which is used to generate a plot-level check cruise score of 89.
Managing Check Cruise Rules
In order to assist with the management of Check Cruise Rules, InventoryManager provides a dedicated interface for creating and editing Check Cruise Rules. This user interface is only available to users with the ‘Site Manager’, ‘Data Manager’ or ‘Administrator’ roles in InventoryManager.
To access the Check Cruise Rules user interface, select the ‘Check Rules’ item on the administrator interface in the upper left corner of the appropriate map.
The screenshot below shows this user interface in a typical InventoryManager implementation.
Following the workflow of the user interface above, the process for creating a new check cruise rule is the following:
Give the Check Cruise Rule a short, concise name that can be used when understanding the deductions that are applied. This name will be included in the excel report and written back to the Plots layer
Type the rule name (e.g., ‘Species mismatch’) in the Rule Name text box
Select the layer that the rule should act upon (typically Plots or Trees)
Click on the desired layer in the dropdown list
Select the attribute Field that will be assessed
Click on the desired field (e.g., DBH or Height) in the Field dropdown list
There are two special cases that can be selected in addition to the data model fields in the selected layer
MAX_DEDUCTION - when this option is used, it sets the maximum amount of points that can be deducted at the Tree or Plot level. This is useful when a single tree has a large number of individual errors and would disproportionately inflate the deductions on the plot. A typical value for this option is 10. This means that even if a Species deduction and a DBH deduction and a height deduction are present on this tree and would sum to a 12 point deduction, the tree’s deduction would max out at 10 if this option was used.
ADDED_MISSING_TREE - when this option is used on the Trees layer, it sets the value that should be used when a tree was added or is missing. Typically this is set to the same value as MAX_DEDUCTION but it is sometimes set to an even higher value (e.g., 15).
Select the Operator that should be used in the test
Click on the desired operator in the Operator dropdown list, paying special attention to the difference between < and <= or > and >=
Type the Value that should be used for the test. For numerical fields, the value is the amount by which the measured tree value and the check cruise tree value can differ by and not accrue a deduction.
Check Cruise Rules will compare the absolute difference of values for numerical fields by default. For example, if the standard tree was 50 feet in height and the check cruise tree was 55 feet in height, this will be the same as if the standard tree was 55 feet in height and the check cruise tree was 50 feet in height.
For percent comparisons, use '%' (without the single quotes). For example, to set the value to a 5 percent difference, use '%5' as the input to the Value box.
Leave Value empty when using operators "=" or "!=", as this is testing for identical values.
For floating point data, use < or > and a small threshold to avoid floating point rounding issues.
For Stands and Plots, check cruise scoring works within a single feature, rather than comparing 2 features as it does for Trees.
Check cruise rules can assess single fields or compare values between two fields of the same type within that feature.
Use "Null" (without quotes) for no value and use field name in curly brackets for field value (e.g., "{DBH}" - without quotes)
Input the Deduction.
Type the amount that should be deducted from the Check Cruise score if the two field differ by the amount in the Value, or if they are different in the case of categorical attributes (non-floating-point attributes) in the Deduction box.