Draw Prisms
Function Name:
This function must be used to draw the graphs of the various measured and derived attributes verses time. With this function you can choose which prisms are to be drawn and which attributes are to be drawn. The graphs of all attributes are depicted as simple line graphs with labelling, colour and a legend used to aid in distinguishing one line graph from another.
It is possible to draw as many line graphs for multiple prisms and multiple attributes at a time. This can be useful to examine the correlation between displacement, velocity and acceleration to aid in the examination of the results. The X and Y scales are chosen so that all the data selected for display can be viewed on the one set of axes. Consequently you may find that displaying the X, Y or Z values with velocities or accelerations of any of these attributes produces meaningless graphs.
Typically, the best results will be obtained by displaying the delta (change in) values and velocities or accelerations of selected attributes.
Choose Survey > Survey database > Stability monitoringand then Display prism graph to invoke the function.
Fields on the Draw monitoring prisms form
X Axis
The measured attribute which will be used for the X axis of the graph must be chosen. To obtain attribute value verses time graphs the prism_date attribute must be chosen. Under certain circumstances you may find it useful to use a different attribute for the X Axis.
Y Axis values and Colour
It is possible to draw multiple line graphs for each prism with each line graph representing a different measured or derived attribute. To aid in distinguishing the graph of one attribute from another you may choose different colours for the display of each of the different attributes.
You will find that having more than two or three different attributes graphed at the same time can prove unhelpful especially when the range of values of the different attributes being displayed vary by an order of magnitude or more. This will tend to flatten the line graphs making it difficult to assess trends such as increasing velocities which are good predictors of impending failure.
Choose prisms to be displayed
The SELECT PRISMS function may have resulted in the data for more than one prism being retrieved from the prism table for analysis. If this is so then displaying line graphs for all prisms may make it difficult to examine for trends which may indicate impending failure. At other times however it may be useful to display the line graphs for some or all prisms to see such trends.
Choose which prisms are to have line graphs displayed by entering either:
- first prism
Only lines graphs for the first prism extracted from the prism table will be displayed.
- select prisms
A list of all the Prism Ids which have been extracted from the prism table is displayed in a scrolling region. You may choose which prisms are to have line graphs displayed by entering 'Y' or 'N' appropriately to indicate if line graphs are required or not.
- all prisms
Line graphs for all selected prisms will be displayed.
Complete the DRAW MONITORING PRISMS form and choose Apply to draw the line graphs of the selected attribute values for the selected prisms.