GEM4D Version 1.8.2.1 is a small update with three additions:
PrisVec now correctly handles different date formats such as UK (Day/Month/Year) and US (Month/Day/Year);
PPV can be shown as mm/s or m/s;
Object center coordinates can be exported as a CSV-file.
I accidentally removed some of the columns from "Ribbon => Marker => Marker actions => Distance => Add grid distance column" in the previous version, which is used by many open pits for toe and crest reconciliation - apologies for that.
New functionality
"Ribbon => External => Instrumentation => PrisVec" now supports both Day/Month/Year (UK) and Month/Day/Year (US).
When calculating PPV with "Top toolbar => Colour palette 2 => Colour on PPV from coordinate", the result can now be expressed in m/s and mm/s, and the input triangulation can be in meter or feet.
Export object center coordinates s with "Ribbon => Mesh => Export files => Mesh info as CSV => Individual object centers".
Bug fixes
"Ribbon => Marker => Marker actions => Distance => Add grid distance column" always exported three distances from the markers for each object: XYZ, XY and Z. I removed the XY and Z export columns in a previous version, forgetting that those columns are used in some analyses, apologies for that - fixed.
GEM4D crashed when the bottom panel was hidden and information written to the information text box to the bottom-right - fixed.
Discussion: Prism data in GEM4D
Prism data can be managed in one of two ways:
Scalar displacements; thus prism movements without any sense of direction.
Vector displacements; thus prism movements from two coordinates using PrisVec.
NOTE 1: For the colour coding of meshes, the meshes should be sub-divided to represent colour detail, as the colouring is only occurring at the mesh vertices, and the values between vertices interpolated. Sub-divide the pit mesh with "Top toolbar => Toolbox 1 => Sub-divide lines/polys - split on size" and select a division size. The division size depends on the number of prisms available, resolution required, and time available - a small division value for a large mesh will increase the mesh size significantly.
NOTE 2: Double clicking on the top ribbon menu items toggles the ribbon visibility. If you thus find the ribbon hidden, just double click on any top ribbon menu item.
1. Scalar displacements
This is an easy assessment; all that is needed is a prism coordinate and displacement value, thus a CSV (comma-delimited) file with columns (c = compulsory and o = optional):
"Easting (c), Northing (c), Elevation (c), Displacement (c), PrismID (o)".
Load a DXF-file of the pit shell for the area of interest with "Ribbon => Mesh => Load and import different file formats => Load DXF".
Load the CSV-file into GEM4D with "Ribbon => Marker => Load files => Text (CSV)", or drag-and-drop the CSV-file into the scene and select "Yes" for Marker-data.
Follow the same logic on the left "Marker" panel as explained in the "Vector displacement => Step 1: Create a pit surface coloured on displacement magnitude" discussion below. The mesh colouring result will look similar as for vector displacements, but the vector arrows will not be displayed.
2. Vector displacement
This assessment requires prism coordinates for two dates, and a vector is calculated between the start and end coordinates. Note that the selection of two dates could results in the loss of prism data, as some prisms could be installed after the start date, or prisms could be lost before the final date. The two calculation methods used in PrisVec try to solved these issues, but that could again cause artifact that should be recognised. Play with both methods and use the one most suited to your circumstance.
Many vector calculation methods are possible, and PrisVec has two options:
"Best-fit line" (default) which fits a linear line through the data points of each prism, and then extrapolate displacements to the selected start and end dates. Thus, even if a prism is only available for a short period within the selected time interval, a line will be fitted to the data points and extrapolated to the start and end dates. No prisms are thus "lost" with this method.
"Start to end" which use the "Days" and "Maximum number" settings in PrisVec. A median start and end coordinate is calculated from these settings, and the vector determined from the coordinates of these median dates. Both a start and end coordinate is required for a prism, otherwise the prism will be discarded.
The process to create the image below this discussion is a two-step process, but the steps could be used independently.
Load a DXF-file of the pit shell for the area of interest with "Ribbon => Mesh => Load and import different file formats => Load DXF".
Export or prepare the prism data in a file with format "DateTime, PrismID, Easting, Northing, Elevation". DateTime is any format supported by Excel, and would typically be "Day/Month/Year Hour:Minute:Second". Both the the UK (Day/Month/Year) and US (Month/Day/Year) formats are supported, and the latest PrisVec will auto-correct the UK/US setting based on the input data.
Open PrisVec with "Ribbon => External => Instrumentation => PrisVec (prisms)" and load the data with "Load prism data as "DateTime, PrismID, X, Y, Z"".
Select the "Displacement selection method", "System of measurement", "DateTime format", "Date extraction period of interest" (and other settings if required), and press "Create GEM4D displacement vectors" and provide a file name for the CSV results-file.
Repeat the process with as many date ranges as required and close PrisVec.
Step 1: Create a pit surface coloured on displacement magnitude
Load a PrisVec results file with "Ribbon => Marker => Load files => Text (CSV)".
Change the data points to spheres with "Left panel => Marker => Marker type => Shape => Sphere".
Change the sphere size with "Left panel => Marker => Marker type => Shape size".
Change the sphere colour by changing the column on which the colouring is based with "Left panel => Marker => Colour Mode => DataColumn => 5". Column 5 from the PrisVec results-file is the calculated velocity in "mm_per_day".
Change the colouring mode with "Left panel => Marker => Colour Mode => Mode => Manual".
The upper and lower limits of the colouring can now be changed with "Left panel => Marker => Colour Mode => Value start/end".
Reverse the colouring scheme with the checkbox "Left panel => Marker => Colour Mode => Reverse colour". Small displacement values will now be in cooler colours (blue) and larger values in warmer colours (red).
Colour the pit shell on the selected values by checking "Left panel => Marker => Iso-surface and Colour mapping => Colour meshes". Click the "Settings"-button to customise the colouring parameters (optional).
If less values are required, the number of colour values could be limited with a number less than the default 99 with "Ribbon => Markers => Scalar bar settings => Colours", and then pressing "Left panel => Marker => Iso-surface and Colour mapping => Update."
Step 2: Create coloured vector arrows
Load a PrisVec results file with "Ribbon => Mapping => Load files => Text (CSV)". The same data-file is thus loaded twice; first as Marker-data to get access to the mesh colouring and interpolation functionality, and then as Mapping-data to get access to the vector functionality.
Change the data points to arrows with "Left panel => Mapping => Orientation shape => Shape => Arrow".
Change the arrow size with "Left panel => Mapping => Orientation shape => Shape scale", and increase until the arrow protrude from the Maker-spheres.
Change the arrow colour by changing the column on which the colouring is based with "Left panel => Mapping => Colour Mode => DataColumn => 5".
Change the colouring mode with "Left panel => Mapping => Colour Mode => Mode => Manual".
Change the upper and lower limits of the colouring with "Left panel => Marker => Colour Mode => Value start/end" to be exactly the same as the Marker start and end dates.
Reverse the colouring scheme with the checkbox "Left panel => Mapping => Colour Mode => Reverse colour".
If required, re-scale the arrows according to their displacement values with "Left panel => Mapping => Orientation shape => Scale on value". Change the arrow size again with "Left panel => Mapping => Orientation shape => Shape scale".
Change the scalar bar text size with "Ribbon => Mapping => Scalar bar settings => Text" if required.
