Grid Multiple Channels

Use the Grid and Image > Gridding > Grid Multiple Channels menu option (geogxnet.dll(Geosoft.GX.GridUtils.ChannelsToGrid;Run)*) to grid multiple channels using the same gridding method.

Grid Multiple Channels dialog options

Database channels	Select (highlight) the database channels you want to grid.
Channels to grid	Your selected channels to grid are displayed here.
[Add]	Click the Add -> button to add the selected (highlighted) database channels to the Channels to grid window.
[Remove]	Click the <- Remove button to remove the selected (highlighted) channels back to the Database channels window.
Gridding method	Use the drop-down list to select a gridding method: Minimum Curvature Bi-Directional Line Gridding Kriging Inverse Distance Weighted Gridding Multi-Trend Gridding
Mask channel	Select a channel from the drop-down list to act as a mask (or filter) channel. This field is optional. String channels and channels with array size > 1 are omitted from the list. The data values in the Channels to grid with corresponding dummy () values in the Mask channel* will not be used in the gridding process.
Grid cell size	Specify the grid cell size in data units. The calculate button positioned next to the field determines a default cell size. If the cell size is left blank, the default cell size is used. See the Application Notes below for more information on calculating the default cell size.
Grid name prefix	Specify a grid name prefix to be added to every grid.
Grid name suffix	Specify a grid name suffix to be added to every grid.
Output grid type	Select an output grid format from the list. (Geosoft colour grid formats are excluded from the list.) The default output grid format (set in the General Settings dialog) is automatically selected as the Output grid type. The grids will be created with the format selected and the associated extension. Some grid types do not have an explicit extension type (.) – they will be created with the (.grd) extension, and all the associated files will have the expected extension (e.g., .grd.gi, *.grd.xml).
Destination folder	Use the browse button located next to the field to select the destination folder. The default is your current project directory.
Display option	Use the drop-down list to specify how to display the generated grids: On the current map as aggregate layers In individual grid windows Do not display The first option will be available only when there is a current map opened.
[Advanced]	Click this button to view and set the advanced gridding parameters based on the selected gridding method: Minimum Curvature Bi-Directional Line Gridding Kriging Inverse Distance Weighted Gridding Multi-Trend Gridding
[Run in background]	Gridding is a computationally intensive operation that may take minutes to hours, depending upon the size of the dataset(s). Check the Run in background box to run the gridding process asynchronously, so that you can perform any other operations in Oasis montaj while the gridding is occurring. Multiple grid creation processes can run concurrently in the background for the same database or different databases. When you press the OK button with the Run in background option checked: An Oasis montaj command-line window (OMS) opens: gridding progress and grid creation steps will be reported here. The instance remains open during and following completion of the gridding, and Oasis montaj becomes available immediately after the script window is launched. Do not close the OMS script window prior to finishing the gridding process — this will cancel the gridding process and will not produce the output grid file(s). In the current Oasis montaj project, in the Project Explorer: The gridding progress and status (i.e., processing, completed, failed, canceled) are recorded in the Jobs tab. The output grid(s) will be added to the Grids node in the Data tab as the gridding process for each grid completes. Closing Oasis montaj while the background gridding is in progress: The process will execute to completion and the grid(s) will be generated. Upon re-opening the project, the grids generated after the current project was closed will not be loaded to the Project Explorer Grids list. The selection state of the Run in background option is retained on subsequent runs of the gridding tool in the same project. When gridding using minimum curvature, krigging, or bi-directional line gridding, unique, time-stamped log and control files will be added to the project folder. (This is to avoid conflicts, which would otherwise arise when running background gridding on the same database when the same channels are involved.)

Application Notes

See below for grid cell size information for each of the gridding methods:

Cell Size - Minimum Curvature Gridding

The grid cell size is in the distance units of the data. We recommend a cell size of ¼ to ½ the nominal data sample interval. The default is one quarter the average data separation based on a statistical average. A smaller cell size may be required if the data is to be contoured (we recommend 2 mm. or 1/10 inch at plot scale for contouring). This can be achieved by specifying a smaller cell size and larger desampling factor (desamp), or by regridding the grid using BIGRID.

Cell Size - Bi-Directional Gridding

Specify the grid cell size. The cell size is the distance between grid points in the X and Y directions. In most situations, the cell size can be selected as 1/4 to 1/8 of the line separation or the minimum station interval, whichever is greater. By default, BIGRID will choose a cell size based upon these criteria, although we do recommend that you choose the cell size directly.

Cell Size - Kriging

Specify the grid cell size. This should normally be ¼ to ½ the nominal data sample interval. If not specified, the data points are assumed to be evenly distributed and the default cell size will be set to one quarter the average data separation based on a statistical average.

Cell Size - Inverse Distance Weighted Gridding

Specify the grid cell size. The calculate button determines a default cell size using the following formula: Size = sqrt ( Range in X * Range in Y / Number of values ) / 4. If the cell size is left blank, the default cell size is used.

Cell Size - Multi-Trend Gridding

The grid cell size (the distance between grid points in the X and Y directions) should normally be ¼ to ½ of the line separation or the nominal data sample interval. If not specified, the data points are assumed to be evenly distributed and the default cell size will be set to:

Where: