Import from Geosoft Voxel

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Import from Geosoft Voxel

Summary

Use the Import from Geosoft Voxel tool to import a Geosoft voxel as a netCDF voxel that can then be added to any scene in ArcGIS Pro and visualized.

Usage

What is a Geosoft Voxel?

Voxels (3D raster block models) are a common data type used in subsurface exploration, where each 'cell' (3D cube) contains one or more values, usually the result of estimation (interpolation) from a more sparse measured dataset (e.g. drillhole assay values).

Geosoft voxels are 3D files created by Geosoft desktop applications (i.e., Oasis montaj, Target, Target for ArcGIS) from 3D data contained in a Geosoft database (GDB file). The data to be gridded must have defined X, Y and Z fields that locate the data within a coordinate system in which Z coordinates are interpreted as positive up.

Geosoft Voxels store the following information:

XYZ location
Coordinate system
Attributes including transparency, color and fill

Parameters

Parameter	Explanation	Data Type
Geosoft voxel	Select the Geosoft voxel file to import. The voxel can contain either numeric values, or in some cases, string or text values as data – these are also called "Long [Thematic]" or "Lithology" voxels. See the Technical Notes below for details on Lithology voxels. Rotated voxels and voxels with variable cell sizes are not supported.	Geosoft Voxel File (*.geosoft_voxel)
Output NetCDF file	Specify the name of the output netCDF voxel file. This field is auto-populated based on the root name of the input voxel with the (NC) file extension added to it. The netCDF file format is the storage on disk; when this is loaded into a Scene in ArcGIS Pro, it is referred to as a "voxel layer". It is similar to how a set of points would be stored in a Feature Class, but when displayed on a map or scene, it is called a "feature layer". See the Technical Notes below for details on the netCDF voxel format.	NetCDF (NC) File (*.nc)
Variable name	Provide a descriptive name for the data (variable) that will store the imported information into the netCDF file. The data is then visualized as a voxel layer, which is added to the Contents pane once the import completes. If not specified, the variable name defaults to "v". Geosoft voxel files do not store any embedded information about what the variable value is or what it represents. In netCDF voxel files, this variable can be magnetics, gravity, resistivity, conductivity, or any of the geochem assay values. This is like the 'Column' name in a Geosoft database (GDB) or the 'Attribute' name in an ArcGIS Pro attribute table. See the Technical Notes below for details on the netCDF voxel format and variables.
Description	If specified, the variable description will be written into the netCDF file; this can be a longer name, e.g., "total field magnetics".
Add voxel to a new scene	Specify if the 3D voxel layer will be displayed into the current map, or it will be added to a new scene window: Checked - The output voxel will be displayed in a new scene. Unchecked - The output voxel will be displayed in the current scene. If the Section View is enabled in the current scene and the view is in "Perspective" mode, the voxel will be displayed inside the section view, and it will be sliced/clipped to the extents of the current section. Read more about ArcGIS Pro Voxel layer exploration tools. The voxel layer is positioned in the scene (XYZ location and origin point) in real-world coordinates, and it is displayed with the input voxel colors applied (the imported legend/symbology is displayed in the Contents pane). In addition, the number of cells in each direction (XYZ) and the cell size of the input voxel are retained on import. See the Technical Notes below for details on the coordinate reference system of Geosoft voxels.

Technical Notes

ArcGIS Pro Related Documentation:

What is a voxel layer?

https://pro.arcgis.com/en/pro-app/help/mapping/layer-properties/what-is-a-voxel-layer-.htm

"A voxel layer represents multidimensional spatial and temporal information in a 3D volumetric visualization. For example, you can visualize atmospheric or oceanic data, a geological underground model, or space-time cubes as voxel layers."

Supported voxel formats

https://pro.arcgis.com/en/pro-app/help/mapping/layer-properties/supported-voxel-formats.htm

"A voxel layer represents volumetric, regularly gridded data. The netCDF format is a self-describing file format for storing array-oriented multidimensional data, specifically designed for scientific variables, such as temperature, humidity, pressure, and soil type. The netCDF format is a widely used open data format. To assure that the data can be read as a voxel layer, it must follow the Climate and Forecast (CF) convention. Currently, only CF-compliant netCDF data with no auxiliary variables as a data source is accepted as a source for a voxel layer."

What is NetCDF data?

https://pro.arcgis.com/en/pro-app/help/data/multidimensional/what-is-netcdf-data.htm

"NetCDF (network Common Data Form) is a file format for storing multidimensional scientific data (variables) such as temperature, humidity, pressure, wind speed, and direction. Each of these variables can be displayed through a dimension (such as time) in ArcGIS by making a layer or table view from the netCDF file."

Geosoft Lithology Voxels

Lithology (string voxels) store discrete categorical data instead of continuous numeric data (numeric voxels). When data from a lithology type voxel is imported into a netCDF file, the string/text values (discrete categories) and the colors associated with the lithology (rock types) are imported. The output voxel will be displayed based on the symbology imported: the legend in the voxel layer (Contents pane) will show the 'rock names' (string values) associated to their respective colors (codes).

Geosoft Voxels - Coordinate Reference System

Geosoft Voxels (and most other voxel datasets) have local coordinates internally to the voxel structure. The entire cube, which is made up of many smaller cubes, starts at one corner (0,0,0) and has a cell size and a number of cells in each of the three directions (some voxels use XYZ, some use UVW). This defines the full extent of the voxel dataset.

In addition, voxels have information that locates them "in the real world" - this includes the CRS (Coordinate Reference System), and an Origin (or "Tie" point). This origin is usually the true XYZ location of the 0,0,0 point, which anchors or 'ties' the voxel to a specific point on the earth. This information is needed to correctly locate a voxel in any 3D visualization software.