Data Requirements Overview
The collection and formatting of data for volumetric modeling is often the most challenging task for novice EVS users. This tutorial covers the instructions for preparing and reviewing all types of data commonly used in Earth Science modeling projects.
The next topics will demonstrate how to visualize these file formats, helping to ensure the quality and consistency of your data.
The following guidelines will simplify your data preparation:
Use a single consistent coordinate projection (e.g. UTM, State Plane, etc.) for all data files used on a project, ensuring that X, Y and Z coordinate units are the same (e.g. meters or feet).
For each file, you must know whether your Z coordinates represent Elevation or Depth below ground surface (most EVS data formats will accommodate both)
Understand the data formats and what they represent. Below is a list of C Tech's primary ASCII input file formats:
Analytical Data files can be used for many types of data and industries including:
APDV: The Analytical Point Data Values (.apdv) format should be used for all analytical data which is (effectively) measured at a point. Even data which is measured over small consistent (less than 1-2% of vertical model extent) intervals should normally be represented as being measured at a single point (X-Y-Z coordinate) at the midpoint of the interval. Time domain data for a single analyte should use this format.
AIDV: The Analytical Interval Data Values (.aidv) format should be used for all analytical data which is measured over a range of elevations (depths). Data which is measured over variable intervals, usually exceeding 2% of vertical model extent should use this format. Time domain data for a single analyte should use this format.
Chemical or assay measurements
Geophysical data (density, porosity, conductivity, gravity, temperature, seismic, resistance, etc.)
Oceanographic & Atmospheric data (conductivity, temperature, salinity, plankton density, etc.)
Time domain data representing any of the above analytes
PGF: A PGF file can be considered a group of file sections where each section represents the lithology for individual borings (wells). Typical borings logs can be easily converted to PGF format, and many boring log software programs export C Tech's PGF format directly.
GEO: This file format represents a series of stratigraphic horizons which define geologic layers. GEO files are limited to data collected from vertical borings and require interpretation to handle pinched layers and dipping strata. The make_geo_hierarchy module may be used to create GEO files from PGF files, though they can be created in other ways.
GMF: This file format represents a series of stratigraphic horizons which define geologic layers. GMF files are not limited to vertical borings as GEO files are. Each horizon can have any number of X-Y-Z coordinates, however interpretation is still required to handle pinched layers and dipping strata. The make_geo_hierarchy module may be used to create GMF files from PGF files.
Geologic Data
Analytical Data
The C Tech Data Exporter will export the above formats for data in Excel files and Microsoft Access databases. In all cases, the data source must contain sufficient information to create the desired output.
It is important to view your data prior to using it to build a model. There are many common file errors that can be quickly detected by viewing your raw data files, including:
Transposing X & Y (Easting and Northing) coordinates
Using Depth or Elevations incorrectly
Consistency of geologic and analytical data
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