Defining a Survey (ASCII Volume)

In the Survey window, choose whether to use analysis results to create or update a survey, or to use an existing survey.

Note: In Insight, a 2D survey is a collection of related 2D lines. Every line is defined by a set of tie points that associate common midpoints (CMP) to eastings and northings (X/Y). If two ASCII files have the same CMP to X/Y tie points, then they sit on the same survey line.

2D Survey Options

Define a survey file
  1. Choose how to handle the survey 2D line geometry:
    • Import a survey: Import an existing survey file directly. Only a survey file in Insight’s format (.survey) is supported.
    • Create new survey called: Create a new survey in the project for this line geometry. Enter a name for the new survey.
    • Use existing survey: Use the line geometry from an existing 2D survey in the project. Use this option when loading related data on the same lines. Tie points are displayed but are not editable.
    • Add to/edit existing survey: Add the line geometry to an existing 2D survey. New lines are added to the survey. Existing line geometry is replaced with the new tie points.
    • Note: Specify new line names to avoid replacing existing geometry. The geometry will be written to the new line names.
  2. Simplify all lines with a maximum error of (m):
    • Set a tolerance level (m) to simplify lines.
    • Insight only requires tie points when the line changes direction or spacing, and unnecessary tie points can make some operations slower. This setting removes points within this distance from the simplified line.

When creating a new survey or adding to/edit an existing survey, the following options are available:

  1. Add and/or remove tie point rows
    • Click the Plus button to add an empty tie point row.
    • Click the Minus button to remove a tie point row.
  2. For SEG-Y and/or navigation file that contain(s) both CMP and shotpoint (SP), define the SP-to-CMP mapping using the CMPs/SPs relationship calculator (see below). Enter 2 CMPs and shotpoint values and click OK.
  3. Click Assign Missing CMPs/SPs and any missing CMP/SP numbers will be generated using this relationship.
  4. If you have selected the option to calculate the tie points from the X/Y headers, you will see the tie points that have been automatically calculated by the SEG-Y Loader.
  5. Change the values of the tie points by typing the values in the CMP, SP, X and Y columns.
  6. Click Reset tie points to reset the values to the automatically calculated tie points or to remove the manually entered tie values .
  7. Click Next.

3D Survey Options

Define a survey file
  1. Choose how to handle the survey:
    • Import a survey: Import an existing survey file directly. Only a survey file in Insight’s format (.survey) is supported.
    • Create new survey called: Creates a new survey for the project database. Enter a name for the new survey.
    • Use existing survey: Use an existing survey for the data loading.  Click the arrow icon to choose from a list of existing surveys.
Define a survey file
  1. Enter three tie points in the IL/CL to X/Y Tie Points table. This information is sometimes provided in the EBCDIC Header.
  2. If using the option Calculate tie points from X/Y headers, the table will contain the tie-points found during the analysis.
  3. Click Reset tie points from analysis to replace the current values with the tie points found during the analysis.
  4. The IL spacing, CL spacing, IL orientation (survey azimuth) and Angle between ILs and CLs are calculated from the tie points. A warning is displayed if the angle between ILs and CLs is not perpendicular.
  5. Click Next.
  6. For examples, see Survey File Examples.

Note: A survey defines the relationship between Inline/Crossline and Eastings/Northings (based on the tie-points). In Insight, surveys extend in all directions and do not include the IL and CL ranges. If Insight finds another survey in the project with the same IL/CL to X/Y relationship, it will NOT allow you to create a duplicate survey,  i.e. If two sets of tie points convert IL/CL values to the same X/Y coordinates, they are considered duplicate surveys (see Why does SEG-Y Loader tell me I have a duplicate survey even though the coordinates are not the same?).

Genuine offer of assistance

DUG understands that importing ASCII volume data can be a confusing task.

Whether you are using a trial version or a fully-paid licence, we will help you to import your data to Insight so that you will get the maximum out of your data.

For more information, contact support at support@dugeo.com.