How to Import a Survey from SPS Format

1. OW-0601EN How to Import a Survey from SPS Format OMNI 3D Version 9.0 Created April 27, 2009

2. Enter the extension of the files you want to load. The extensions in the picture are typical for SPS files. • To make sure the files are being read in correctly, select View and/or Edit Column Definitions. • Press Browse All SPS Files... to read shots, receivers and script (i.e. X) • The file names are automatically entered in the text boxes when I press Open. 2

3. The column definition tells OMNI 3D which columns belong with which header. A column is a single character space. The yellow 5 under Point Name is character number 25. 3

4. Here’s what you’re looking at: Select any value in the table by left-clicking on it or use the drop-down menu beside the Header name text box. Highlighted column range Header name of selected data value File data for selected row: Highlighted columns show what OMNI 3D is reading for the selected data value. Selected data value 4

5. Notice that Line Name row 59 is only reading 93. OMNI 3D can’t see past the hyphen. It also can’t see past letters (i.e. alphas). Using your cursor, click and drag over the columns that OMNI 3D needs to read. This corrects the definition for that header. Corrected Definition 5

6. Check each header one by one to make sure it’s reading the data correctly. ETC. 6

7. It’s also important to check • the number of digits in the data values. • If your coordinates don’t show the correct number of digits, they may have been multiplied by a scalar. This is commonly done when equipment can’t handle decimals. • You can define this by using the multiply by parameter in the top right corner. • For example, if your coordinates have one too many digits, multiply by 0.1 to regain the decimal. • If a header has all zero values, check to see if they are being multiplied by 0. 7

8. Now we’ll look at the options at the bottom of the Shot and Receiver File Column Definition windows. Field Line Numbers: This lets us specify a range of data rows to load. OMNI 3D defaults to the total number of rows in the SPS file. In the table, select a data value in the first row of our specified range. That row number is then displayed after Selected. In the above diagram, a value in row 58 has been selected and I have pressed Load From. Alternatively, if we had known the row number before selecting from the table, we could have entered the value in the Load From parameter text box. Repeat for the Load To button to end the range, but select or enter the last row of the range. 8

9. Interpolate Missing Stations: • When Interpolate is checked, OMNI 3D will interpolate station numbers for missing stations. It assumes stations are spaced at a uniform interval between the last station before the gap and the first station after. • Excluded stations are simply place holders. However, in scripts they are very important for the receiver set up. Without the placeholders, the patch becomes distorted. See the bottom two diagrams for a simple illustration. • The black border shows the template. • (Template = patch + associated shots) • Increment specifies how to number the interpolated stations. Template; no stns missing Template; with stns missing 9

10. Fixed Elevation Value: When Fixed is checked, OMNI 3D will assign a constant elevation to all stations. 10

11. Create Attributes for: • If your SPS file has values for an attribute, you can ask OMNI 3D to read and save them. Simply check an attribute listed in the scroll menu. • Ensure that the columns for that attribute are properly defined for your values. 11

12. Point Codes: • OMNI 3D has special utility for reading alphas. It can read alphas if they are in the Point Codes data values (in the table). • Stations that have a certain quality can be marked with a letter. If that letter is entered in the Point Code text box, OMNI 3D will be able to identify it and perform the requested operation. • Marked stations can be excluded or be the only stations loaded (Add Only if). • Example qualities: • station out of range (i.e. Depth) • a particular 3D geophone component • trace to be killed 12

13. ADD new Stns: Check this when you are adding new stations to your survey. REPLACE pre-existing Stns: Check this when you are adding stations that have the same line and stations numbers as stations already in your survey. OMNI 3D will replace the pre-existing station. REMOVE all pre-existing Stns: This will delete all stations you already have in your survey, and create the new stations at the same time. 13

14. Set Default Definition: Press this when you want to use the default definition. Save This Definition: If you will be reusing the current definition, press this to save it to file. Read Existing Definition: Press this to read a previously saved definition. 14

15. The X-File wizard works the same was as what I’ve explained. The only difference is that there are fewer options at the bottom. • The following values must match the Shot and Receiver File values: • Shot Line numbering • Receiver Line numbering • Shot Point numbering • Receiver Station numbering 15

16. In the SEG SPS Definition there are two fields that are not in OMNI 3D’s SPS Relational File Read dialog. These are “from channel” and “to channel”. Channel To & From are not included in the headers because OMNI 3D doesn’t use that information. Not including them saves screen and memory space. 16