There are a few different ways to create a database from a grid, the most flexible one is the dataset resampler (INTREPID Main Menu -> Dataset -> last entry [dataset resampler]).
The steps are:
- Start the dataset resampler
- Load the reference grid
- Tick on trace profile path and digitise the first line of your survey design i.e. bottom left at right-angles to strike (i.e., East-West if general strike is north-south). Does not need to be accurate, it is just a starting point.
- Open the: Survey Plan-> Design Survey plan and design the survey line spacing and sample spacing for Murthy and Rao. Edit the coordinates of your first line to do whatever you want. The tool works on number of lines and line spacings. You can also choose your sample spacing along line. You need at least two or three tielines in order to give it the width of your survey.
- Save the survey plan as a text file (mysvyplan.txt) using Survey Plan-> Save Survey Plan
- Leave the tool and start as at the first step, but don't digitise just load the survey plan
- Go to File menu and choose Save Profile paths as line dataset/database
- Now Load profile paths as line dataset
- Now Save Reference to loaded dataset - this samples your grid (gravity) into the Line database. This is what you need for Murthy and Rao. You need at least a line number and it is also handy to have a FID. You can generate this in Dbedit ie. Create new field and initialise with Row()
- Gravity must be in Milligals for Murthy and Rao.
- You should also sample your DTM into the Murthy and Rao database. You will need this later to convert the Murthy and Rao depths below surface to elevations for Geomodeller.