A column files is one in which each data value also has a latitude and longitude associated with it on one line (depth and time being optional). For instance, a line may look like this:
86 270 3.0
Column 1 (86) stores the latitude for that data point, column 2 (270) stores the longitude, and column 3 (3.0) stores the data value itself. The whole file is simply line after line in this format. The columns can be arranged in any way, data first would be acceptable for instance. Also, the program will automatically ignore any extraneous columns.
1 90 0 -460 3 1.02 2 86 0 -460 3 3.12 3 84 0 -460 2 0.34 4 80 0 -460 3 6.89 5 76 0 -460 1 0.07
Column 1 is simply the line number, column two is the latitude, column 3 is the longitude, column 4 is the depth, column 5 is the accuracy of the data and column 6 is the data itself.
The first two requirements are common to all file types, a file to be converted and a file to be created. Use the browse button next to these fields to select the desired files.
The only fields unique to the column file are the following 5 fields. They ask for the column number for each variable, 0 if that variable doesn’t exist (the default for depth and time). In the example snippet above, a 2 would be entered for latitude, 3 for longitude, 4 for depth and 6 for data. The fact that columns 1 and 5 are unnecessary doesn’t effect the rest of the data, and there is no need to eliminate them.
The final fields are common to all file types. The “Is positive depth above or below ground” question (with answer choices above and below) simply means that if the file starts 460km below the surface of the Earth, and you entered in “460” as you’re starting point, then positive would be below the surface. This option can also be changed (with extra work) through the attributes panel, but it is common enough to be a general option on the main panel. The attributes panel is explained fully in the user’s guide.
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