Take a look at the Terrain commands...
Save Terrain for some reason is not in the help documents nor is it showing the syntax, but it does highlight...
The Syntax is:
SAVE TERRAIN "FileName.dbo", TERRAIN NUMBER
Must be .DBO and then the Terrain Number is an integer value
And then
LOAD TERRAIN "FileName.dbo", TERRAIN NUMBER
Simple...
Matrices I believe there is a bit of fiddling to get them saved, But it might be do-able...
The rest of the Terrain commands can be found partially in the DBPro help documents, or using Hands On DarkBASIC Professional Book 2, there are approximately 20 Terrain commands... half of them never documented it would seam...