Please consult this page in the user-guide for the latest list. Note additional formats may be available with the help of plugins.
Depending on the map-viewing application you use, L3DT maps map appear to be inverted in the y-axis. This is because L3DT uses a right-handed coordinate system, following the convention in mathematics and the physical sciences, which puts pixel (0, 0) at the bottom left-hand corner of the screen (i.e. the southwest). Most 2D graphics applications use a left-handed system with y-inverted so that pixel (0, 0) is at the top-left of the screen (i.e. northwest).
To make L3DT more compatible with this other coordinate system, L3DT includes an 'invert y-axis' option for most file formats. To edit this option, use the 'options…' button in the export wizard or the file preferences dialog.
From the menu, select the 'File→Export→Export map layer' option, then the 'Heightfield' option. This will open the export map wizard, which is described here. The supported file formats are listed on the file formats page.
Yes, L3DT supports the export of heightfields as 16-bit PNG, PGM, and RAW image files.
Yes, disk-paging has been an integral feature of L3DT since release 2.1 (Nov 2003). In L3DT, paged maps are called mosaics because they are split into tiles that are loaded into RAM as required and saved back to the disk-drive when not needed. To make a mosaic map, see the following tutorial pages:
The technical details of the disk paging implementation are discussed on the mosaic algorithms page.