6.0 IMAGE TO ADRG

In Image to ADRG (Arc Digitized Raster Graphics) mode, a search image is displayed and reference points are selected from scanned maps. ADRG maps are actually 24-bit images in a special format which are distributed on Compact Disks.

To display an ADRG image, the user must select the ADRG general information file (.gen) located in the root directory of the CD. The general information file displays geographical and other metadata on the ADRG image(s). Upon selecting the .gen file, an ADRG overview image is translated into a LAS image and displayed. The overview image contains every 16th line and sample of the full resolution ADRG image. From this point, ADRG mode is identical to IM2IM..

ADRG may seem a little slow, since every request for a full resolution image requires a 512x512 region be read from CD, converted into a LAS image ("extract.img"), and loaded into TIEPTS.