The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
1255 
Figure 3. Image Chips 
3.3 Tracks 
Tracks contain spatial data representing line phenomena (see fig. 
4). 
X 
, /\ 
V, 
X 
w 
/\ 
\ 
\ / 
X 
X s 
Y 
/ 
/ 
\/ 
A. 
/ 
V 
V / \ 
\ / 
v A 
\/ 
X 
/ 
/ 
/ 
/ 
' \ 
\ . 
y 
\ 
V 
X 
A 
/ \ 
X 
\ 
V 
; 
/ 
/ \ 
\/ ' 
X 
\ . 
\ 
V 
/ 
\ 
/ \ 
Figure 4. Tracks 
4. DATA FORMAT SPECIFICATION 
For the representation of Image Chips and Data Tiles the Sun 
Raster File with DLR extension (SRF) (DLR, 2002) is foreseen. 
The files are stored in the database in big-endian byteorder 
format strictly to avoid confusion. For the purpose of enabling 
fast processing the files are kept in machine-specific byteorder 
after the export and prior to the import to the database. The 
DLR footer specifies statistics and the annotation, allowing a 
fast display of statistical information and quick addressing for 
Data Tiles and Image Chips. 
The vector and point data is represented in ESRI's (ESRI, 1998) 
shapefile format. 
5. ORGANISATION OF THE FILE SYSTEM 
The database structure is based on a UNIX file system. The 
different sources of data stored are accounted for by separate 
branches (called projects in the following) in the directory tree. 
Below the project level the grid spanned by the geographic 
coordinate system (fig. 5) is projected onto the directory tree of 
the file system in the order North (two digits ranging from GO- 
89) to South (two digits ranging from 01-90) and East (three 
digits ranging from 000-179) to West (three digits ranging from 
001-180) in 1° steps. 
Figure 5. Geographic coordinate system 
For resolutions finer than 1 arc-second the directory tree is 
further subdivided in 0.01 arc-second steps in latitudes and 
longitudes as well (in both directions represented by two digits 
ranging from 00-99). At each level a logfile is kept to keep 
track of changes made to each subdirectory (fig. 6). 
L 
$W42HOME 
w42_PROJ_NAM 
w42_PROJ_NAM.Iock 
ft- w42_PROJ_NAM.log 
N00 
-U... 
“ÜJ N89 
- S01 
-ta... 
-frail S90 
— E000 
• • • 
E179 
Ü, W001 
W180 
W180S90_PROJ.log 
- „ 00 
99 
- 00 
t 99 
L W180S90_99_99_PROJ.log 
w42_PROJ_NAM_coverage 
contents_YYYY-MM-DD.log 
Figure 6. Directory Structure of the file system