The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
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s
USER
UPLOAD
input
query
information
DOWNLOAD
(link)
data storage
(AFS)
BACKUP
->
upload
meta data
Web-Interface
WebGIS
input
—>
content & structure
non-spatial DB
(MySQL)
S
ADMIN
Figure 2. TR32DB Design
purchased data include geodata like topographic, elevation,
remote sensing, soil, land use or weather data in different scales.
Besides collected measured data and purchased data, further
data e.g. publications, reports, videos, and pictures of the TR32
participants need to be managed with their corresponding
metadata.
The TR32DB-Structure (see Figure 2) is basically subdivided in
three components: (i) data storage, (ii) databases, and (iii) web-
interface. The data storage is the system component where the
project data is physically stored (upload of data). The database
stores associated metadata and administrative data. Finally the
web-interface provides uploaded project data of (download of
data) and information about the TR32. A backup of the whole
system is continuously done. In the following paragraphs, each
core component of the TR32DB system is described in detail.
3.1 TR32DB Data Storage (upload of data)
The essential data storage of the TR32DB (upload of data) is
carried out in the already established AFS. The latter was
chosen in cooperation with the ZAIK/RRZK due to the
mentioned reasons under 2.1 and additionally due to the support
opportunities provided by the ZAIK/RRZK. Furthermore, the
cooperation with a local computing center is requested by the
DFG.
In detail, the TR32DB file database is organized in a folder
system. Due to the fact that the TR32DB contains a multiplicity
of several project data, the data is arranged in different folders.
This is designed in a specific hierarchy according to the
mentioned structure of the TR32. The folder structure is
therefore ordered by: (i) cluster, (ii) project sections and (iii)
data type. The data type is divided into: data, publications,
pictures, presentations and reports. Only users who are
participants of the TR32 are authorized to store their data in the
TR32DB.
The upload of data within the AFS operates as follows. Users
who are authorized to the AFS system own a specific view in
their home directory. They have the opportunity to store their
data directly via copy and paste in their particular project
section folder sorted by the five data types. The actual project
section folder is joined by a symbolic data linkage with a
directory in the TR32DB. Consequently, uploaded user data is
immediately located in the TR32DB system. The data is moved
into the final folder directory by a script that is developed in
cooperation with the ZAIK/RRZK. The developed solution has
several advantages. These are basically the immutability and
documentation of the moved data files. A database entry is
automatically generated by the script for each moved file that
contains e.g. the file name, the file extension, and the final file
storage directory. Only the administrators are permitted to edit
or delete documented information in the database as well as the
data file directory in the AFS.
The announced system has some restrictions. Some are set by
the actual AFS version like a single file size limit of 2GB
(which will be increased in near future) and others are
established by the administrators for safety aspects. These are
limitations like access restriction for other project section
folders due to the user AFS-account. This has the advantage
that the administrators are able to define the exact folders where
users are permitted to store their data. Users are required to
label their data files in a well-defined manner and compress
them if possible. Furthermore, the current folder size of the data
types is limited to 8GB (which will be extended in near future,
too). Therefore, each SP is only able to upload 8GB per data
type in their specific folders per day since the script operates
over night. In exceptional cases a movement of data managed
by the administrators is possible.