In MERAKA attribute information is only considered if they do not belong to the raw but to 
the manipulated data. So three different kind of metadata are distinguished: metadata concer 
ning the raw geometry, the manipulated geometry and the map geometry including related attri 
butes. 
Additional to general information like purpose, name of the institute and responsible scientist, 
validity, time and spatial scale range, information about the geometry (point, lines, polygons), 
among others the sources of the data, the resolution, quality and positional accuracy are stored. 
Often information refers to the raw data, which are stored in the FAM database. Besides the 
new calculation of attributes, the geometric manipulation by buffering, intersecting, clipping 
etc. must be documented and connected to the layers (coverages, grids, tins, images), which are 
exported. When visualizing those derived data in a map, the metadata of the used coverages or 
layers are accessible and additional information concerning the ‘mapping constraints', e.g. 
generalisation, readability and purpose are stored (Figure 3). 
Question 
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Figure 3: Metadata structure of geometric data and maps 
The system is written in AML and based on the FGDC standard and on the document tool, 
which creates the four INFO tables. All aspects of the FGDC standard are stored in INFO 
tables, although in MERAKA there exist two main differences: MERAKA extends the FGDC 
standard concerning the further evaluation and processing of the geometric data (interpolation, 
classification etc.) (Figure 4). The cover information can be retrieved and saved in a textfile