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Clicking on the right button over the tree permits access to some additional functions. The functions available will also depend on the type of element selected on the tree. The functions provided mostly permit management of the relations between tables and databases (create and delete links) and the structure of multiband images (add and remove bands from multiband images).
1.1 Principal REL file
VECTORS: the name of the principal REL file cannot be changed. This is because for vectors (and for REL1 rasters) the principal file name is deduced directly from the layer name and, therefore, is a fixed number. In the case of structured vectors, in the right hand part of the tag an example is shown of a position query for a graphical element (with a defined value of the Graphical Identifier, in case of multiple registers only the first is shown). This is useful for designing positional queries.
RASTERS: In the
case of REL1 metadata format, the REL file is a DOC file with a fixed name
(the same name as that of the IMG that accompanies it) and it cannot be
modified. In the case of REL4 raster files the name of the file is free (and
can be modified), although it is recommended to continue to use the same
system and to select a suitable name corresponding to the number of bands it
contains. In the case of multiband files the REL name should be
representative of all the bands.
1.2 Distributed REL file (only for REL4 format metadata)
In the case of distributed REL file the name can be anything (although it is recommended to use the same as that of the table that accompanies it but with the REL extension) and for this reason it can always be changed.
2.1 Principal Table
In the right hand part of the tag the option is given to "Show the table contents" and to "Open with MiraDades". These options are under a button and are not immediate because for big tables they could slow down the display box so it is preferable to perform these functions only when the user specifically requests them.
2.2 Field in the principal table
The creation of new links is permitted to DBF tables, via ODBC or REL files (which define a table and its properties). In the case of metadata and relations in REL1 format it is only possible to define a link for a field and this must be with a DBF format table.
The names of the files containing metadata (.dvc) cannot be changed, neither can links be generated.
4.1 Multiband images
For REL4 metadata format the structure of a multiband image can be managed, adding or deleting bands from the multiband image. For REL1 metadata this level does not appear in the relational tree.
4.2 Band
For REL4 metadata format new links are allowed to DBF tables, via ODBC, REL file (that define a table and its properties) and with a new DBF table that is created with all the existing values in the raster, ordered and without repetitions. This last option is useful typically for generating a thesaurus of categories. There is also an option to create a single image from a multiband image band.
For REL1 metadata format the rasters cannot have associated tables. It is only possible to define the categories that describe the raster values. For this reason the contextual menu can be used to create, edit and delete the categories. In the case of a continuous quantitative raster the conext menu allows the definition or import of categories from another DOC file or from a categories table in DBF format. In the case of categorical rasters this is shown with a menu level in the relational tree and the options of the context menu allow categories to be changed or deleted. (If deleted the raster is converted into a continuous quantitative raster).
Table
For REL4 format metadata, and if the table is not defined in the distributed REL file, the options offered are "Delete the link" and "Create distributed REL file" (that will store all the metadata that describe this table, its fields and relations). To delete a link to a table that is described in the distributed REL file it is necessary to look for the options given for the REL file. In both cases the right hand part of the tag gives the option to "Show the table contents" and to "Open with MiraDades".
In the case of REL1 format metadata the only option available is to delete the link.
Fields of the associated table
For REL4 format metadata new links can be made to DBF tables via ODBC or REL files (that define the table and its properties). For REL1 format metadata it is not possible to define any links from the fields of the associated tables (only relational levels are allowed).
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