Dataset Propreties - Dataset Structure Contents

The Contents tab contains information about the structure of the Dataset. Two subtabs are available : Model and Table Join.

The Model tab shows 2 panels : a tree-view of the structure of the dataset at the left, and modifiers at the right.

In Orbit, all Datasets contain Models. Models contain spatial data that complies with the model definition. This model definition is listed in the Content-Model tab.

For each model, the definition is listed in a tree-view:

1. Description (either stored in the resource or generated by the resource driver)
2. model identifier
3. amount of spatial objects
4. Spatial Component details
   ( type, bounds )
5. Attribute Component details
   ( attribute tables, field definitions )

For more information about the way Orbit handles spatial data, read the appendix Understanding Orbit Datastructures.

Just below the model tree view, there are buttons to help you navigate in the tree. Select a model in the tree to activate the buttons.

Open all	Opens the tree for all models to the lowest level
Close all	Closes the tree to list only the models
Open one	Opens the tree for the selected model only - double click to open the Attributes tree node
Close one	Closes the tree for the selected model only

In Orbit GIS, the right hand side provides modifiers to alter the structure of the Dataset. There are three changeable elements : Naming, Structure and Rules. The top listbox allows choice between these three.

Many resources are created with cryptic naming, causing problems to understand the meaning of it's values. Orbit can register User Naming to make your data look better. The User Names do not alter the Dataset, but are registered as extension to it in the Orbit Resource Descriptor file.

You can enter User Names for :

• The Model name & description
• Each Attribute Set
• Each Attribute

You can also set the name for the Dataset in the General tab.

Select the item in the tree view and enter your name for the item, then click 'Set'.

Within each model, you can choose one attribute as 'Primary Attribute'. Orbit will use this attribute value to identify an object. It is advised to select an attribute that has valuable content to allow identification of the object. See also the Object Inspector window.

Any attribute of datatype STRING can be specified as being a hyperlink. When a valid URL is entered as value for this attribute, Orbit GIS will be able to execute the URL dynamically (see hyperlinks in the Object Inspector ; the hyperlink function in the object inspector attribute toolbar will launch the hyperlink).

You can also choose to execute the hyperlink upon selection of an object. Just switch on the 'Activate URL at Selection' flag. But beware : do so only for a single attribute within the dataset : Orbit GIS will automatically execute all hyperlinks for all selected objects which may cause overkill when using this type of functionality.

A single active hyperlink can be exported to the hyperlink function of Orbit FlashMap(r).

Hyperlinks can be defined with metatags. These tages convert the attribute value to a valid URL by adding a prefix and a suffix. Metatages can only be entered manually in the ORD file. Read the ORD specifications in the on-line documentation on www.orbitgis.com.

Any attribute can be specified as being a Maptip. Maptips appear on the map view as tooltips appear on the toolbar and menu. Maptips are shown for the selected dataset only and show the maptip attribute when hoovering above an object (point and hold still).

Maptips can be exported to Orbit FlashMap(r).

With this set of tools you can add and remove structural items from the Dataset.
WARNING: When doing so, you must realize that it will automatically affect ALL OBJECTS in the edited model of your dataset, and there is NO UNDO AVAILABLE. Save the Dataset before you alter the structure, or practise your changes on a copy.

To Remove : select a model and click 'Remove'. The model and all it's objects are removed.

To Add : set a Spatial Component type and Co-ordinate choice, then click Add. A new model is added.

WARNING: it's the user's responsibility to create structures that can be saved in the desired storage format. One should realize the restrictions that some storage formats have. Any structure can be saved in Orbit's own format OVF whenever required.

To Remove : select the Attribute Set and click 'Remove'. The Attribute Set and all it's values are removed from each object in the model.

To Add : select a model and click 'Add'. A new Attribute Set is created. Remember to add some Attributes to this Set to make it operational.

To Remove : select the Attribute and click 'Remove'. This field and all it's values are removed from each object in the mode.

To Add : select an Attribute Set or Attribute, type in a name and select a datatype, then click 'Add'.

To Change the system name of the Attribute: select the Attribute, type a new name and click 'Set'.
You can also alter the attribute's datatype at your own responsibility: Select the Attribute, change the datatype and click 'Set'. Orbit will try to change each value as good as possible.
Warning : there might be problems Orbit cannot resolve. In such case, you may be forced to shut down the program. Example : converting strings into numbers may work depending on the contents of the string attributes.

You may wish to have Attribute values calculated or constrained automatically. This is defined using rules. Rules are documented and stored in the Orbit Resource Descriptor file. Rules may apply to each single Attribute.

Select an attribute to see if a rule applies and if so which one.

You can specify that the value of an attribute must be calculated automatically using a formula. Formulas may apply to each single Attribute and are calculated in real time. Formulas can be extended using the Orbit API where you can develop your own rule.

All available formulas are listed in a listbox. Just select one. These attribute values will not be editable in the Object Inspector.

Attirbutes may be constrained t a list of valid values. You can enter all values or remove one from the list. When editing the value in the Object Inspector, a listbox will appear restricting the input to any of the entered valid values.

This rule applies to an Attribute set, constraining it to have one and only one row of attribute data. Remember that Orbit can manage to have many attribute rows as required by your data.