In an effort facilitate a manageable modifications that may have to be made on an existing diagram, all the diagrams of the specification are stored in the 3GPP forge.
Within the specification that contains the diagrams, each diagrams has a caption: e.g. Figure 4.1-1. When the drawings are made in Visio, each page within the Visio file has a name that can be set to preferred name by the author, the default example: Page-1.
This annex provides a few guidelines to be followed in creating, naming, uploading, updating, and removal of those diagrams.
## Storage in the Forge and Naming Conventions
The diagrams for each deliverable are stored in a separate directory.
Each diagram is stored in a separate file with the figure number identifying the file name and the page that contains the diagram identifying the the version number of the specification that introduced the diagram. The filename should use the underscore character in place of spaces and periods.
For example:
- File name: `Figure_4_1-1.vsdx`
- Page name: `18.0.0`
In the above example, the diagram in the file named `Figure_4_1-1.vsdx` contains the figure that begins with the caption `4.1-1`. In the example, the diagram is introduced in version 18.0.0 of the specification and therefore, the page is named as 18.0.0.
When a CR with a new diagram is approved, after the new diagram is incorporated into the present document, the new diagram is uploaded using the above conventions.
## Changing a diagram
When an existing diagram requires a change, the CR author downloads the Visio file that contains the to-be-modified diagram, changes as per the needs, and either replaces the existing Page with the modified diagram or adds a new Page that contains the new diagram. In the latter case, the pre-modified diagram stays in the Visio File.
In any case, the Page that contains the modified diagram is named as per the convention listed above.
> NOTE: Retainig the pre-modified diagram in the Visio file may be a preferable approach in the case where the diagram is not modified in the release where the pre-modified diagram was introduced. However, retaining the pre-modified diagram in the Visio file is fine even if the modification is done in the same release.
Once the CR that has the modified diagram is approved and the modified diagram is introduced into the present document, the Visio file that contains the modified diagram is uploaded to the Forge replacing the existing Visio file.
## Removing a diagram
When an existing diagram needs to be removed, once the CR that removes the diagram is approved and the diagram is removed from the specification, the Visio file that contains the removed diagram is deleted from the Forge.
Alternatively, the CR author can download the Visio file that contains the pre-removed diagram, insert a new Page named after the version number of the specification that removed the diagram and upload the new Visio file replacing the existing Visio file. The new Page in this case cannot have a diagram because it does not
exist, and therefore, the new Page can say `VOID`.
This alternate approach may be preferred in the case where the diagram is not removed in the release where the pre-removed diagram was introduced. However, the approach may also be chosen even if the removal is done in the same release.
