MapGuide RFC 56 - Add additional map commands to GETDYNAMICMAPOVERLAYIMAGE
This page contains an change request (RFC) for the MapGuide Open Source project. More MapGuide RFCs can be found on the RFCs page.
Status
| RFC Template Version | (1.0) |
| Submission Date | October 6, 2008 |
| Last Modified | Bruce Dechant Timestamp |
| Author | Chris Claydon |
| RFC Status | (draft, proposed, frozen for vote, adopted, retracted, or rejected) |
| Implementation Status | (pending, under development, completed) |
| Proposed Milestone | 2.1 |
| Assigned PSC guide(s) | Bruce Dechant |
| Voting History | October 15, 2008 |
| +1 | Andy, Bruce, Haris, Jason, Paul, Tom |
| +0 | |
| -0 | |
| -1 | |
| Abstain | Bob |
Overview
The proposal is to add additional, optional parameters to the GETDYNAMICMAPOVERLAYIMAGE HTTP request format to allow setting the map view state. These parameters are already supported by the GETVISIBLEMAPEXTENT and GETMAPIMAGE HTTP request formats.
Motivation
The MGOS AJAX and Fusion viewers currently make (at least) two HTTP requests to render each new map image - one to GETVISIBLEMAPEXTENTS, which is used to set the current map view, and one to GETDYNAMICMAPOVERLAYIMAGE. The first request returns the extents of the map after the view state parameters have been applied. But in some cases this information is not required, and the two calls could easily be combined into one. This would provide increased efficiency and scalability.
Proposed Solution
The proposal is to add support for the following parameters to the GETDYNAMICMAPOVERLAYIMAGE HTTP request format:
| SETDISPLAYDPI | Sets the display resolution in dots per inch |
| SETDISPLAYWIDTH | Sets the display width in pixels |
| SETDISPLAYHEIGHT | Sets the display height in pixels |
| SETVIEWSCALE | Sets the required view scale |
| SETVIEWCENTERX | Sets the view center point x coordinate in mapping coordinates |
| SETVIEWCENTERY | Sets the view center point y coordinate in mapping coordinates |
| SHOWGROUPS | Sets the list of groups to display |
| HIDEGROUPS | Sets the list of groups to hide |
| SHOWLAYERS | Sets the list of layers to display |
| HIDELAYERS | Sets the list of layers to hide |
The version for this request would be updated to 2.1.
Implications
The code to parse and apply the view setting parameters already exists in the MG web tier. Implementing it for GETDYNAMICMAPOVERLAYIMAGE is therefore very straightforward. No changes are required in the MG server code to support the change.
Test Plan
Web tier unit tests should be added to test the new parameters.
Funding/Resources
Autodesk to provide resources to implement web tier and AJAX Viewer changes. Fusion viewer updates can be made by the appropriate parties following the web tier updates.
