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.


RFC Template Version(1.0)
Submission DateOctober 6, 2008
Last ModifiedBruce Dechant Timestamp
AuthorChris Claydon
RFC Status(draft, proposed, frozen for vote, adopted, retracted, or rejected)
Implementation Status(pending, under development, completed)
Proposed Milestone2.1
Assigned PSC guide(s)Bruce Dechant
Voting HistoryOctober 15, 2008
+1Andy, Bruce, Haris, Jason, Paul, Tom


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.


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:

SETDISPLAYDPISets the display resolution in dots per inch
SETDISPLAYWIDTHSets the display width in pixels
SETDISPLAYHEIGHTSets the display height in pixels
SETVIEWSCALESets the required view scale
SETVIEWCENTERXSets the view center point x coordinate in mapping coordinates
SETVIEWCENTERYSets the view center point y coordinate in mapping coordinates
SHOWGROUPSSets the list of groups to display
HIDEGROUPSSets the list of groups to hide
SHOWLAYERSSets the list of layers to display
HIDELAYERSSets the list of layers to hide

The version for this request would be updated to 2.1.


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.


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.

Last modified 16 years ago Last modified on Oct 21, 2008, 9:22:33 AM
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