= !MapGuide RFC 162 - Enhanced coordinate system capabilities in mapagent =

This page contains a change request (RFC) for the !MapGuide Open Source project.  
More !MapGuide RFCs can be found on the [wiki:MapGuideRfcs RFCs] page.


== Status == 
 
||RFC Template Version||(1.0)|| 
||Submission Date||12 July 2017||
||Last Modified||12 July 2017||
||Author||Jackie Ng||
||RFC Status||draft||
||Implementation Status||not started||
||Proposed Milestone||||
||Assigned PSC guide(s)||||
||'''Voting History'''||||
||+1||||
||+0||||
||-0||||
||-1||||
||Abstained||||
 
== Overview ==

This RFC proposes to enhance the coordinate system capabilities of the mapagent

== Motivation ==

MapGuide has one of the most powerful coordinate system transformation libraries (CS-Map) with support for several thousand different coordinate systems out of the box.

Yet, as a MapGuide HTTP client application none of these transformation capabilities are ever exposed to the mapagent. To tap into coordinate transformation requires using the MapGuide Web API and thus custom server-side code that a HTTP client application would have to call into.

== Proposed Solution ==

This RFC will add the following enhancements to the mapagent

=== Batch Coordinate Transformation ===

We'll add a new mapagent operation for batch transformation of coordinates from one coordinate system to another

|| '''Name''' || '''Value'''  || '''Required''' || '''Description''' ||
|| OPERATION || CS.TRANSFORMCOORDINATES || Yes || Operation to execute ||
|| VERSION || 3.3.0 || Yes || Operation version ||
|| CLIENTAGENT || text || Optional || Descriptive text for client ||
|| COORDINATESYSTEM || string || Yes || The CS-Map code describing the coordinate system of the input coordinates ||
|| TRANSFORMTO || string || Yes || The CS-Map code of the coordinate system to transform the input coordinates to ||
|| FORMAT || string || Yes || {{{text/xml}}} for XML, {{{application/json}}} for JSON ||
|| CLEAN || 1/0 || Optional || If requested format is {{{application/json}}}, returns a clean JSON structure per [wiki:MapGuideRfc158] ||

The response matches the new {{{CoordinateList-3.3.0.xsd}}} schema

{{{
TBD
}}}

=== Transformation support for any mapagent operation that returns geometry ===

Any operation that returns geometry data will now have an optional {{{TRANSFORMTO}}} parameter, which if set (to an appropriate Mentor CS code) will instruct the supporting operation to transform the geometry result to the specified coordinate system.

The following operations will have a new {{{3.3.0}}} version that supports the optional {{{TRANSFORMTO}}} parameter:

 * {{{SELECTFEATURES}}}
 * {{{SELECTAGGREGATES}}} (if a geometric aggregate expression is found. eg. {{{SpatialExtents}}})

== Implications ==

These are new API additions

== Test Plan ==



== Funding/Resources ==

Community