[MetaCRS] RE: New RFC -- Redesign of Datum Transform Engine (Norm Olsen)

[Norm Olsen]

Hello All . . .

I have added the following statement to the Implications section of the RFC.

"The proposed changes will not change the numeric results, nor will they change the performance of actual conversions.  The intent of these changes is to remove the dependence upon the WGS84 "pivot datum" model thus enabling more flexibility in defining datum conversions without having to change library code.  The performance of setting up a datum tranformation  (CS_dtcsu) will be negatively impacted, but the actual calulation of a datum shift will remain about the same."

Norm

-----Original Message-----
From: metacrs-bounces at lists.osgeo.org [mailto:metacrs-bounces at lists.osgeo.org] On Behalf Of Tom Fukushima
Sent: Wednesday, June 16, 2010 11:32 AM
To: metacrs at lists.osgeo.org
Subject: [MetaCRS] RE: New RFC -- Redesign of Datum Transform Engine (Norm Olsen)

Hi Norm,

For implications; I was wondering whether this will cause any change in the values produced from conversion?  For example, it would be good to state how much more accurate the new calculation would be; or if we don't know, to just say it is more accurate than before. Of course, if there is no change in the values that will be produced then I think that would be good to state explicityly as well.


Will these changes make transformations noticeably faster? Could it make a transformation 2x faster? Again, if we can quantify this, I think it would be good to add a statement about this to the implications section.


I'm assuming that with the new dictionaries, there will be a slowdown in initialization time of the libraries, but it will not be anything more than a few milliseconds at most.


Thanks
Tom



Date: Tue, 15 Jun 2010 15:38:45 -0700
From: Norm Olsen <norm.olsen at autodesk.com>
Subject: [MetaCRS] New RFC -- Redesign of Datum Transform Engine
To: "metacrs at lists.osgeo.org" <metacrs at lists.osgeo.org>
Message-ID:
	<DE08CCCA7394E04EAA6B31C916E5E1D76FC23065F6 at ADSK-NAMSG-02.MGDADSK.autodesk.com>
	
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Hello All . . .

I have written up an RFC describing a major overhaul to the datum transformation engine in CS-MAP.  Please review and forward any and all comments to me.

Thank you.

Norm

Norm Olsen
Software Engineer
Autodesk, Inc.
303-277-9967

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