[fdo-internals] Dropping off PSC

Leaf Li leaf.li at autodesk.com
Tue Nov 2 04:06:37 EDT 2010

I will try to summarize all of my changes to OGR and write one GDAL RFC  document for your review. Actually those are exactly MITAB issues that I met.

1.  As for field type, I have a little different opinions. I found you already write one GDAL RFC to address 64bit integer.

Why do you think it is a problem to add int16, float, decimal? If the field type is int16, GDAL expose it as int32. It must there are some issue to update filed value with one integer value larger than maximum value of int16. For me, I think the major issue is efforts. I don't know what are exactly your concerns. However, providing some sort of additional hints mechanisms around attribute fields is a good idea.

2. For geometric type, I add curve line, curve polygon, multiple curve polygon. However, I didn't finish it in MITAB and MapInfo FDO Provider. So no surprise that you didn't find the corresponding code. However, I am not sure whether it is really necessary to add it in OGR because FDO supports circular curve only for now.

3. I like to be one contributor of GDAL/OGR. So does Aleck.

4. My biggest concerns is I have to handle all of OGR drivers once I any changes to OGR API. It isn't one trivial task. If I am not busy in next several months, I can finish it using my spare time. Otherwise, I have to check whether Autodesk will provide funding for it.

Leaf Li

-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Frank Warmerdam (External)
Sent: Monday, November 01, 2010 11:54 PM
To: FDO Internals Mail List
Subject: Re: [fdo-internals] Dropping off PSC

Greg Boone wrote:
> Hi Daniel, Frank,
> Is it possible for one or both of you to take a look at the MITAB 
> changes that Leaf and Aleck made, and offer guidance on how we can 
> move towards having the proposed changes, or a variation of the 
> changes, integrated into the MITAB trunk?
> http://code.google.com/p/groundnut/
> If you can outline what has been done vs. what needs to be done, and 
> propose ideas on how to get from here to there, we can determine if 
> the community can find the resourcing required to make up the delta.


Well, this isn't the most convenient form for us to analyze.  I'll leave MITAB to Daniel.  Skimming through the revision set and examining the text I was able to identify the following revisions for adding new field types.


The goal seems to be to add many specific field types for different sizes of integer, and floating point value.  I fundamentally disagree with this change, and prefer to let the width and precision values act as clues with regard to field size.  So, I am doubtful such changes could make it into GDAL/OGR without an override of my vote on the PSC.

Boolean is the one case that I would be more accepting of, though I am also dubious about the value of treating this as other than an integer.

On the other hand, it might make sense to provide some sort of additional hints mechanisms around attribute fields in OGR for applications that really want to know details about the fields - like FDO.  Alternatively this might be an area where an FDO Mapinfo provider would "go around OGR"
to make a direct MITAB call to get details, or provide them during field creation.

I presume somewhere there are changes related to new geometry types for curves but it after scanning 380 revision texts I was unable to identify them.

The normal procedure would be for the person needing new features to write an RFC describing what they need, why, how it will be accomplished and what issues they foresee.  I realize this is a substantial process and that with the provider already in existance the chances of there being resources to pursue the various changes via a the consensus process will be small.

PS. It is clear Leaf has done some really great work, and plumbed deep depths in MITAB and OGR.  I would love to harness him as a contributor!

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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