[galeon] Fwd: CDM feature and point types docs

[Ron Lake]

I am most of the time

R

-----Original Message-----
From: Gerry Creager [mailto:gerry.creager at tamu.edu] 
Sent: March 13, 2008 10:31 AM
To: Ron Lake
Cc: Unidata GALEON
Subject: Re: [galeon] Fwd: CDM feature and point types docs

Howdy, Ron,

I think I can live with this derivation, and I agree with Keiran's more 
general description, as well.

As for clueless, it's a result of the schedule I keep.

gerry

Ron Lake wrote:
> HI Gerry:
> 
> I understand, but I think it is more a question of being observations
> that had some property which is point valued, rather than being points
> first.  Keiran's example is relevant as the observation could have
> multiple geometric characteristics associated with it.  I hope I did
not
> in any way imply you were "clueless"  - not at all my intention. I
think
> your viewpoint leads to more rigid structures for data representation
> and that was certainly the case in the domain of conventional
> planimetry.  
> 
> I would argue that no instrumentation can make point measurements -
but
> that will get us into a longer and likely not so useful debate.
> 
> R
> 
> -----Original Message-----
> From: galeon-bounces at unidata.ucar.edu
> [mailto:galeon-bounces at unidata.ucar.edu] On Behalf Of Gerry Creager
> Sent: March 13, 2008 10:03 AM
> To: Unidata GALEON
> Subject: Re: [galeon] Fwd: CDM feature and point types docs
> 
> Ron, et al,
> 
> Ah, but then it becomes a science-discipline semantics issue, too.
> 
> I do think in terms of making "point" observations of in-situ weather 
> data.  The observation is made at a fixed location, at a particular 
> finite time, and its geometric property is not a bounded region or 
> polygon, but a point.  Realizing there are gaps in this (wind is 
> measured at 10m above ground, temperature, humidity, pressure at 2 
> meters, precipitation at 1 meter, direct and diffuse solar radiation
at 
> nominally 2m but may vary, etc) the data are represented to end-users
as
> 
> being at a single spatial point.  Think of it as semantic collision 
> rather than assimilation.
> 
> And, while I don't think I'm completely clueless, I've spoken at the 
> TCs, and mentioned to you in the past, about "point features" in my
use 
> of WFS to represent observations, without discussion.
> 
> gerry
> 
> Ron Lake wrote:
>> Hi all:
>>
>>  
>>
>> Just a quick comment.  I think the idea of a "point feature" is 
>> misguided. The items covered in the list of point feature types is 
>> better covered as an observation feature or observation event.  The 
>> observation or observation collection then has geometric
> characteristics 
>> such as where the observer was located, or where the observations are

>> located.  I am generally opposed to the idea of defining features by 
>> their geometry properties since this has the semantics backwards.  No

>> instrument can make "point measurements" - so the items are
> observations 
>> first and these observations then have geometric properties (like 
>> location or estimated location).
>>
>>  
>>
>> Cheers
>>
>>
>> Ron
>>
>>  
>>
>> *From:* galeon-bounces at unidata.ucar.edu 
>> [mailto:galeon-bounces at unidata.ucar.edu] *On Behalf Of *Ben Domenico
>> *Sent:* March 13, 2008 9:15 AM
>> *To:* Unidata GALEON
>> *Subject:* [galeon] Fwd: CDM feature and point types docs
>>
>>  
>>
>> Hi all,
>>
>> Please note the DRAFT documents John Caron has created on CDM 
>> data/feature types.  These are in the early stages of discussion and 
>> revision so please keep in mind that this is all very much SUBJECT TO

>> CHANGE.   But the topics covered are important to GALEON so we need
to
> 
>> give them some thought.
>>
>> -- Ben
>>
>> ---------- Forwarded message ----------
>> From: *John Caron* <caron at unidata.ucar.edu
> <mailto:caron at unidata.ucar.edu>>
>> Date: Mon, Mar 10, 2008 at 1:19 PM
>> Subject: CDM feature and point types docs
>> To: techies <techies at unidata.ucar.edu
> <mailto:techies at unidata.ucar.edu>>
>>
>> new draft CDM Feature Types:
>>
>> http://www.unidata.ucar.edu/software/netcdf-java/CDM/CDMfeatures.doc
>>
>> new doc CDM Point Feature Types:
>>
>> http://www.unidata.ucar.edu/software/netcdf-java/CDM/CDMpoints.doc
>>
>> feedback appreciated
>>
>>  
>>
>>
>>
>
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-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
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