propsective changes branch

[Peter McCartney]

Peter McCartney (peter.mccartney at asu.edu)
Center for Environmental Studies
Arizona State University
480-965-6791 

> -----Original Message-----
> From: Chad Berkley [mailto:berkley at nceas.ucsb.edu]
> Sent: Wednesday, August 28, 2002 9:00 AM
> To: Peter McCartney
> Cc: Eml-Dev (E-mail)
> Subject: Re: propsective changes branch
> 
> 
> Hi Peter,
> 
> I don't have any major problems with the distribution section but I do
> have a few questions regarding your additions.
> 
> Do you intend to have two urls, one pointing to the actual connection
> and the other to the online documentation you need to make the
> connection?  I don't really understand your example url 
> below.  Did you
> mean to leave out the parameter values?
> 
> When you get the online documentation, does it have a structured
> format?  In other words, how do I know what I'm going to get when I
> follow that url?  

Im suggesting that for url structures that are either obscure or totally
made up, a pointer to its explnation would make it more useable by more
people. There IS no structured format for an sde connection -
alternately...there are MANY structure formats for others depending on what
software driver you might use. It all this discussion, none of you have
provided me with an example of a url string for SDE or a url string for an
sql database that doesnt require a user to parse the string, extract the
individual bits of information and pass them to the particular software they
intend to use. If we are going to force ourselves to use a single url
structure that isnt defined in eml, they we're going to have to accept that
the contents of that string are going to be non-standard. my sugession of a
second url was merely a way to provide indivuduals outside my own immediate
peer group the informatin needed to parse the particular string i make up.
for example, the following string is probably pretty opaque to you:

sde://mohave.asu.edu:5150?instance=ces_sde&catalog=USGSDRG
but if i give you a page that contains the following then anyone familiar
with sde would know how to parse that string and open a connection to sde
using any of a variety of tools that can do it - arcGIS, mapObjects,
arcExplorer, arcIMS, etc:

sde://host[:port]?[instance=]&[catalog=]

where host = the dsn name or ip address of the SDE service host computer
	port= the communication port the service listens to ( if missing,
this is asusmed to be 5150)
	instance = the name of the service. to use this name it must be
mapped to a tcp/ip port number in your 	services file.
	catalog= name of the database or catalog to connect to (this is not
supported by all services. If 	missing, the service will connect to the
default catalog).	

The only way you can use my string is 1) correctly guess what the parameters
are 2) call me or 3) read the above file if ive made it available and
pointed to it in my instance file. I supposed that in principle, there must
be a standard format for expressing url syntax like this that is machine
parsable, but i dont see what that gets you - in the absence of any
universal semantic standard for the parameter names, you're simply going to
have to read the page to understand that what im calling "catalog" is what
arcExplorer is prompting you for as "database"

ESRI added an element called SDE_connection to their profile of FGDC = its a
compound element with host,port,userid*,password*. Because the structure is
defined in the metadata standard, everyone knows exactly what the terms
mean. But you all dont want to make this information part of EML.


> It would be helpful to me if you could provide a sample 
> markup for, say,
> an SDE connection.
> 
> Thanks,
> chad
> 
> 
> 
> On Tue, 2002-08-27 at 11:45, Peter McCartney wrote:
> > Ok, ive checked in a working set of modules under the
> > EML_PROSPECTIVE_CHANGES_082602 branch. These files show:
> > 
> > 1) my proposed change to distribution to allow one to 
> provide a url string
> > that represents a connection rather than a discreet resource object,
> > identify the url as such with the function attribute, and 
> provide a url that
> > points to online documentation for a custom schema (eg 
> sde://hostname:port ?
> > instance=&database= )
> > 
> > 2) my proposed changes to address the LTER IM complaints about
> > protocol/project: these involved defining a new module 
> called eml-methods
> > which includes elements for quality control, sampling 
> description and
> > methodStep(s). MethodSteps includes pointers to related 
> sofware, datsets,
> > and instruments and a description which any combination of text,
> > eml-protocol, or eml-citation.
> > 
> > methods is imported optionally into dataset, entityBase and 
> attribute and
> > any previous links to protocol is removed. 
> > 
> > This solution leaves eml-protocol to be used only for 
> generic protocols that
> > we wish to publish as resources. There is still a flaw here 
> in that protocol
> > also defines a methodStep elment that differs from the one 
> in method. so the
> > name should be changed or perhaps protocol should just 
> import eml-method so
> > that all it does is add the resourceBase elements.
> > 
> > And Matt..thanks for the tip on winmerge...it was just what 
> i was looking
> > for.
> > 
> > Peter McCartney (peter.mccartney at asu.edu)
> > Center for Environmental Studies
> > Arizona State University
> > 480-965-6791 
> > 
> -- 
> -----------------------
> Chad Berkley
> National Center for 
> Ecological Analysis 
> and Synthesis (NCEAS)
> berkley at nceas.ucsb.edu
> -----------------------
> 
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