[Esip-preserve] Fwd: ISO/TC 211: preservation

Wolfgang Kresse via Esip-preserve esip-preserve at lists.esipfed.org
Thu Jul 17 13:24:43 EDT 2014

Bruce and Ted,

I thank you for the comments that help to understand our own (ISO's) 
position and allow a more sensitive definition of the scope.

ISO/TC 211 claims to be responsible for all geospatial data. Therefore, 
it is helpful to know about difficult terrain such as meteorology and 
oceanography that may not be covered by the intended standard.

The vertical component as done in the ISO 19111 presently gets some 
refinement by a new project about NTv2.

The links to glossaries are very welcome.

The term resolution may require a general discussion within the ISO/TC 211.

Algorithms and ancillary data will be added to the WD in an appropriate way.

Again, many thanks!

Ted, how should we formalize the flow of information between ESIP and 
ISO in the future?

With best regards

Am 16.07.2014 16:31, schrieb Bruce Barkstrom:
> Some care will be needed in creating a standard for all geospatial
> data.  Here are a few caveats:
> 1.  Vertical coordinates are not simple.  See
> <http://mtp.mjmahoney.net/www/notes/altitude/altitude.html>
> which treats both the relationship between geometric altitude (usually
> abbreviated z) and geopotential
> altitude (Greek Phi) and the dependence of various formulae on the shape
> of the Earth.  While lidars
> and radars use time-of-flight to get fairly direct geometric altitudes,
> radiosondes and passive IR sensors
> reduce data to geopotential.  The important point is that to convert
> from geometric altitude to geopotential
> for a particular vertical profile, the data source needs to record the
> temperature and humidity profile (meaning
> values of temperature and humidity as a function of barometric pressure).
> Meteorologists and atmospheric scientists use geopotential in their
> forecasting models because
> winds would flow along geopotential surfaces without changing potential
> energy.
> For oceanic fields, the relevant ancillary vertical profiles are
> temperature and salinity.  In addition, oceanic models
> (such as the one that MIT has) can use sigma coordinates for the
> vertical.  Sigma normalizes the pressure
> fields so that this variable is 1 at the bottom of the column and 0 at
> the top.  To convert to geopotential
> or depth in the ocean, the data need to have the pressure at the bottom
> of the column, an additional
> piece of data to include.
> Of course, if the primary interest is in just the solid surface of the
> Earth, this may not be a problem
> as long as the interested parties want geometric altitude.  However,
> hydrologists will need geopotential
> because water can naturally flow "uphill" if the geopotential is lower
> further from the Earth's center.
> GPS data does not give geopotential, so some care in documentation of
> coordinates is in order.
> 2.  It would seem to be sensible to consult standard glossaries for
> terms before finalizing the data
> dictionary.  For example, NOAA's National Weather Service has an on-line
> glossary at <http://w1.weather.gov/glossary/>
> The American Meteorological Society has another at
> <http://glossary.ametsoc.org/wiki/Main_Page>.
> The World Meteorological Organization also maintains an on-line glossary
> that appears to be a bit
> fancier: <http://wmo.multicorpora.net/MultiTransWeb/Web.mvc>.  If you
> just try a Google search
> for WMO Glossary, the first URL gives a list of organizations.
> 3.  In dealing with basic data sources, it would be helpful to remember
> that instruments and platforms
> are not standardized.  Some instruments, such as radiosondes, are mass
> produced.  In this
> case, the vendor usually supplies manuals with operation and calibration
> procedures as well as algorithms.
> However, aircraft and satellite data management systems for research
> measurements are usually one-off
> systems.  Likewise, research instruments are one-off systems.  Such
> one-off systems do not have a
> standardized set of operational modes, formats for exceptions, and types
> of housekeeping data.  Basically,
> instruments and platforms would have to use the same physics and
> electronic parts in the same assemblies
> and designs if we were to try to get common exceptions and causes of
> anomalous conditions.
> Research teams may also introduce specialized data codes for
> observational conditions.  For example,
> radiosondes ascending through cold cloud layers may collect ice on the
> sensing elements.  Observers
> may differ in their opinions about how to detect icing and how to
> annotate or edit the data record
> to indicate the condition.  In satellite systems, the satellite may
> require instruments to go into
> "safe" mode when they are conducting orbital adjustments or start
> tumbling.  Likewise, instruments
> may have special calibration modes that have different sequences of data
> collection.
> 4.  As a specific note on vocabulary, the term "resolution" in the data
> dictionary may not be defined
> in accord with the existing technical standards for the measurements.
> Wikipedia's disambiguation
> page on this term may be a helpful place to start
> <http://en.wikipedia.org/wiki/Resolution>.  The page
> on "image resolution" at <http://en.wikipedia.org/wiki/Image_resolution>
> is probably not as well documented
> as it should be.  The article at
> <http://en.wikipedia.org/wiki/Accuracy_and_precision> is closer to the
> technical standards.
> It has been known for a long time that in many cases (including optical
> imaging systems) that
> there is a tradeoff between precision and resolution.  One of the
> classic papers in this area
> is Backus, G. and Gilbert, F., 1970: Uniqueness in the inversion of
> inaccurate gross Earth data,
> Phil. Trans. of the Roy. Soc., 266, No. 1173, pp. 123-192.  The authors
> use the term "resolving
> power" instead of resolution, but it is clear that one should expect
> that the more local precision
> (or reduction in uncertainty) one seek, the lower the resolving power of
> the resulting data.
> 5.  In preserving data, it's clear that to use data sensibly,
> researchers need to understand what
> they're working with.  Because most Earth science data involve complex
> physics and math,
> there must be some documentation that provides the derivation of the
> algorithms and the
> models of the instrument physics.  Likewise, there needs to be some
> storage of ancillary
> data, such as physical constants (including the spherical harmonic
> coefficients that represent
> the shape of the geopotential) and calibration data.  It isn't clear
> whether this documentation is
> "metadata" or some other kind of material.  This material probably needs
> to be worked into
> web sites in a way that can be used by people with different
> backgrounds, perhaps as tutorials.
> Bruce R. Barkstrom
> On Tue, Jul 15, 2014 at 4:00 PM, Ted Habermann via Esip-preserve
> <esip-preserve at lists.esipfed.org
> <mailto:esip-preserve at lists.esipfed.org>> wrote:
>     Wolfgang,
>     The train ride worked out quite well. I was the only person in my
>     cabin, so the 4-person cabin was great. I did actually get some
>     sleep… Thanks so much for your help!
>     I am forwarding the preservation draft to the preservation cluster
>     of the Earth Science Information Partners. This is a diverse group
>     of scientists from NASA, NOAA, and other organizations that are
>     interested in preservation. They are a great group that have thought
>     about these problems quite a bit. I did note that you still seem to
>     refer to OAIS as being related to satellite imagery. I suspect that
>     most of these people think of it as being broader than that.
>     ESIP - Wolfgang is a friend from Germany that is writing a draft
>     preservation proposal for ISO TC 211 building on the OAIS. I spoke
>     with him during a recent ISO meeting about preservation and said I
>     would connect him with you…
>     Thanks to all,
>     Ted
>     _______________________________________________
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Prof. Dr.-Ing. Wolfgang Kresse
Neubrandenburg University of Applied Sciences
Faculty of Landscape Sciences and Geomatics
Brodaer Strasse 2
17033 Neubrandenburg

Tel.  +49 (0) 395 5693 4106
Fax   +49 (0) 395 5693 4999
E-mail kresse at hs-nb.de

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