>To: "Mitch Gordon" <mgordon@mail.arc.nasa.gov>
>From: Amara Graps <amara@amara.com>
>Subject: RE:  PPS Peer review
>Cc: Amara.Graps@mpi-hd.mpg.de, SHOWALTER@ringside.arc.nasa.gov,
>        nicholson@astrosun.astro.cornell.edu
>
>
>Evaluation of PDS PPS Data Archive
>
>by Amara Graps
>amara.graps@mpi-hd.mpg.de or amara@amara.com
>Heidelberg Cosmic Dust Group
>Max-Planck-Institut fŸr Kernphysik
>Heidelberg, Germany
>August 2002
>
>
>The materials that I used to evaluate the CD is mostly contained in
>eleven Voyager notebooks (Six for Saturn dated June 1982 to April
>1986, and five for Uranus dated January 1986 to February 1995) and
>one box of file folders. Since I have this material, and I've
>transported it with me these last 20 years, and the information is
>unique, I was compelled to use it.  Well and good, but unfortunately
>the time to evaluate took longer than I thought, which I didn't know
>until I got into it, and began checking files (discovering that a
>large number of star calibrations were from me). I needed about a
>week to do this evaluation properly, and so now this is the result.
>
>---------------------------------------------------------------------
>Question
>
>Mark, in December 1999, I wrote you notes regarding the Saturn star
>calibration data files, and I said in my letter that I would xerox
>pages from my notebooks for you. Did I do that? If not, do you still
>want it? I marked those (~20) pages, in the last week.

Yes, files were provided.

>
>For Near Future
>
>If you have questions or you need more information, which  I have
>with me in my notebooks, I suggest asking before October 2002,
>because I will moving (Heidelberg->Rome) in November/December, and
>for some months my notebooks will be in storage and might not be
>accessible.
>
>---------------------------------------------------------------------
>
>I have organized this evaluation in the following way, with the most
>emphasis on the data contents.
>
>Evaluation of:
>
>* Data Contents                     * details in separate attachment
>* Ease of Use
>* Given Tutorial (DOCUMENT/TUTORIAL.TXT)
>* Working through a past example     * details in separate attachment
>
>=======================================================================
>
>Evaluation of:
>
>-------------------------------------------------------------------
>* Data Contents
>-------------------------------------------------------------------
>
>Details are provided in the accompanying file:
>'DetailedEvaluation.txt'
>
>SUMMARY:
>
>I think that the data on this disk is very well-organized, the
>directory structure is logical and I like the file naming convention
>because it is sensible and flexible. The data files which were
>formatted ASCII were easy to examine, extract and manipulate, however
>the binary formatted files proved to be a problem for me. I am not
>familiar with OAL, and I don't know if this is the normal way to
>extract files such as those binary files. If it is, then I am behind
>the times, and I should get up to speed on this approach. Instead, my
>attempt to read  and extract some binary data was with an edited (for
>Unix) version of one of the supplementary programs provided in the
>'Processing Software' portion of this disk, and, unfortunately, the
>read failed, and I don't know why.
>
>The labels for each of the data files was easy to understand, the
>'Contents' file for each directory was useful, important (thank you)
>and also easy to understand. All of the processing steps illustrating
>the procedure from raw to 'final' product was clear.
>
>In several places where I could check the values of the data, I did. I
>found one discrepancy with the background values of the PS1CO1.TAB
>file. Since I thought the discrepancy might be due to differences
>between JPL and LASP in their PROCCS record numbering, to check that,
>I looked at a familiar region, the Encke Gap, in order to see if the
>background that you have stored is the proper one. It looked OK. I
>might be useful to mention somewhere that the PROCCS numbering changed
>? (for viewers like me who used the old JPL numbering)

I have noted the change in record numbers near the top of
EDITDATA/DATAINFO.TXT.

>
>I was very happy to see my favorite Saturn GS-3 mode stellar
>occultation (that part at the end of the main OC-1 mode) become part
>of the standard data archive. I didn't know that I was the only owner
>of that data, and seeing it described on this disk in the way that it
>was, was a pleasant surprise.
>
>I was disappointed to not see the any of the Saturn PPS 0.1 km 0.2 km
>0.5 km resolution in ASCII form stored, even though I understand that
>these files could be very large, and it is likely expect the casual
>user of EASYDATA would not be interested in these high resolution
>files.

I agree that there is no reason to exclude 0.2-km and 0.5-km Saturn
occultation data, so these files has been added to the EASYDATA
directory tree. I did not include 0.1-km sampling because that exceeds
the intrinsic sampling of some of the data.

>
>I am not sure that the given geometry (range) information is accurate
>enough, since we  we are given one range per record, and must
>interpolate between the 600 points in a record.

The tools we use carry out cubic spline interpolation, which is
extremely accurate for interpolation across 600-point records. Even
linear interpolation is unlikely to yield errors of more than ~1
meter. This is now noted in the text of GEOMETRY/GEOMINFO.TXT.

>
>I didn't see several 1981 star calibration files (that I thought
>existed) for the stars alpha Lyr, an alpha Cma, and an alpha Leo.

I did not find any other calibration data among the files you
provided. I also checked with Karen Simmons but she was unable to
provide additional calibration files.  If any turn up, we can always
create a supplemental archive.

>
>I have provided more information if that would be useful. I have given
>more information for some files in the RAWDATA directory. In
>appendices to 'DetailedEvaluation, I have given Uranus PPS inferred
>PPS background and star values (publ in Graps et al., 1995), Uranus
>PPS published calibration and equivalent depths (to compare with
>above), more limit cycle information, a LWE memo of background at
>Uranus due to off-axis light, and notes for delta Sco star calibration
>raw counts as a function of electronics temperature.
>
>-------------------------------------------------------------------
>* Ease of Use
>-------------------------------------------------------------------
>
>
>SUMMARY: The binary data extraction was a problem for me, otherwise I
>give the highest marks for ease of use of this CD.
>
>* Given Tutorial (DOCUMENT/TUTORIAL.TXT)
>
>SUMMARY: I thought that this file would be an example "walk-through"
>to extract data, and it isn't. However, it is the most important file
>after 'AAREADME.TXT', and gives the most important information that I
>think a user needs.
>
>-------------------------------------------------------------------
>* Working through a past example
>-------------------------------------------------------------------
>
>Uranus ring data extraction and manipulation
>
>Task: Extract three cuts of the Epsilon ring, and compute the
>eccentricity of the outer edge of the ring using radiuses and
>longitudes. (roughly)
>
>Answer:  eccentricity = 9.7 E-03
>
>(Uranus Notebook #1,pg. 26 = eccentricity = 8.24622E-03,
>Elliot&Nicholson, _Planetary Rings_ = 7.94E-03)
>
>So then, same magnitude as 'right answer', but off, due to only
>working with very few significant digits, and lower resolution of the
>cuts used here, especially BPI. This can be improved using closer-to
>the highest resolution data.
>
>---------------------------------------------------------------------
>
>Giving subjective evaluation numbers, from scale of 1 to 10:
>
>* Data Contents  9.5 (weighted most)
>* Ease of Use  9.0
>* Given Tutorial (DOCUMENT/TUTORIAL.TXT) 7.0
>* Working through a past example    9.0
>
> --> Very Good
>
>Amara Graps
>
>-- 
>
>************************************************************************
>Amara Graps, PhD             | Max-Planck-Institut fuer Kernphysik
>Heidelberg Cosmic Dust Group | Saupfercheckweg 1
>+49-6221-516-543             | 69117 Heidelberg, GERMANY
>Amara.Graps@mpi-hd.mpg.de    * http://www.mpi-hd.mpg.de/dustgroup/~graps
>************************************************************************
>I'M SIGNIFICANT!...screamed the dust speck. -- Calvin
>
>Attachment converted: Data:WorkingPastEx.txt (TEXT/R*ch) (00044250)
>Attachment converted: Data:DetailedEvaluation.txt (TEXT/R*ch) (00044251)