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The IICWG Ad Hoc Format Working Group

SIGRID-3: A New WMO format for Ice Chart Archival and Exchange: Status and Remaining Issues IICWG-4, April 7-10 St. Petersburg, Russia. The IICWG Ad Hoc Format Working Group. The IICWG Ad Hoc Format Working Group.

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The IICWG Ad Hoc Format Working Group

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  1. SIGRID-3: A New WMO format for Ice Chart Archival and Exchange:Status and Remaining IssuesIICWG-4, April 7-10St. Petersburg, Russia The IICWG Ad Hoc Format Working Group

  2. The IICWG Ad Hoc Format Working Group From the Arctic and Antarctic Research Institute, Vasily Smolyanitsky, Yuri Scherbakov, and Viktor Porubaev; From the Canadian Ice Service, Richard Chagnon and John Falkingham; From the Danish Meteorological Institute, Henrik Steen Andersen and Morten Lind; From the U.S. National Ice Center, Jonathan Hasse, Doug Lamb, and Paul Seymour; (lead on SIGRID-3 Technical description document) From the U.S. National Snow and Ice Data Center, Florence Fetterer.

  3. GDSIDB SIGRID-3 Format Progress • GDSIDB Vision– to preserveice chart data in archives, and to make digital versions of ice charts available for research use • GDSIDB at AARI:http://www.aari.nw.ru/gdsidb/ • GDSIDB at NSIDC:http://nsidc.org/noaa/gdsidb/ • ETSI-1 and GDSIDB - IX, Buenos Aires, 21-25 October 2002: IICWG ad hoc format team presented proposed SIGRID-3 format to Expert Team on Sea Ice • Need to make final edits (Wednesday 9 AM IICWG-4 Technical Breakout mtg) • V. Smolyanitsky will submit final draft and recommendations for formal approval and publication by WMO Secretariat, through JCOMM (M. Krasnoperov) • We anticipate a later revised version, or addendum • Supplementary material, examples on GDSIDB web site • DMI, NIC (and CIS?) will begin producing charts for archive in SIGRID-3 as soon as format is finalized

  4. Some Characteristics of SIGRID-3 • Based on ESRI shapefile format • Each chart will have at least 4 files - .shp (polygon shapes), .dbf (attributes), .shx (index) and .met (metadata) • File naming convention will include identifiers for issuing country/organization, geographic region and date • Recommended projection will be polar stereographic true at 60N with central meridian at 180 using the WGS84 spheroid • Ice attributes will follow existing WMO SIGRID codes and field names • Metadata will follow the FGDC metadata standard, and be in XML if possible. References - Chagnon. 2001. CIS/NIC Proposed SIGRID 3 Format. CIS Informal Paper, Canadian Ice Center, Ottawa. Hasse. 2001. National Ice enter Shapefile Format Options. NIC Informal Paper, 24 October, National Ice Center, Washington, DC.

  5. SIGRID-3 Format Information and Tools Online: http://nsidc.org/noaa/iicwg/ahfwg_discussion.html http://nsidc.org/noaa/gdsidb/formats.html http://nsidc.org/noaa/gdsidb/s3development • SIGRID-3 shapefiles examples • Technical description of shapefiles • Links to info on xml editors…. Here: Arc Explorer (free software for viewing shapefiles [and FGDC metadata?] Sample shapefiles from DMI and NIC Metadata Tools Survey SIGRID-3_Draft_9 Paper copy of WMO SIGRID format

  6. Remaining Issues Before SIGRID-3 Document is Finalized • (work we have to do today) • Section 2.3 on Required database fields – need to distinguish between info needed to make dBase fields on one’s own, and info needed by ESRI software user. • Section 2.4 on “dummy” or “missing” variable – need clarification. SIGRID uses “99” for undetermined or unknown. This does not cover all cases.

  7. Remaining Issues Before SIGRID-3 Document is Finalized • (work we have to do today) • Any issues brought by J. Falkingham for R. Chagnon? • Section 2.4 on “dummy” or “missing” variable – need clarification. SIGRID uses “99” for undetermined or unknown. This does not cover all cases. • Page 3 – [….], Page 7 – [….], Page 9 – [….] • Other issues?

  8. Other Remaining (non-critical) Issues • Table 2 – Can we create a more informative XML example? Either for document, or for website –HA • When not an ice polygon (e.g. have L, W, N, or S in poly_type column, are other columns filled with –9? • Metadata -- Can we create a “master” dtd and stylesheet? Any volunteers?

  9. Other Remaining Issues • Metadata -- Need lists of acceptable keywords. Perhaps each center proposes their own. Any volunteers? • Extension of format for points and lines. Yuri? • Proposal by V. Porubayev for alternative coding of Stage of Development. (part of Proposals for a new WMO Sea Ice Nomenclature – terms, symbols and code tables?) • Other non-critical issues?

  10. Action Items • ???

  11. BACKGROUND

  12. Current Formats GDSIDB formats • SIGRID (Proposed 1981, Thompson) • SIGRID-1 (Adopted by WMO, 1989) • SIGRID-2 (Adopted by WMO, 1994) • SIGRID-3 (Proposed vector format) Some other digital ice chart formats • Contour • e00 (proprietary GIS system export format) • EASE-Grid • shapefile http://nsidc.org/noaa/gdsidb/formats.html for more info

  13. Why a new format? For accuracy, and to make charts easier to create • SIGRID (Sea Ice Grid) first proposed in 1981 as GDSIDB archive format. SIGRID data archives are kept at AARI and at NSIDC • Combination of grid (with min. spacing of 15’) and text encoding of ice chart information • Most ice services no longer regularly submitting data to GDSIDB in SIGRID. (JMA’s continuing SIGRID submissions are noted with gratitude) • Loss of accuracy and resolution from original charts • Research community must reformat before using SIGRID files • Many ice services use GIS for chart production. Therefore, we recommend a GIS vector file output format for "SIGRID-3". • GIS output files: easy for ice centers to produce; archive data in vector format. • Vector files can be re-projected or re-scaled without loss of information. If desired, conversion to raster can take place at the archive center.)

  14. Fully Utilized Egg Code: 4-6/3200/7./4.1.7/1/~9 CC/CaCbCc/So/SaSbSc/Sd/FpFp SIGRID: CT46CA309399CB209199CC018799CF1999CN95CD81 Some SIGRID-1,2 Characteristics

  15. SIGRID-3 Objective • Facilitate the regular submission of ice charts in digital form to the GDSIDB by defining a new SIGRID-3 archive format based on ESRI shapefile format. • Archive charts in a format that captures all the information in the original charts. A vector format is required.

  16. History • June 2000 -- NIC and NSIDC proof of concept project to convert ESRI ArcInfo export format E00 files to gridded format completed • July 2000 -- ESRI "Shapefiles" export format suggested as an alternative output format. (E00 is an ESRI proprietary format, shapefiles are an open format.) ArcView shapefiles are a simple, non-topological format for storing the geometric location and attribute information of geographic features. • October 2000 -- at IICWG 2, an ad hoc format working group presented a proposal for shapefiles. Ice services endorsed the proposal, pending evaluation. • March 2001 -- DMI year 2000 Greenland ice charts sent in shapefile format to NSIDC. • April 2001 -- CIS and NIC created sample charts as shapefiles • June 2001 -- At JCOMM meeting, GDSIDB experts endorse shapefiles as an ice chart archive format, make recommendations on its implementation • August 2001 -- Sample DMI charts and background information posted to IICWG web site, comments on the DMI shapefile format solicited.

  17. History • October 2001 -- CIS/NIC shapefile based format proposed for SIGRID-3. Format was developed at the September U.S./Canada Joint Ice Working Group meeting. • November 2001 - CIS/NIC shapefile format and DMI shapefile format discussed by Ad Hoc Format Working group at Tromsø IICWG 3 meeting. Representatives of Sweden, Finland and the Baltic states do not use Arc software at present but endorsed the recommendation that shapefiles with FGDC format metadata be adopted as the archive format for ice service charts. They anticipate moving in the direction of GIS tools and shapefile production. NIC (D. Lamb) takes lead on coordinating development of format with CIS and other services for proposal to JCOMM • May - Sept 2002 - Document for proposed SIGRID-3 in development, led by NICs J. Hasse • August 23 2002 - telecon to finalize details of proposed format, AARI, CIS, DMI, NIC, NSIDC • October, 2002 - presentation to ETSI, Buenos Aires meeting.

  18. Advantages of SIGRID-3 • Vector files can be re-projected or re-scaled without loss of information • Vector files are easier for most ice centers to produce • Conversion to raster (at grid size of choice) can take place at GDSIDB archive center • Non-proprietary format means even those centers that do not use commercial GIS packages can produce Shapefiles

  19. NIC charts -- one example

  20. DMI charts -- one example Sea ice concentration from satellite passive microwave data Sea ice concentration from DMI shapefiles

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