<http://www.navcen.uscg.gov/pdf/lnms/2011-AOIPNC-International_Hydrographic_O rganization_Chart_Survey.pdf > Online: https://www.surveymonkey.com/s/IHODQWG IHO  survey re quality indicators for chart data The International Hydrographic Organization (IHO) is conducting a survey on the understanding and use of quality indicators for chart data. It is particularly interested in determining how the quality of chart data in S-101 ENCs could be better presented to the mariner. Responses from active mariners are particularly sought. Circular Letter 23-2011 (3/11/11). [demime 1.01d removed an attachment of type application/pkcs7-signature which had a name of smime.p7s]