<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><h3 style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><span style="font-size: 14px; font-weight: normal;" class="">Dear DAL,</span></h3><div class=""><span style="font-size: 14px;" class="">I have a question regarding the FORMAT input parameter described in SIAv2.0:</span></div><div class=""><h3 style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>2.1.17 FORMAT</h3><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>The FORMAT parameter specifies response format(s) (the access_format column from the ObsCore [7] data model). This column describes the format of the response from the access_url (see <a href="http://www.ivoa.net/documents/SIA/20151223/REC-SIA-2.0-20151223.html#bkmRefHeading200962138146524" rel="noreferrer noopener" target="_blank" title="http://www.ivoa.net/documents/SIA/20151223/REC-SIA-2.0-20151223.html#bkmRefHeading200962138146524" tabindex="-1" class="">3.1.3</a>) so the values could be data file types (e.g. application/fits) or they could be the DataLink [8] MIME type. </p></div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">It is unclear to me how to read that.</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">I have two possibilities in mind:</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><br class=""></div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">1) The FORMAT input param is used to add a constraint onto the access_format, e.g.:</div><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""> ...&FORMAT=application/fits</p><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""> gets translated into a constraint like: </p><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""> SELECT ... WHERE access_format = 'application/fits</p><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">but that does not seem to have much sense, as some data providers might have decided that access_format in the ObsCore table is always the datalink mime type, delegating and delaying the specification of the correct mime type to datalink. </div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">In such case, the result of the above query will always be an empty set.</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><br class=""></div><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">2) a different way of reading 2.1.17 is that FORMAT determines which access_format will be used in output, that is...</p><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">if ...&FORMAT=application/fits</p><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">then the returned votable will contain:</p><div class="">access_format=application/fits</div><div class="">access_url=the URL to directly download the FITS file (and not a datalink)</div><p style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">while if FORMAT=application/x-votable+xml;content=datalink</p><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">then the access_format will be "application/x-votable+xml;content=datalink”</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">and the access_url will return the datalink link.</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><br class=""></div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><br class=""></div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">Could you please help me understand the 2.1.17 specification?</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><div style="font-variant-ligatures: normal;" class="">I would go for interpretation (2) above, but I see that some of you have implemented (1) instead...</div><div class=""><br class=""></div></div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">Many thanks in advance,</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class="">Alberto</div><div style="font-family: "Segoe UI", "Helvetica Neue", "Apple Color Emoji", "Segoe UI Emoji", Helvetica, Arial, sans-serif; font-size: 14px; font-variant-ligatures: normal; orphans: 2; widows: 2;" class=""><br class=""></div></body></html>