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<p>A <b>Helical Hyperspatial Code</b>, also known as an <b>HHCode</b>, is a data storage format for very large spatio-temporal datasets.
</p><p>The development of HHCode can be traced to efforts in the 1990's by Edric Keighan, Panagiotis A. Vretanos, Michael Galluchon, and Herman P. Varma while working for the <a href="Canadian_Hydrographic_Service" title="Canadian Hydrographic Service">Canadian Hydrographic Service</a>'s Atlantic regional offices at the <a href="Bedford_Institute_of_Oceanography" title="Bedford Institute of Oceanography">Bedford Institute of Oceanography</a> in <a href="Dartmouth%2C_Nova_Scotia" title="Dartmouth, Nova Scotia">Dartmouth</a>, <a href="Nova_Scotia" title="Nova Scotia">Nova Scotia</a>. CHS was facing a problem with storing very large spatial datasets acquired during <a href="Hydrographic_survey" title="Hydrographic survey">hydrographic surveys</a> (thus having a temporal element) and was seeking a method to store the datasets in a <a href="Relational_database" title="Relational database">relational database</a> structure.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>CHS scientists reportedly conceptualized a spatio-temporal indexing system during a hydrographic survey onboard <a href="CCGS_Hudson" title="CCGS Hudson">CCGS <i>Hudson</i></a> on <a href="Georges_Bank" title="Georges Bank">Georges Bank</a> during the summer of 1989. The indexing system involved an adaptation of a <a href="Riemann" class="mw-redirect" title="Riemann">Riemannian</a> <a href="Hypercube" title="Hypercube">hypercube</a> data structure, invoking a helical spiral through 3-dimensional space, which allowed for n-size of features.
</p><p>The actual implementation of the proposed indexing system was termed a <b>helical hyperspatial code</b> and it was first used by modifying an installation of the <a href="Oracle_database" class="mw-redirect" title="Oracle database">Oracle database</a> version 4. The HHCode indexing system permitted a highly efficient compression of not only spatial data but other data types as well, while improving search and retrieval times. The HHCode comprises a form of space filling curve and the concept was published by the CHS scientists in the <i><a href="International_Hydrographic_Review" class="mw-redirect" title="International Hydrographic Review">International Hydrographic Review</a></i>.
</p><p><a href="Oracle_Corporation" title="Oracle Corporation">Oracle Corporation</a> subsequently learned of the innovation which led to an agreement with the Government of Canada which saw the CHS scientists working with a team of Oracle programmers at an office in <a href="Hull%2C_Quebec" title="Hull, Quebec">Hull, Quebec</a> during the early 1990s to redevelop the Oracle database <a href="Kernel_(operating_system)" title="Kernel (operating system)">kernel</a>. The resulting software was the Oracle database version 7, with the Spatial Data Option (SDO). Subsequent development of the SDO has resulted in the <a href="Oracle_Spatial" class="mw-redirect" title="Oracle Spatial">Oracle Spatial</a> extension to current Oracle databases.
</p><p>With the HHCode being an open-source data format, several spatial data and software companies have adopted it in various products targeted at very large corporate data users, namely Helical Systems Inc. and CubeWerx.
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<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://patents.justia.com/patent/6161105">US Patent 6161105</a>, <a href="Oracle_Corporation" title="Oracle Corporation">Oracle Corporation</a>, December 2000.</span>
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<ul><li>Varma, H. et al. <i>A Data Structure for Spatio-Temporal Databases</i> (1990). International Hydrographic Review, Monaco, LXVII(1), January.</li></ul></div><!--htdig_noindex--><div><div class="zim-footer">
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