<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Dec 20, 2024, at 4:56 PM, Even Rouault via gdal-dev <gdal-dev@lists.osgeo.org> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;">Besides reprocessing all of our existing grids,</span><a class="moz-txt-link-freetext" href="https://github.com/geotiffjs/geotiff.js/tree/master/src/compression" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">https://github.com/geotiffjs/geotiff.js/tree/master/src/compression</a><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;"><span class="Apple-converted-space"> </span>seems to show that it doesn't support ZSTD, which would break at least our wonderful<span class="Apple-converted-space"> </span></span><a href="http://cdn.proj.org/" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">cdn.proj.org</a><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;">interactive map</span></div></blockquote></div><br><div>To throw a wrench into it... </div><div><br></div><div>geotiff.js has LERC support. Floating point LERC TIFFs compressed with a MAX_Z_ERROR to one decimal better than the *stated precision* of the grids would be smaller and more efficiently compressed/decompressed. By maybe a 1/3rd over zstd and deflate.</div><div><br></div><div>See this great write-up by LINZ about the topic https://github.com/linz/elevation/tree/master/docs/tiff-compression </div><div><br></div><div>Howard</div></body></html>