<div dir="ltr">Hi,<div>I'm looking at a geotiff file that has the following band information:</div><div><br></div><div><div><div>Band 1 Block=256x8 Type=Byte, ColorInterp=Red</div><div> Mask Flags: PER_DATASET ALPHA </div><div>Band 2 Block=256x8 Type=Byte, ColorInterp=Green</div><div> Mask Flags: PER_DATASET ALPHA </div><div>Band 3 Block=256x8 Type=Byte, ColorInterp=Blue</div><div> Mask Flags: PER_DATASET ALPHA </div><div>Band 4 Block=256x8 Type=Byte, ColorInterp=Alpha</div></div><div><br></div><div>I'm not sure what a "mask with per dataset alpha" means.... if I had to venture a guess,</div><div>it looks like each band has its own private extra information as a sidecar 8 bit band.</div><div>(but if it's the case, why have a alpha band, with its own per dataset alpha?).<br></div><div><br></div><div>tiffinfo also just reports 4 samples per pixel:</div><div><br></div><div><div>> tiffinfo /tmp/gwc_test.tiff </div><div>TIFFReadDirectory: Warning, Unknown field with tag 33550 (0x830e) encountered.</div><div>TIFFReadDirectory: Warning, Unknown field with tag 33922 (0x8482) encountered.</div><div>TIFFReadDirectory: Warning, Unknown field with tag 34735 (0x87af) encountered.</div><div>TIFFReadDirectory: Warning, Unknown field with tag 34737 (0x87b1) encountered.</div><div>TIFF Directory at offset 0x8 (8)</div><div> Image Width: 2048 Image Length: 1096</div><div> Bits/Sample: 8</div><div> Sample Format: unsigned integer</div><div> Compression Scheme: LZW</div><div> Photometric Interpretation: RGB color</div><div> Extra Samples: 1<unassoc-alpha></div><div> Samples/Pixel: 4</div><div> Rows/Strip: 1</div><div> Planar Configuration: single image plane</div><div> Tag 33550: 0.008343,0.008343,0.000000</div><div> Tag 33922: 0.000000,0.000000,0.000000,492999.995534,5878229.148718,0.000000</div><div> Tag 34735: 1,1,0,7,1024,0,1,1,1025,0,1,1,1026,34737,22,0,2049,34737,7,22,2054,0,1,9102,3072,0,1,32632,3076,0,1,9001</div><div> Tag 34737: WGS 84 / UTM zone 32N|WGS 84|</div><div> Predictor: none 1 (0x1)</div></div><div><br></div><div>Also wondering, if this "per dataset alpha" a GDAL specific extension, or is it part of the TIFF standard?<br></div><div>Looking at the spec it might be related to the ExtraSamples tag, but I'm understanding how</div><div>it related with the above band interpretation.</div><div><br></div><div>Cheers</div><div>Andrea</div><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><div><div>==</div><div>GeoServer Professional Services from the experts! Visit</div><div><a href="http://goo.gl/it488V" target="_blank">http://goo.gl/it488V</a> for more information.</div><div><span style="font-size:12.8px">==</span><br></div></div><div><br></div></div><div>Ing. Andrea Aime <br></div><div>@geowolf</div><div>Technical Lead</div><div><br></div><div>GeoSolutions S.A.S.</div><div>Via Poggio alle Viti 1187</div><div>55054 Massarosa (LU)</div><div>Italy</div><div>phone: +39 0584 962313</div><div>fax: +39 0584 1660272</div><div>mob: +39 339 8844549</div><div><br></div><div><a href="http://www.geo-solutions.it" target="_blank">http://www.geo-solutions.it</a></div><div><a href="http://twitter.com/geosolutions_it" target="_blank">http://twitter.com/geosolutions_it</a></div><div><br></div><div><p><span lang="IT"><font size="1"><b>AVVERTENZE AI SENSI DEL D.Lgs. 196/2003</b></font></span></p><p><span lang="IT"><font size="1">Le informazioni contenute in questo messaggio di posta elettronica e/o nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il loro utilizzo è consentito esclusivamente al destinatario del messaggio, per le finalità indicate nel messaggio stesso. Qualora riceviate questo messaggio senza esserne il destinatario, Vi preghiamo cortesemente di darcene notizia via e-mail e di procedere alla distruzione del messaggio stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso, divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od utilizzarlo per finalità diverse, costituisce comportamento contrario ai principi dettati dal D.Lgs. 196/2003.</font></span></p><p><span lang="IT"><font size="1"> </font></span></p><p><font size="1">The information in this message and/or attachments, is intended solely for the attention and use of the named addressee(s) and may be confidential or proprietary in nature or covered by the provisions of privacy act (Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection Code).Any use not in accord with its purpose, any disclosure, reproduction, copying, distribution, or either dissemination, either whole or partial, is strictly forbidden except previous formal approval of the named addressee(s). If you are not the intended recipient, please contact immediately the sender by telephone, fax or e-mail and delete the information in this message that has been received in error. The sender does not give any warranty or accept liability as the content, accuracy or completeness of sent messages and accepts no responsibility for changes made after they were sent or for other risks which arise as a result of e-mail transmission, viruses, etc.</font></p></div><div><br></div><div>-------------------------------------------------------</div></div></div></div></div></div></div></div></div></div></div></div></div>
</div></div>