topic NoData issues: Value of 256 MAP_DOWN for 8-bit raster in Data Management Questions https://community.esri.com/t5/data-management-questions/nodata-issues-value-of-256-map-down-for-8-bit/m-p/338229#M19235 <HTML><HEAD></HEAD><BODY><SPAN>Original User: sarajase</SPAN><BR /><BR /><SPAN>Hello All,</SPAN><BR /><BR /><SPAN>I have number of historic 8-bit single band (panchromatic) aerial photos in mostly TIFF, JP200 or MrSid formats. </SPAN><BR /><BR /><SPAN>These rasters have NoData value of 256. Do not know how it happens. </SPAN><BR /><BR /><SPAN>I am converting them into a different projection using python. I am using the environment setting&nbsp; "MAP_DOWN".</SPAN><BR /><BR /><SPAN>The assumption is that value 0f 256 becomes 255 and 255 would be NoData. That takes care of NoData value of 256 which was causing issues with serving the imagery. </SPAN><BR /><BR /><SPAN>The problem is that the resultant JP2000 (JP2) rasters are showing few holes in white areas (high values). Is this because of JPEG compression?</SPAN><BR /><BR /><BR /><SPAN>When I out put the rasters to TIFF images these pixels have the value of 254 (highest) and the rasters show no holes (NoData) in the middle of images.</SPAN><BR /><BR /><SPAN>Anymore insights? Is there a way to get the JP2s like the TIFFs?</SPAN><BR /><BR /><SPAN>Thanks to all ...</SPAN></BODY></HTML> Thu, 11 Jul 2013 16:36:02 GMT Anonymous User 2013-07-11T16:36:02Z NoData issues: Value of 256 MAP_DOWN for 8-bit raster https://community.esri.com/t5/data-management-questions/nodata-issues-value-of-256-map-down-for-8-bit/m-p/338229#M19235 <HTML><HEAD></HEAD><BODY><SPAN>Original User: sarajase</SPAN><BR /><BR /><SPAN>Hello All,</SPAN><BR /><BR /><SPAN>I have number of historic 8-bit single band (panchromatic) aerial photos in mostly TIFF, JP200 or MrSid formats. </SPAN><BR /><BR /><SPAN>These rasters have NoData value of 256. Do not know how it happens. </SPAN><BR /><BR /><SPAN>I am converting them into a different projection using python. I am using the environment setting&nbsp; "MAP_DOWN".</SPAN><BR /><BR /><SPAN>The assumption is that value 0f 256 becomes 255 and 255 would be NoData. That takes care of NoData value of 256 which was causing issues with serving the imagery. </SPAN><BR /><BR /><SPAN>The problem is that the resultant JP2000 (JP2) rasters are showing few holes in white areas (high values). Is this because of JPEG compression?</SPAN><BR /><BR /><BR /><SPAN>When I out put the rasters to TIFF images these pixels have the value of 254 (highest) and the rasters show no holes (NoData) in the middle of images.</SPAN><BR /><BR /><SPAN>Anymore insights? Is there a way to get the JP2s like the TIFFs?</SPAN><BR /><BR /><SPAN>Thanks to all ...</SPAN></BODY></HTML> Thu, 11 Jul 2013 16:36:02 GMT https://community.esri.com/t5/data-management-questions/nodata-issues-value-of-256-map-down-for-8-bit/m-p/338229#M19235 Anonymous User 2013-07-11T16:36:02Z