topic Extract lake surface in ArcGIS Spatial Analyst Questions https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684724#M10014 <HTML><HEAD></HEAD><BODY><P>Hello. Thank you in advance for any reply!</P><P></P><P>I use EVI to help extract water surface of a lake. The result is acceptable but not accurate. I don't want to include the extra small pixel plots when counting the total pixel number of the large lake. How can I erase the "noise" pixels? I've marked "noise" out in the second pic. BTW, this is a raster file and has been reclassified into two categories: 0 for Non-lake, 1 for lake (Blue)</P><P><IMG alt="Capture.PNG" class="image-1 jive-image" src="https://community.esri.com/legacyfs/online/179978_Capture.PNG" style="width: 620px; height: 472px;" /></P><P><IMG alt="Capture1.png" class="image-2 jive-image" src="https://community.esri.com/legacyfs/online/179979_Capture1.png" style="width: 620px; height: 472px;" /></P></BODY></HTML> Tue, 09 Feb 2016 20:08:58 GMT Zihan_Lin 2016-02-09T20:08:58Z Extract lake surface https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684724#M10014 <HTML><HEAD></HEAD><BODY><P>Hello. Thank you in advance for any reply!</P><P></P><P>I use EVI to help extract water surface of a lake. The result is acceptable but not accurate. I don't want to include the extra small pixel plots when counting the total pixel number of the large lake. How can I erase the "noise" pixels? I've marked "noise" out in the second pic. BTW, this is a raster file and has been reclassified into two categories: 0 for Non-lake, 1 for lake (Blue)</P><P><IMG alt="Capture.PNG" class="image-1 jive-image" src="https://community.esri.com/legacyfs/online/179978_Capture.PNG" style="width: 620px; height: 472px;" /></P><P><IMG alt="Capture1.png" class="image-2 jive-image" src="https://community.esri.com/legacyfs/online/179979_Capture1.png" style="width: 620px; height: 472px;" /></P></BODY></HTML> Tue, 09 Feb 2016 20:08:58 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684724#M10014 Zihan_Lin 2016-02-09T20:08:58Z Re: Extract lake surface https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684725#M10015 <HTML><HEAD></HEAD><BODY><P>See <A href="http://pro.arcgis.com/en/pro-app/tool-reference/spatial-analyst/generalization-of-classified-raster-imagery.htm">this help page</A>. Start at Identifying Clusters with Region Group. Basically, Region Group, Extract By Attributes (or Con), Nibble.</P></BODY></HTML> Tue, 09 Feb 2016 20:15:24 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684725#M10015 DarrenWiens2 2016-02-09T20:15:24Z Re: Extract lake surface https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684726#M10016 <HTML><HEAD></HEAD><BODY><P>Interesting ... I would agree with Darren, however, unless you have greatly oversimplified what you consider noise, there are some regions that have smaller clusters yet you haven't circled them.&nbsp; Would be fair to say, that you didn't circle all the noise?&nbsp; What about that big lump in the South East corner... is that noise too?</P><P></P><P>So follow Darren's suggestion, perhaps with a focal majority with a moderate sized neighbourhood first to get rid of speckle.&nbsp; Then do the RegionGroup incrementally until you get most of what you call noise identified</P></BODY></HTML> Tue, 09 Feb 2016 21:10:17 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/extract-lake-surface/m-p/684726#M10016 DanPatterson_Retired 2016-02-09T21:10:17Z