topic Re: Calculate MSAVI2 in Raster Calculator in ArcGIS Spatial Analyst Questions https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81754#M1149 <HTML><HEAD></HEAD><BODY><P>Thanks; this also helps: Max value is now at 1.0</P><P>The minimum value, however, is still at 202.015.</P></BODY></HTML> Fri, 05 Aug 2016 14:39:41 GMT HarmenHuigens 2016-08-05T14:39:41Z Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81750#M1145 <HTML><HEAD></HEAD><BODY><P>I would like to calculate a Modified Soil-Adjusted Vegetation Index 2 on the basis of Landsat 8 OLI imagery, bands 5 (NIR) and 4 (RED), using the Raster Calculator. The formula should be:</P><P><A href="http://wiki.landscapetoolbox.org/lib/exe/fetch.php/remote_sensing_methods:msavi2_eq.png?cache=" title="View original file"><IMG alt="msavi2_eq.png" class="img_detail jive-image" height="114" src="http://wiki.landscapetoolbox.org/lib/exe/fetch.php/remote_sensing_methods:msavi2_eq.png?cache=&amp;w=900&amp;h=114&amp;tok=5f17b5" title="msavi2_eq.png" width="900" /></A></P><P>I have tried to convert this using the following map algebra expression in the Raster Calculator:</P><P>MSAVI2 = (2 * "NIR layer" + 1 - SquareRoot((2 * "NIR layer" + 1) ^ 2&nbsp; - 8 * ("NIR layer" - "RED layer"))) / 2</P><P></P><P>The returned values are between 0.5 and 58113.5. They should be between -1 and 1 though, so something is not right.</P><P>Any ideas about what is going wrong here?</P><P></P><P>Thanks!</P></BODY></HTML> Fri, 05 Aug 2016 13:43:47 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81750#M1145 HarmenHuigens 2016-08-05T13:43:47Z Re: Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81751#M1146 <HTML><HEAD></HEAD><BODY><P>^ is a boolean xor</P><P><A href="http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/raster-calculator.htm" title="http://desktop.arcgis.com/en/arcmap/latest/tools/spatial-analyst-toolbox/raster-calculator.htm">Raster Calculator—Help | ArcGIS for Desktop</A> </P><P>use pow or ** (I think)</P><P>is SquareRoot chosen from the list of operators or did you type it in</P></BODY></HTML> Fri, 05 Aug 2016 14:12:40 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81751#M1146 DanPatterson_Retired 2016-08-05T14:12:40Z Re: Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81752#M1147 <HTML><HEAD></HEAD><BODY><P><SPAN style="color: #3d3d3d; font-family: arial, helvetica, 'helvetica neue', verdana, sans-serif;">2 * "NIR layer" .....&nbsp;&nbsp;&nbsp; - 8 * ("NIR layer" - "RED layer"))) / 2</SPAN></P><P></P><P><SPAN style="color: #3d3d3d; font-family: arial, helvetica, 'helvetica neue', verdana, sans-serif;">make sure you make judicious use of floating point values</SPAN></P><P><SPAN style="color: #3d3d3d; font-family: arial, helvetica, 'helvetica neue', verdana, sans-serif;">2.0 * "NIR layer" ......- 8.0 * ("NIR layer" - "RED layer"))) / 2.0</SPAN></P></BODY></HTML> Fri, 05 Aug 2016 14:25:28 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81752#M1147 DanPatterson_Retired 2016-08-05T14:25:28Z Re: Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81753#M1148 <HTML><HEAD></HEAD><BODY><P>Thank you; ** is indeed the power operator.</P><P>SquareRoot is chosen from the operators list.</P><P></P><P>The result seems to be better although I still get values between -202.015 and 1.00195, with a mean of 0.12. The formula should give values only between -1 and 1.</P></BODY></HTML> Fri, 05 Aug 2016 14:30:09 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81753#M1148 HarmenHuigens 2016-08-05T14:30:09Z Re: Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81754#M1149 <HTML><HEAD></HEAD><BODY><P>Thanks; this also helps: Max value is now at 1.0</P><P>The minimum value, however, is still at 202.015.</P></BODY></HTML> Fri, 05 Aug 2016 14:39:41 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81754#M1149 HarmenHuigens 2016-08-05T14:39:41Z Re: Calculate MSAVI2 in Raster Calculator https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81755#M1150 <HTML><HEAD></HEAD><BODY><P>sorry... can you re-write the latest incarnation and check the reference formula...it wouldn't be the first time that I saw one of those wrong</P></BODY></HTML> Fri, 05 Aug 2016 17:56:39 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/calculate-msavi2-in-raster-calculator/m-p/81755#M1150 DanPatterson_Retired 2016-08-05T17:56:39Z