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I would like to come up with the spatial variation of NDVI of a certain area. I have the average NDVI from 1998 to 2014. I'm using Arcgis 9.3

  • What do you mean by "average NDVI from 1998 to 2014". Is it means you have 17 (98-14) NDVI layers or One layer any way – SIslam Jan 10 '15 at 7:55
  • I have 17 ndvi layers from year 1998 to 2014 – favour Jan 10 '15 at 8:30
  • @ msi_g Yes, I have 17 ndvi layers from year 1998 to 2014 – favour Jan 10 '15 at 8:36
  • Are these layers in Raster or Vector format? – SIslam Jan 10 '15 at 8:42
  • If vector then follow one way and if not then another..Please confirm Raster or Vector – SIslam Jan 10 '15 at 8:46
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These 17 NDVI layers contains values range from -1 to 1. If you want to see the spatial variation i.e. where is the high/low vegetation then you need spatial analyst extension. Workflow for high vegetation is as below.

1.Load all 17 layers in the arc map and Cell Statistics Tool
2.Go to Toolbox>Spatial Analyst>Local>Cell Statistics
3.Set overlay statistic as MAXIMUM (as we need high vegetation so we need to extract higher values from NDVI layer)
4.Run the tool

I am attaching example for two layers as below Cell Stat

Same if you want low vegetation. Just set Minimum.

N.B.It does not give story by year/yearwise rather gives where was/is the high/low vegetation in the span of 17+ years There are many ways that depend on what you want. I used ArcGIS 10.1 but it is same in case of 9.3

  • @ msi_g, I would like the ndvi to be shown as a range e.g 0.1-0.2, 0.2-0.3, 0.3-0.4, – favour Jan 10 '15 at 13:40
  • @favour Could u explain what u really want- To show the present vegetation intensity(high/low area) or change of vegetation intensity over time(17 years). – SIslam Jan 10 '15 at 13:46
  • I would like to have a spatial variation of change of vegetation intensity within a specific area overtime (17 years) – favour Jan 10 '15 at 14:11
  • Then you have the map any way, because you can not combine these 17 maps into one map caring your demand above. Just apply the class and generate map.Then you have 17 maps.. – SIslam Jan 10 '15 at 15:35

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