Canopy density & NDVI Regression using ArcGIS for Desktop?

Question

I have a Landsat ETM+ image, I also have 200 sample points with coordinates,canopy density, different band values and NDVI values.

If I build OLS model I only got sample points regressed.

How can I join the image and the points so I can do regression and produce a map in ArcGIS for Desktop?

PolyGeo · Accepted Answer · 2016-08-26 05:29:21Z

1

In ArcGIS I'll give you a blueprint to follow.

Convert your sample points into a shapefile.
Project / Reproject your shapefile to match your ETM+ image, mostly likely UTM but not always.
Use the Sample or Extract multi-value to points tool to bring the values from the ETM+ image to your shapefile.
Run the OLS in ArcGIS.
Render the shapefile with the OLS values. Usually some form of residual map.

PolyGeo♦

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answered Sep 22, 2014 at 22:08

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Thanks for answering!This is how I did yesterday:1),exported all sample points by first ‘Display XY data’ and then ‘Export data’; 2),use "Sample" extracted all points from ETM+ image, then I got a table and exported it to a DBF file. 2), I copied all band values from DBF to original sample .xls file, calculated NDVI; 3), I also did linear regression in .xls, since I'm asked to apply the equation to the EMT+ image for mapping, I joined the .xls (with NDVI) to sample points shape file; 4), ran OLS, failed.
– ZhangYao Jiayin
Commented Sep 23, 2014 at 6:11
Between steps 3 & 4. Do not run 0LS on the joined data. Export to a new shapefile and run OLS on this new file.
– If you do not know- just GIS
Commented Sep 23, 2014 at 12:34
still not working efter join→export....only got sample points regressed...
– ZhangYao Jiayin
Commented Sep 23, 2014 at 15:21
Got a PDF from my teacher, we have to use Image Analysis in ArcGIS to calculate NDVI for ETM+ image, then applying NDVI raster layer in regression equation in Map Algebra. I can produce the map now except it seems I got different Band values after 'Sample': I got NP_2_30513,14...17, I assumed they are band3,band4...band7 and used them calculated NDVI in Excel. Did I interpolate them wrong? Is that why my regression is different from my techer's?
– ZhangYao Jiayin
Commented Sep 23, 2014 at 17:16

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