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Arhanghelul

Spatial analysis, regression and correlation between 2 rasters

16 posts in this topic

Hello !

I would like to make some spatial analysis regarding regressions and correlation coeficients between 2 rasters.

I have 2 rasters:

  1. Land use/ Land cover extracted from aerial images
  2. Land Surface Temperature (LST) derived from LANDSAT thermal band.

Both raster images are co-registered, in the same projection, having a RMSE error <=0.5 m.

Now I would like to see if there are some spatial correlations between these 2 images.

What software can I use for this task ?

I know that there are some specialised softwares like R and SPSS. But how to import and use rasters ?

Where can I find some tutorials, lab exercises or web-links about this ?

Thank you, my friends.

Arhanghelul

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did you check all toolbox of spatial analyst ...regards

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ENVI is the software for raster tasks as long as those two images have the same dimensions (row/line).

But it need some practice to handling it.

You can also check IDRISI a good tool

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here is the the code for spatial cross-correlation (Matlab)

there are 2 surfaces we are going to compare or find correlations

maybe you should convert them to raster first

A = imread ('...'/firstraster.jpg');

B = imread ('.../secondraster.jpg');

Result = normxcorr2(B,A);

size if B should be equal or lesser than size of A

the result is an arrey of correlation as kernel ( B moves across the Image A )

max(max(Result)) % the max xross corr found by kernel

imshow (Result) % xross surface

using ArcGIS can be very easy and helpful :)

ArcToolbox > Spatial Analyst > Multivariate > Band Collection Statistics ;)

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here is the the code for spatial cross-correlation (Matlab)

there are 2 surfaces we are going to compare or find correlations

maybe you should convert them to raster first

A = imread ('...'/firstraster.jpg');

B = imread ('.../secondraster.jpg');

Result = normxcorr2(B,A);

size if B should be equal or lesser than size of A

the result is an arrey of correlation as kernel ( B moves across the Image A )

max(max(Result)) % the max xross corr found by kernel

imshow (Result) % xross surface

using ArcGIS can be very easy and helpful :)

ArcToolbox > Spatial Analyst > Multivariate > Band Collection Statistics ;)

Thank you !

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Hi guys .. it might be late to answer this but I will explain the best way (as I can see)

first, u should use (extract by mask) which is one of the tool in ArcGIS where u can mask the first layer (i.e.LULC) using (LST) or vise versa

After finishing the masking, u can check in the properties that both layers have the same number of row and columns.

Second, use (raster to ASCII) tool which also available in ArcGIS to convert both layers into text format then open both of them using notepad or any other alternative program (I prefer Editpad Lite) and delete the header of them

Note: the header file can also show u the number of rows and columns of the resulted image.

Third, from file menu in SPSS, click on read text file and just click next until the part where u should define the number of columns where u should choose 1

do this process to the both layers then apply LR or any other algorithm u like to use.

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Hi guys .. it might be late to answer this but I will explain the best way (as I can see)

first, u should use (extract by mask) which is one of the tool in ArcGIS where u can mask the first layer (i.e.LULC) using (LST) or vise versa

After finishing the masking, u can check in the properties that both layers have the same number of row and columns.

Second, use (raster to ASCII) tool which also available in ArcGIS to convert both layers into text format then open both of them using notepad or any other alternative program (I prefer Editpad Lite) and delete the header of them

Note: the header file can also show u the number of rows and columns of the resulted image.

Third, from file menu in SPSS, click on read text file and just click next until the part where u should define the number of columns where u should choose 1

do this process to the both layers then apply LR or any other algorithm u like to use.

Thank you for your reply !

Where can I find some tutorials, lab exercises for using SPSS ? (about importing and creating new projects, how to create regressions and graphics ? )

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Regressions in SPSS is Normal. We can choose: Linear, Logistics, Curbic (Non - Linear) for simulating correlation between 2 raster.

step1: You make sample (than 30 sample) from Land use and Land Surface Temperature.

step2: You extract value of point from sample.

Step3: You use: SPSS or Statistic software (R software, statgraphics, spss....) to make correlation.

Step4: You use Gis software for compute raster (Multiply, split, add, subtract follow equation in step3).

Good luck!

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SPSS Statistics Essential Training

http://s6.p30download.com/users/606/tutorial/office/spss-statistics/Lynda.SPSS.Statistics.Essential.Training.Full_p30download.com.part1.rar
http://s6.p30download.com/users/606/tutorial/office/spss-statistics/Lynda.SPSS.Statistics.Essential.Training.Full_p30download.com.part2.rar

pass = www.p30download.com

disable your antivirus, there are nothing wrong with the files.

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Yes, the file is live. We can disable virus before downloading it!

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thanks for your guide. I have apply the same procedure but i have some problem with my ascii file. I exported my LST raster to ascii file but i contain -9999 values. i wonder if you could guide me to fix my file and second this does it matter if this file contain multiple rows and multiple columns please comment.

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Hola, un gusto saludarles, si tengo un mapa de temperatura y otro raster de NDVI, como puedo realizar el proceso de correlacion  y regresión usando software libre por ejemplo QGIS?

 

Gracias!

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