Wednesday, October 23, 2013

Module 7 Multispectial Analysis

For this module in Remote Sensing we were to identify certain features of an image based on their pixel count in certain layers.  This was accomplished using the image histogram and the inquire cursor tool.
In layer four there was a spike between pixel values 12 and 18. This was on the left side of the histogram, and from the module I knew this would mean a dark area of the image.  From the image it appeared this may be deep water. Using the search cursor I verified that there was a correlation between pixels in the histogram and the area I had selected on the image.  Once this was done I used the Inquire box and the Subset & Chip tool to select an area that best depicted this feature in the image and saved this as new file. I then opened the file in ArcMap and created the map above.
In layers 1-4 there was a small spike around pixel value 200 and a large spike between pixel values 9 and 11 in layers 5 and 6. This was on the right side of the histogram, and from the module I knew this would mean a very light area of the image.  From the image it appeared this may be the snowcapped mountains. Using the search cursor I verified that there was a correlation between pixels in the histogram and the area I had selected on the image.  Once this was done I used the Inquire box and the Subset & Chip tool to select an area that best depicted this feature in the image and saved this as  a new file.  I then opened the file in ArcMap and created the map above.
  
 
 
 
In certain areas of the water, layers 1-3 are much lighter than normal.  Layer 4 was a little brighter and layers 5 and 6 were unchanged. From the image it appeared this may be several areas of shallow water. Using the search cursor I verified that there was a correlation between pixels in the histogram and the area I had selected on the image.  Once this was done I used the Inquire box and the Subset & Chip tool to select an area that best depicted this feature in the image and saved this as a new file. I then opened the file in ArcMap and created the map above.
 
 

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