Object Based Image Analysis SAGA GIS

An Object Based Image Analysis (OBIA) approach to image classification segments an image into homogenous spectral regions. Image segmentation is the process of grouping multiple adjacent pixels into polygon ‘Objects’ based on similar spectral characteristics. This differs from standard image analysis methods that classify each pixel in isolation; the OBIA approach generally produces a cleaner map product, more meaningful to human users.

Using the new ‘chain tools’ function in SAGA, that allows multiple  modules to be linked into one process, the developers have created a new Object Based Image Analysis module that works beautifully.

Below is an example of using this function for classify a mine area in Sulawesi, Indonesia.

Another example – mapping fires in Northern Australia. – Updated April 2015

 

This example uses SAGA-GIS 2.2.5 to conduct a supervised OBIA segmentation based classification.

The example below shows how to map one fire  event by subtracting an image after a fire from one before. The example is of a fire that escape from a mine tenure into Kakadu national park.

NOTE: I have noticed on one install the Tool Chain modules missing including the OBIA classification. This can be easily fixed by going to saga_2.2.0_x64\modules\toolchains and dragging and dropping the tool chain modules into SAGA.

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7 thoughts on “Object Based Image Analysis SAGA GIS

    1. cycadmedia Post author

      Hi Rajit, I am sure it could be used to count trees if you have the right imagery. I think there are ways you can classify each segment based on shape parameters but I have not played with this. Good luck!

      Reply
  1. Even

    Hi, I can no longer see the Object Based Image Classification in the Imagery Menu. Has SAGA removed this? Thanks!

    Reply
  2. Even

    Hi! Did SAGA GIS removed the object based classification? I can no longer see the module in the most recent version. Thanks!

    Reply
    1. cycadmedia Post author

      I have noticed on one install the Tool Chain modules missing including the OBIA classification. This can be easily fixed by going to saga_2.2.0_x64\modules\toolchains and dragging and dropping the tool chain modules into SAGA.

      Reply

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