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11 Aug

I recently migrated all the content from this blog to my new website!, I’m looking forward to see you there.

Hi all,

I hope you are having a great summer! Just a quick note to say that I’m migrating my blog to my new website. I hope you like it and continue following my research. Don’t hesitate to contact me anytime 🙂

How to extract the values from Time series data in Idrisi

15 Apr

Hello guys,

Time series data

With GIS you can explore a series of rasters depicting  the same geographical area through time, analyzing how an specific element or attribute changes. This is one of the purposes of Time series data. So, the other day I exchange a series of interesting emails with Idham Khalil from the Geography Department here at uni about how to extract and compare the values from a series of images.

If you have only few images, one way to compare two rasters is to subtract  one image from the other to see the changes through time, but of course it depends on the question you need to solve. On the other hand, if you have plenty images here is the solution to which Idham arrived using Idrisi Taiga:

Let say you are working with time series data and have hundreds of images(layers). And you want to find the behaviour of one pixel/polygon over times. One way of doing it is using earth Trend Modeler module in Idrisi Taiga. Load all the images in earth trend modeler and make them a raster group.Then go to Explore Temporal Profiles. This will generate a time series curve of certain pixel/region depending on your objective. Right click on the graph produced and …copy to clickboard as text(data only). Bingo….you will have the values of all those years.

As always, I deeply enjoy these conversations with other people so if you have something in mind that we can discuss regarding technical or theoretical issues behind GIS, please feel free to contact me 🙂

Happy modelling!

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