New to Erdas but I have to do a project and I have chosen to do a landcover land change detection. I have two Landsat 5 images, five years apart from each other.

What is my next step?

I imagine I need to do all the preprocessing and after that, I am thinking of using raw image difference and NDVI.

I have Atcor, will that be what I need to convert my DNS into reflectance?

  • 2
    Welcome to GIS:SE jkamsu! It is generally encouraged to only ask one question at a time so I've edited your post. But feel free to re-edit or roll-back any changes if I didn't make it clearer.
    – Joseph
    Apr 28 '15 at 9:21
  • Update: I actually found the landsat scenes that are already corrected and in surface reflectance, do I now need to perform geometric corrections or have those already been added to the data as well?
    – jkamsu
    Apr 28 '15 at 21:20
  • Details on processing levels: landsat.usgs.gov/Landsat_Processing_Details.php
    – Aaron
    Apr 28 '15 at 23:29
  • Before starting to get into the analysis, I would recommend checking if all the image are of same/ similar month, zenith angle and file format. This will minimize any chance of seasonal variability, shadow diversity and file corruption. ERDAS kind of like the *.img format. To find about your data check the metadata (MTL file) that came with it. This article describes how to read a meta file.
    – blu_sr
    Oct 12 '16 at 14:50

ATCOR for Erdas Imagine will convert DN to true reflectance--this step is critical for change detection analyses. Then you can use DeltaCue add-on in Erdas Imagine to detect land cover change. More details on the DeltaCue add-on can be found here. Additionally, there is a fairly good instructional video on how to use DeltaCue to get you started.

I would also recommend reading the literature on change detection--all of the papers describe in detail the preprocessing and change detection methods in detail. Here are a few to get you started:

Song, C., Woodcock, C. E., Seto, K. C., Lenney, M. P., & Macomber, S. A. (2001). Classification and change detection using Landsat TM data: when and how to correct atmospheric effects?. Remote sensing of Environment, 75(2), 230-244.

Howarth, P. J., & Wickware, G. M. (1981). Procedures for change detection using Landsat digital data. International Journal of Remote Sensing, 2(3), 277-291.

Chetverikov, B., Babiy, L., & Dorozhynskyy, O. (2013). Determining the influence of the earthquake on the change (s) of objects using remote sensing data. Geomatics, Landmanagement and Landscape.

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