Friday, August 14, 2015

New tool - Landsat image pre-processing in ArcGIS - Part I

Landsat is powerful resource for measuring changes on the Earth's surface over the past > 30 years. However, ArcGIS users lack image pre-processing tools available in remote sensing packages, such as ENVI and ERDAS. Through the years I've trialed and error-ed with different image pre-processing workflows with varying success. Some workflows actually ended up making the data worse off than when I began! Recently I decided to post the Landsat Toolbox that I've developed to facilitate my own image processing - http://www.arcgis.com/home/item.html?id=a60b0120a79f45ae990bb85f4d12edee .


The Landsat Toolbox for ArcGIS provides many basic preprocessing tools that can be used to help facilitate change detection and vegetation dynamics studies. This toolbox lessens the need for commercial remote sensing packages, such as ENVI or ERDAS, and brings some image processing functionality directly into ArcMap. Image pre-processing involves steps that may be under-appreciated by some GIS analysts, but are nonetheless important for ensuring reliable outcomes. This toolbox contains tools to do the following:

1) Convert raw DN values to top-of-atmosphere reflectance
2) Perform radiometric normalization using user-selected pseudo-invariant pixels
3) Perform topographic corrections using a digital elevation model
4) Mosaic adjacent scenes using linear regression to ensure a smooth edge-match

Many of the tools in this toolbox require fmask or fmask for R to perform cloud, cloud shadow, and snow masking prior to running. However, you could also do the masking manually by setting any value that you wish to remove to > 0.








4 comments:

  1. Hi Tom,
    I tried to use this tool but received error message. I have created random points in Arcgis and mask file using another tool not the fmask. But I created the fmask pixel greater than 1. Any solution for this?? Thanks.

    ReplyDelete
  2. It is hard to know what it might be without the specific error message. If I knew the specific error message I might be able to take a guess.

    ReplyDelete
  3. I got "ERROR 000576: Script associated with this tool does not exist.".

    ReplyDelete
  4. Hi Alexis,

    The script is there, but sometimes ArcMap has a tough time when the drive letter is different on your computer vs. mine. In ArcCatalog right click on the model --> properties --> source --> then browse to the location of the script on your computer.

    ReplyDelete