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I'm using Landsat L1G for our project and need L1G to be geometric corrected for later use. One thing I know for sure that L1G need to be employed a Digital Elevation Model (DEM) for topographic accuracy. I follow a guide to use ArcMap (from ArcGIS) to correct the uncorrected Landsat image. But the process required DEM and DOQ (Digital orthophoto quadrangle) image to run. DEM is available but DOQ is not available outside US.

As I read, ArcMap using DOQ to establish the GCPs for uncorrected image. Since the DOQ is not available, I wondering if only using DEM to correct the L1G image is good enough? In other hands, can anyone know that the Landsat L1G is corrected with GCPs?

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We decided to use data from L1T source instead. But I face another problem can't find any information about satellite observation zenith angle/azimuth of Landsat image. We need it to make sure two different image has the same condition for further calculation. Any one have idea where I can find that information?

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L1G products are geometrically corrected, but without terrain information (so this is not the most precise type of correction, but OK in relatively flat areas or near the center of the image).

You should be aware that it is not possible to apply rigourous orthorectification methods based on already geometrically corrected images. I would therefore suggest you to use L1T data. Maybe the data from M. Hansen et al could also help you (it is a global cloud free mosaic in 3-4-5-7 for 2000 and for 2012).

Finally, you can get GCP's from many data sources in order to improve your georeferencing. In ArcGIS there is an online image layer that can be added to find such GCP's. Or you can use Google Earth, etc..

  • @radouxjiu: thanks very much. The main reason I want to use L1G is because L1T is sometime not avaiable for my interested region. Our goal is to derive the AOD change from Landsat image (using Sifakis mapping method) so Im not sure the dataset from Hansen is useful or not but I'll have a look at those data. Thanks again :) "it is not possible to apply rigourous orthorectification methods based on already geometrically corrected images" you mean I cann't employ DEM for orthorectification of L1G to get the L1T data? since there are a lot of paper about this kind of correction. – Hung Luu Mar 19 '14 at 15:51
  • what I mean is that, from what I know, L1T data are not produced based on L1G data. There are some method that could be quite precise, but in theory not as good as the L1T from raw data. The data from Matt Hansen could help you if you use a method like AROD. – radouxju Mar 19 '14 at 16:37
  • @HungLuu I'd suggest changing from Arc-anything to R or Grass. If you are comfortable with R, see of landasat package. topocorr is what you're looking for – Paulo Cardoso Mar 20 '14 at 11:23
  • thanks all for your help. we decided to use data from L1T source instead. But I face another problem cant find any information about sattelite observation zenith angle/azimuth of Landsat image. We need it to make sure two different image has the same condition for further calculation. Any one have idea where I can find that information? – Hung Luu Mar 27 '14 at 3:35

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