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Orthorectification and Georeferencing

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07-22-2015 12:39 PM
deleted-user-G61IFj8--dM5
by
New Contributor
‎07-22-2015 12:39 PM

I would like to perform a change detection on two GeoEye images acquired a year apart. The images I received from DG are standard products and have not been orthorectified or georeferenced. DG has provided an .rpb file with each of the image files, but the only way I seem to be able to "use" them with the orthorectification tool in Image Analysis, is when I load the .til image file into my map document. 

Question 1: can someone explain to me the difference between the .til and the .tif files? If orthorectification can only be performed on the .til file, is that the file I need to be working with in my analysis?

In addition, I would like to georeference the two images so they are lying exactly one on top of the other. The area of interest is the same.

Question 2: Can I simply georeference the two images to one another vs. georeferencing them using a known/verified data set like an existing map or imagery basemap?

Thanks for any insight and help!

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1 Reply
larryzhang
by
Occasional Contributor III
‎07-22-2015 11:10 PM

A.,

GeoEye-1 products are usually referred to three catalogues:

  1. Geo
  2. GeoPro
  3. GeoStereo

If correct, your so-called standard GeoEye product should be the type: Geo, which should have .RPC and standard .TIF (with .TFW) in the folder from DG.

However, from your description above, the .RPB and .TIL in the folders are available. If so,  your data should be WorldView-2 or WorldView-3, rather than GeoEye-1.

Please contact the data provider for confirmation.

++++++++++

Once confirmed (no matter which sensor, WV-2, WV-3 or GEOEYO-1), you can follow the instructions to solve your abovementioned two issues:

With ArcGIS, advisable to use Mosaic Dataset model in ArcGIS 10.1 or later. If new to you, please follow the tutorials at What is a mosaic dataset?—Help | ArcGIS for Desktop  to load, enhance color, etc.

If two mosaic datasets (holding two different years' GeoEye images) are not aligned very well each other, you can use the bundle adjustment in 10.3 at http://desktop.arcgis.com/en/desktop/latest/manage-data/raster-and-images/block-adjustment-for-mosai...