Projecting from UTM results in stairstep pattern

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03-06-2012 08:49 AM
by Anonymous User
Not applicable
Original User: rs60

I have a high resolution RapidEye image that was delivered in UTM 10, WGS84.  When I reproject this image, the resulting output has a systematic stairstep pattern in it that seems too uniform.  Every 31 to 32 pixels in both the north/south and east/west direction, there is a shift of 1-2 pixels.   It really stands out in the roads and other linear features found throughout the image.  I am getting the same result when I reproject any UTM image to another projection and/or datum, although the length of the stairsteps varies depending on the output projection.  But if my input imagery is in a different projection, say Geographic, I am not seeing this systematic shift in the output;  the linear features have a more normal, irregular nearest-neighbor blockiness. 

I've attached a .jpg of an output image.  Again, the absolute uniformity of the stairsteps throughout the output image is what raises questions with me.

Is this just a function of reprojecting from UTM and is "normal"?  Or is there a problem with the transformation? 

I would really appreciate any insight that could be provided. 

Thanks,
rs
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1 Reply
by Anonymous User
Not applicable
Original User: dasmy004

Hi rs,

check the re sampling method.
it is most likely that you are using nearest neighbor.
try using Bilinear or cubic convolotion

Regards,
Mohammad
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