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Is there a method to know the exact pixel size (the original size) of a raster “aerial photo”?

I have purchased an Arial photo with 10 cm pixel size resolution, and I received a sample of it, but the issue here that I feel that the resolution on the image is not 10 cm , I come up with this conclusion by comparing these samples with other 10cm samples from other projects and the old aerial photos visually more clear than the new sample.

Both Erdas and ArcMAP shows the same pixel size (10cm) for both samples, and As I know you can produce any GSD in erads form the same Aerial photo by resampling the image to smaller pixels, and here the resolution stays the same but the pixels are smaller,

What I am trying to prove that this aerial photo was resampled form a higher GSD (maybe 15cm) to 10cm, is that possible?

  • The best approach will be to just produce snapshots of both your old and new side by side and send to vendor that you purchased the imagery and ask for a clarification. – fatih_dur Dec 18 '16 at 1:47
  • Thanks fatih, I have done this, but the vendor still claims that its 10cm and the difference in resolution is due to weather. I am searching for something that proves that its more than 10 cm in a technical method. – Ahmad saleh Dec 18 '16 at 15:46
  • I believe that you should find samples of such small and distinct objects which loose details at larger pixel size. Cars could be suitable or zig-zag and other paintings on the streets. I believe that haze makes objects soft and blurry while bigger pixel size makes them loose the details totally. You can generate test data by resampling some good images 10 cm -> 20 cm -> 10 cm. – user30184 Dec 19 '16 at 7:49
  • thanks for the advice I will try to generate different samples with different pixel sizes and compare them. – Ahmad saleh Jan 15 '17 at 19:12
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Upsample the image to the suspected resolution and Downsample it to the original. If the resulting and original are the same (or close enough), it is very likely that you have a lower resolution image.

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In addition to the response, I wanted to provide a tool that can be used to achieve this seeing that you are using ArcMap.

Resample-Data Management Toolset

Change the spatial resolution of your raster dataset and set rules for aggregating or interpolating values across the new pixel sizes

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