Satellite image displacement?

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Hi!

I'm extracting at least 2-3 images daily of satellite imagery in order to track clouds. I've noticed that the basemap and the satellite image does not register (overlap completely). Does anyone know why? I was trying to put some other information on top of the satellite image and playing around with transparency when I came across with this problem. I've attached some image, hope it helps to show this issue You could see it if you zoom nearby pacific shoreline, which is quite visible in the sat_vis imagery.

Thanks in advanced

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Juliomm

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Posted 6 years ago

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Brendan Hayes, Official Rep

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Try playing with the proj variable listed here: http://www.wunderground.com/weather/a...

You might be viewing the map in Mercator when you don't mean to be
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Juliomm

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Hi Brendan!

Thanks for your rapid answering!

I've already tried with both but I have the same result. I 'burned' a vector layer on the images and I get the same displacement. I'm using GDAL library by the way to do this. I'm not sure if I need to load the images again; if you want, I can upload them again.

My call is:
"http://api.wunderground.com/api/MY_KE..."

Just changed ll for me at the end.
The strange thing is that the basemap is on its right place! But both images ('ll' and 'me') are identical.

Regards!
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Juliomm

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Hi!

Here's another example. I used this query:

http://api.wunderground.com/api/MY_KE....

I attached a snapshot of the resultant image. As you can see, on Yucat√°n Peninsula, Golf of Mexico, costline of basemap is shifted south from satellite image. Shift seems not to be constant along the map, maybe due to rounding errors on geographic coords (pixel size on the ground).

Regards!
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Juliomm

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HI!

Any comment on this? I think it's important, cause if the image and basemap are not completely overlaid, any map published with satellite imagery on top is inaccurate at least.

Best regards!
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Juliomm

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Hi!

JFYI, It was my bad ... I had a problem on georeferencing, on calculating pixel size in decimal degrees.

Thanks anyway!!!

Best regards