Pixel extraction tool

snap
1

Hi,

I am doing some validation of MERIS data using the SNAP pixel extraction tool, but I am having trouble with the time constraint. I would like to extract the pixel info for the same day of the in situ data. How can I do that?

If I select 1 day as time difference constraint, I also get info with plus/minus 1 day and not exactly the same day. I also tried using 20 hours as time constraint, but again it doesn’t work.

Thank you,
Mariana

2

You cannot explicitly request for data of the same day. What would come closest is to set a time difference of 12 hours, so you would span a 24 hour time period.

3

hello good evening i am working in S2 image and i need to extract pixel value of particular GCP point since i have no idea of this step in snap so kindly let me know friends

Thank You

4

Use pins to export pixel values, Source of the post

5

Thank you very much

6

I just load the .img file in qgis and extract the values to a shapefile by using raster>Zonal Statistics tool? But when the same image was co-registered with other images and converted to .tif, the above mentioned technique gave different values. I was working with RADARSAT-2 images. What might be the reason? Which is the right method to extract mean back scatter values for shapefiles?

7

probably because the image was resampled during the coregistration?