Extract spatial data using shp file as a mask

I'm new in matlab
So I tried to extract pixel data from a modis bands image with point as a central for 5x5 box.
So the 5x5 box will be filled with modis image's pixel.
I already did it in qgis, but it failed.
The yellow dot contains lattitude, longitude and target data.
Is there any refrence to do this? I already read some examples, but they are only using the box (shp file) to fill it.
For future works, I want to generate 4D data [n,x,y,t]
n = for band's modis image
x,y = box
t = data target

6 commentaires

yanqi liu
yanqi liu le 19 Déc 2021
yes,sir,which is the image process target? get the yellow point location?
What is qgis, and did you do it there? Or did it fail there?
What/where exactly is "the box"? Is it the rectangular region where the 4 yellow dots define the corners?
I'm not sure what n is. Is this image not gray scale but maybe multispectral with several wavelength bands?
I don't know what t (the "data target") is. Is it the gray level?
I don't know what the 4-D data would be. So, let's say n=1, x=2, y=55, and t = 163. What would the value at your output array output(1, 2, 55, 163) represent? What goes into that location of the 4-D array?
Fadhurrahman
Fadhurrahman le 20 Déc 2021
Modifié(e) : Fadhurrahman le 20 Déc 2021
  1. so modis has 7 bands. so the 'n' will be filled n=1,2,3...7.
i want to extract pixel data on image with 5x5 box with yellow dot as a refrence. so x,y will be filled x=5 y=5
the 't' data comes from yellow dot, let's just say t=163.
so the output array will be (1,5,5,163), with 5x5 has a pixel data in it.
2. this image is a wavelenght bands.
3. "the box" in this image is just an illustration for 5x5 box that i want to do it in matlab.
4. qgis is a software for geospatial analysis. just like arcgis but its a free version. i already tried in qgis but it fails
Fadhurrahman
Fadhurrahman le 20 Déc 2021
thank you so much @Walter Roberson i'll be sure to try it out
Fadhurrahman
Fadhurrahman le 23 Déc 2021
@yanqi liu so the yellow dot is the point where i want to put 3x3 box to extract pixel modis data

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R2020a

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le 23 Déc 2021

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