Python GDAL – How to Take Cell Size from Raster using Python, GDAL, or Rasterio

Question

How to take cell size per X,Y using simple python or GDAL or RASTERIO?
and hot to count how many pixels have my raster with some packages..

I have find some code but is pyqgis and I don't need this package :

ras  = QgsRasterLayer("C:/Users/myname/raster.tif")
pixelSizeX= ras.rasterUnitsPerPixelX()
pixelSizeY = ras.rasterUnitsPerPixelY()

print pixelSizeX
print pixelSizeY

Answer 1

With PyQGIS

ras  = QgsRasterLayer("raster.tif")
pixelSizeX= ras.rasterUnitsPerPixelX()
pixelSizeY = ras.rasterUnitsPerPixelY()
print pixelSizeX
2.11668210081
print pixelSizeY
2.11685012701

With GDAL

from osgeo import gdal
raster = gdal.Open('raster.tif')
gt =raster.GetGeoTransform()
print gt
(258012.37107330866, 2.11668210080698, 0.0, 163176.6385398821, 0.0, -2.1168501270110074)
pixelSizeX = gt[1]
pixelSizeY =-gt[5]
print pixelSizeX
2.11668210080698
print pixelSizeY
2.1168501270110074

With Rasterio

import rasterio
raster =  rasterio.open('raster.tif')
gt = raster.affine
print gt
Affine(2.11668210080698, 0.0, 258012.37107330866,
   0.0, -2.1168501270110074, 163176.6385398821)
pixelSizeX = gt[0]
pixelSizeY =-gt[4]
print pixelSizeX
2.11668210080698
print pixelSizeY
2.1168501270110074

Or (from sgillies)

pixelSizeX, pixelSizeY  = raster.res
print pixelSizeX
2.11668210081
print pixelSizeY
2.11685012701