# Slant to Ground Conversion

## Ground Range To Slant Range Conversion

For ground projected products, the ground range to slant range (GRSR) conversion can be performed using the GRSR polynomial coefficients (GRSR_Coefficients) stored in the metadata. Once applied, the slant range location of a specific pixel in the ground range can be calculated from:

$R_{slant}(j)=\sum_{k=0}^{p+1} C_k ((j-1)\delta_r)^k,\qquad j=[1...n]$

Where:

• $$R_{slant}(j)$$ is the slant range for the $$j$$-th ground range pixel
• $$p$$ is the order of the ground range to slant range polynomial (grsr_poly_order in the metadata)
• $$C_k$$ is the $$k$$-th polynomial coefficient
• $$\delta_r$$ is the ground range spacing (range_spacing in the metadata)

## Ground Range To Incidence Angle Conversion

The nominal incidence angle is the angle between a given slant range and the WGS84 ellipsoid. This should not be confused with the local incidence angle, which is references to the local terrain. It can be calculated from the ground range using the Incidence_Angle_Coefficients in the metadata and:

$\theta(j)=\sum_{k=0}^{p+1} C_k ((j-1)\delta_r)^k,\qquad j=[1...n]$

Where:

• $$\theta(j)$$ is the incidence angle for the $$j$$-th ground range pixel
• $$p$$ is the order of the ground range to incidence angle polynomial (incidence_angle_poly_order in the metadata)
• $$C_k$$ is the $$k$$-th polynomial coefficient
• $$\delta_r$$ is the ground range spacing (range_spacing in the metadata)