# 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)