We need the ability to write rotated and skewed geotransforms in HFA (.img / .aux) files. This means writing it to look like:
MapInformation(Eimg_MapInformation) @ 913 + 45 @ 1041
+ projection =
+ string = `NAD_1927_UTM_Zone_11N'
+ units =
+ string = `meters'
MapToPixelXForm(Exfr_GenericXFormHeader) @ 498 + 23 @ 626
+ titleList =
+ string = `Affine'
XForm0(Efga_Polynomial) @ 649 + 136 @ 777
+ order = 1
+ numdimtransform = 2
+ numdimpolynomial = 2
+ termcount = 3
+ exponentlist[0] = 0
+ exponentlist[1] = 0
+ exponentlist[2] = 1
+ exponentlist[3] = 0
+ exponentlist[4] = 0
+ exponentlist[5] = 1
+ polycoefmtx[0] = 0.0431012353078778
+ polycoefmtx[1] = 0.00122005255541221
+ polycoefmtx[2] = 0.00284370628720125
+ polycoefmtx[3] = -0.0422836422712025
+ polycoefvector[0] = -33759.9345356599
+ polycoefvector[1] = 157973.934412529