\psset{arrowscale=2}
\pstGeonode[PosAngle=-135](-1.5,-.2){A}(.5,.2){B}(0,-2){D}
\pstRotation[PosAngle=90, RotAngle=60, CodeFig=true,
             CodeFigColor=blue,
             TransformLabel=\frac{\pi}{3}]{A}{B}[C]
\pstRotation[AngleCoef=.5, RotAngle=\pstAngleAOB{B}{A}{C},
             CodeFigColor=red, CodeFig=true,
             TransformLabel=\frac{1}{2}\widehat{BAC}]{A}{D}[E]