I'm working with a data frame that contains multiple layers; data frame and layers all use a GCS (WGS_1984). On one layer in particular, I want to be able to draw and measure the acreage of polygons. I know I can't measure acreage in a GCS, I would need to use a Projected coordinate system. What would be my solution? Project the desired .shp file into a PCS and then do a data frame transformation into the same PCS...? Is the project on the fly function alone enough to allow me to be able to accurately measure acreage and distance off of a GCS layer in a PCS data frame?
[I'm working at a VERY close-up scale, mapping out crop plantings at the feet/inches level, on a small city/county (Kauai, HI) scale. I'm using the NAD_1983_HARN Hawaii state plane for my PCS when applicable.]