A vacant Land / Raw Land valuation thoughts?

[Karl James]

I am trying to estimate the market value of a 2 acre, land locked parcel of land.  It is in the midst of a 20+ acre undeveloped area that is bound on two sides by nice residential developments ( 3 bedroom / 3 bath) brick homes where there is a good deal of new construction activity. I can easily get good comps for the vacant, ready to build, lots in these developments.  But there is not recent sales or listings of undeveloped raw parcels nearby.

Does anyone have thoughts on a decent factor to apply to developed parcels to estimated undeveloped land value?  For example,  if a vacant ready to build 1/4 acre lot is worth $25k or $100k per acre, is undeveloped land nearby that is prime for development worth 10% of the post-development land value? Or more, less?

The land is in the growing southwest Houston, TX area.  Any developers or others on BP with ideas of guesstimates or rules of thumb to interpolate?

Thanks,

Karl