I know the Lavish Lifestyle of type of people living in DHA Karachi and the real value of property there, which even poor Canadian Visa Officers even cant think to afford.(so they think you are telling a lie). But since these visa officers are book worms, bookish, bias, subjective, robotic and clerical... they want to check your Tie to Pakistan, and property is one of the tie to convince them that you will come back, because you have monetary stakes. Valuation is necessary because their mindset is that in Canada they have concept of 20 years lease. Means, if someone has home in Canada worth even 1 Million Canadian Dollars, actually he is poor because you have just paid the little down payment and installments of few thousand dollars and you can live in that home!! So visa officers think same about you... (PS: even the 1 Million Dollar home there, is just because of the artificial bubble in the Property Market of Canada --but only in Toronto / Vancouver which can burst anytime)
So if you fully own a land or home in cities like Karachi, make the valuation of your property from some authentic valuer, its a better idea to have it done to remove the suspicions in the minds of visa officers. Tell the valuers you are doing this for visa purpose. The one to whom i talked he said that he will mention the estimated market value not the book value or govt value. Now its their little knowledge how they think, the govt value or market value. (its a common sense and they should know the difference between book value or market value, of even the value which someone has declared in tax assessment forms for the purpose of tax etc). In fact its a better idea to attach a last property tax paid challan with your application.
Let me tell you a very new point here, if you have more assets, properties and heavy cash in banks, there is also a probability that your visa may get rejected, because the biased, clerical, robotic, poor and subjective visa officers do think and are afraid ... that with so much of bank balance and money you can easily be settled in Canada .....and here it comes to their personal racism, bias and jealousy, so be careful...! Because same has happened with one of my friend.....!