Table 2. Results of area sampling with non-updated area sampling frame.

Five strata were defined according to the cotton-to-non-cotton area ratio in each grid unit.

Stratum number	Total no. of area frames (Nh)	Weight (fh)	Variance of each stratum ($S_h^2$)	No. of sampled area frames (nh)	Mean value of sampled area frames	Variance of sampled area frames ($s_h^2$)	$\left(1-f_h\right)∕n_h$	$\left(\left(1-f_h\right)∕n_h\right)\times s_h^2\times N_h^2$	Total crop area ($\hat{Y}$) (Sampling Units, 0.09 km2)	CV	NELUCI
1	772	0.3351	0.0023	8	0.1650	0.1092	0.1237	8050.4401	1337.5893	0.0711	0.1373
2	207	0.0898	0.0032	2	0.4500	0.0242	0.4948	513.0721
3	266	0.1155	0.0033	3	0.7700	0.0016	0.3299	37.3434
4	496	0.2153	0.0031	5	0.7760	0.0020	0.1979	96.4075
5	563	0.2444	0.0047	6	0.9367	0.0064	0.1649	335.9725