The fifth area is farming and agriculture land
2- The second method is depending upon Near-infrared at red reflectance (IR/R) and the algorithm for this method was:


The last mathematical model was founded and used to extract the green space, and the next images show the green areas that extracted by two methods (A) and (B) from second area that located at the center of Nanjing city.


In the (B) method we have seen green information of test area then parts of non-green space appeared and it need to be eliminate, but when we making model to comber the two methods as difference between (B) and (A) {(B)-(A)}, we have founded that many pixels are belong to green space and few of them belong to non-green space and the following images show the difference.



The next images have shown non-green space:

The result:
After the two extraction methods used, we obtain two kinds of maps describing the green space at five areas in Nanjing one of them is an agriculture land, the following tables and charts give the idea about the percentage of the green space for each area, finally it tells about the green space area from the total test area.

green space by pixel and there ratio from the area
1	Green space	Remaining	total area	Ratio	Green space difference1	Images difference2
A	629584	3087272	3716856	0.169386169	75088	85196
B	704672	3012184	3716856	0.18958819
2	green space	Remaining	total area	Ratio	Green space difference1	difference2
A	105750	2363850	2469600	0.0428207	7425	13725
B	113175	2356425	2469600	0.045827259
3	green space	Remaining	total area	percentage ratio	Green space difference1	difference2
A	94214	3081607	3175821	0.02966603	13872	18207
B	108086	3067735	3175821	0.034034034
4	green space	Remaining	total area	Ratio	Green space difference1	difference2
A	168000	3914400	4082400	0.041152263	22800	29600
B	190800	3891600	4082400	0.046737213
5	green space	Remaining	total area	Ratio	Green space difference1	difference2
A	4096597	12883184	16979781	0.241263241	272322	541282
B	4368919	12610862	16979781	0.257301257