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Poster Session
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Analysis of interpretation properties of forest lands
on various scale TM imagery
- In order to further analyze FRITP on VSTMIaccording to the minimum area of forest plot that can be practically interpreted and delineated as well as interpretation experience the number and total area of interpreted forest plots on TM images with 9 kind scales were arranged in Table 3 and a diagram e\was drawn for finding out the loss of FRIM on VSTMI
see table 3 and fig 5.
It can be seen from Table 3 and Fig.5 show that the along with reduction of TM image's scales, information of some small artificial forest plots loses continuously and their interpretation properties of forest lands reduce rapidly . The table 3 and fig 5 show that loss percentages of the FRIM is low on 1:500.000 and 1:200.000 scaled TM are 3.3 % and 14.2% respectively and the loss of total area of forest plots are 0.4% respectively but beginning at 1:250.000 scaled TM image the loss percentage of FRIM image increase rapidly along with the reduction of TM image scale. This shows that using 1:250.000 or smaller scaled TM image to carry out FRIT can not satisfy the precision requirements of forestry production in forest lack region with small artificial forests scatteredly distributed so these scaled TM images can only be used for reference materials.
Table 3. Statistical table of number and area of interpretable
forest plots on TM images 9 kind scales.
| Scale of TM iamge |
Minimum delineated area(ha.) |
Number of forest plots |
Total area(ha.) |
| 1 : 100,000 |
3.0 |
332 |
9225 |
| 1 : 150,000 |
4.5 |
321 |
9187 |
| 1 : 200,000 |
8.0 |
285 |
8970 |
| 1 : 250,000 |
12.5 |
218 |
8295 |
| 1 : 300,000 |
18.0 |
148 |
7584 |
| 1 : 350,000 |
24.5 |
87 |
6032 |
| 1 : 400,000 |
32.0 |
48 |
4967 |
| 1 : 450,000 |
40.5 |
22 |
4019 |
| 1 : 500,000 |
50.0 |
18 |
3842 |
Fig. 5 Diagram of loss percentages of forest information on variously scaled TM images.
- The above analysis results have displayed the extent of FRIM loss on VSTMI according to the previous experience of forest interpretation on variously scaled images and the examination results of CPIFP on 1:1000,000 and 1:200.000 scaled TM images it can be concluded that CIPFP are very close when the interpretation is carried out within the scope of respective minimum interpretable and delineative area of VSTMI therefore FRITP on several scaled TM images were reckoned on the basis of combination the mean of FRITP on VSTMI table 4 and fig. 6.
The Changing trend of FRITP of VSTMI can be from fig. 6 which can provide reference for optimum scale selection of TM image for conducting FRIT three North shelter forest region and to accomplish the purpose of meeting the precision requirement of forestry production and scientific research as well as reducing the raising working efficiency to make economic benefits[3].
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