Fig.1

Comparison of the number of nodes on contour lines at different scales"

Fig.2

Node density distribution of contour lines at different scales"

Fig.3

Scale judgment of terrain vector data coupled with knowledge and algorithm"

Fig.4

Summary results of ground features with Fc=2 and Fc=1"

Fig.5

The upper limit determining principle of node density range"

Fig.6

Node density for each line segment of a 1∶50 000 water system map"

Fig.7

Density distribution of nodes in various line segments of a 1∶50 000 water system map before and after outliers deletion"

Tab.1

Normal distribution test results of original 1∶250 000 water system node density data"

Tab.2

Normal distribution test results of 1∶250 000 water system node density index after logarithmic conversion"

Fig.8

Node density and node density index distribution of 1∶250 000 water system sample data before and after logarithmic conversion"

Fig.9

The cross region processing"

Fig.10

The flowchart of scale determination"

Fig.11

Normal distribution of node density index of contour lines with different scales"

Fig.12

Normal distribution of node density index of water system with different scales"

Tab.3

and μ' value statistics of contour lines with different scales"

比例尺		μ'	2μ'-
1∶5万	1	1.42	1.84
1∶25万	1.60	2.08	2.56
1∶100万	2.28	2.77	3.26

Tab.4

and μ' value statistics of water lines with different scales"

比例尺		μ'	2μ'-
1∶5万	1.18	1.58	1.98
1∶25万	1.78	2.28	2.78
1∶100万	2.45	2.92	3.39

Tab.5

Node density index intervals of contour lines and water system elements at different scales under the constraints of natural laws"

Tab.6

The accuracy of the scale of 1∶1 000 000 terrain vector features"

Tab.7

The accuracy of the scale of 1∶250 000 terrain vector features"

Tab.8

The accuracy of the scale of 1∶50 000 terrain vector features"

Tab.9

Statistics on the accuracy of the terrain vector features scale determination"