Obtain high_cross and low_cross based on the shape of the road.

: How to obtain high cross and low cross based on the shape file of the provided Road

The so-called high cross is the King St path in the figure, and low cross is the gravers ln path.

The specific implementation method is as follows:

#1 import the shape data of the road to SQL Server

#2 add two fields low_cross and high_cross in the object table

#3 use a program [I use C # To write a small program] to cycle every street and find the path to the current Street, obtain the longitude and latitude of the current road start point address and the longitude and latitude of an intersection. Compare the distance between the start point and the intersection. The closer to the number is low cross, high cross is far from a small number.

#4 of course, there are many situations in the processing process: there is only one intersection-only one high cross or low cross can be updated

Both intersections are in the same direction -- this requires the intersections method to obtain the intersection comparison, and then the stequals method is used to compare whether the two intersections are the same point.

There are three intersections, four intersections, and five intersections. The processing method is the same. Currently, we cannot distinguish between high cross and low cross, therefore, there may be multiple high cross or low cross cases.

Obtain high_cross and low_cross based on the shape of the road.