River full-water-area water surface width measuring and calculating method and system

Abstract

The invention discloses a river full-water-area water surface width measuring and calculating method and a river full-water-area water surface width measuring and calculating system. The method comprises the steps of obtaining a riverway remote sensing image; determining a set formed by a plurality of straight lines passing through the target points in the riverway in the riverway remote sensing image as a target straight line set; determining a straight line pixel point coordinate set of each straight line in the target straight line set based on a preset maximum detection river width threshold and the target point in the river channel; calculating pixel coordinates of a left intersection point and pixel coordinates of a right intersection point of each straight line in the target straight line set based on the straight line pixel point coordinate set; calculating the pixel point distance between the pixel coordinate of any one left intersection point corresponding to each straight line and the pixel coordinate of any one right intersection point, and determining the minimum pixel point distance as the straight line distance between two banks of the corresponding straight line; and determining the smallest one of the linear distances between the two banks as the river width passing through the target point in the river channel. According to the invention, high-efficiency and high-precision measurement and calculation of large-range and dynamic river width are realized.

Description

technical field [0001] The invention relates to the field of remote sensing image analysis and photogrammetry, in particular to a method and system for measuring and calculating the water surface width of the whole water area of ​​a river. Background technique [0002] Surface river surface width (river width) is one of the important hydrological parameters, which is closely related to surface runoff. Large-scale and long-term river width measurement based on remote sensing data is helpful to study and grasp the change law of surface runoff, and is of great significance for runoff monitoring and flood monitoring in areas with no or little data. [0003] The measurement of surface river width has always been a hot spot in remote sensing hydrology research. The commonly used definition of surface river width is to draw a vertical line across the center line of the river, and the distance between the vertical line and the intersection point of the two banks is the river width ...

AI Technical Summary

Problems solved by technology

Based on this definition, there are currently several measurement methods: The RivWidth tool extracts the centerline of the river channel and calculates the channel width based on the Laplacian convolution algorithm. Using this method, the Global River Widths from Landsat (GRWL), a major river width data set in the world, has been constructed. ;Based on the RivWidthCloud tool developed on the Google Earth Engine (GEE) platform, this tool improves the discontinuity of the centerline of the river channel extracted by RivWidth, but the same as RivWidth, the river width calculation method at the intersection of the river channel is invalid, and it is not applicable to other than Landsat. Remote sensing data; RivaMap software developed based on the singularity analysis method of water body images, and a calculation method based on the singularity index (singularity index) of the river channel width, which also has the failure to calculate the river width at the intersection of the river channels; using the SRTM elevation data to adopt the center The method of the shortest distance from the line to the river bank extracts the width of large rivers in the world, but this method needs to remove the influence of sandbars and islands in the river channel, so the width measurement of some rivers such as braided rivers is inaccurate

[0004]The existing river width measurement methods have the following problems: (1) The existing methods rely on the accurate extraction of the channel centerline when calculating the river width, and the extraction of the channel centerline The error will be propagated to the river width measurement result, thus increasing the uncertainty of the river width measurement

[0005] In summary, the measurement of river width in traditional methods is not an independent problem, but depends on the accurate extraction of the centerline of the river channel. To simplify the calculation, the existing The method ignores the river crossing or the existence of sandbars and islands to extract the river width, which makes the measurement of the river width inaccurate

Images