Hydrological analysis of spatial analysis in ArcGIS

The Hydrological analysis function module for ArcGIS includes 11 tools, with names and functions:

1, Basin: basin analysis tools. Used to divide all basin basins in the study area.

Basin Basin is a catchment area divided by watershed. It determines all the grids that are interconnected and are in the same basin basin by analyzing the flow direction data. The determination of Basin Basin first is to determine the location of the outlet at the edge of the analysis window, that is to say, in the division of Basin Basin, the outlet of all basin basins are at the edge of the analysis window. When the location of the outlet is determined, the catchment area of the basin basin is similar to that of the Depression contribution area, that is to find out the location of all upstream rasters that flow into the outlet.

2, Fill: depression filling tool. Fill depressions on the raster data surface to remove minor flaws in the data.

Dem is considered to be a relatively smooth terrain surface simulation, but due to the reasons of interpolation and the existence of some real terrain, so that there are some concave areas of the DEM surface, then these areas in the surface flow simulation, due to the existence of low elevation, Thus, in the calculation of flow flow in the region can not get a reasonable or wrong flow direction, so before the calculation of the flow direction, the DEM data should be first in the depression to fill, to obtain a non-depression dem.

3, Flow accumulation: traffic tools.

In the process of surface runoff simulation, the confluence accumulation is calculated based on the flow direction data. For each raster, the size of its catchment accumulation represents the flow direction of how many rasters upstream it flows through the grid, and the greater the value of the confluence, the more prone to surface runoff in the region.

4. Flow Direction: Flow direction tool.

It is also called D8 algorithm to determine the flow of water based on the maximum distance between each cell and its nearest eight cells, and to obtain a raster of the flow direction.

5. Flow length: Water flow lengths tool.

The length of the water flow is usually the projection length on the horizontal plane of the maximum ground distance between a point along the flow direction to its starting point (end point) on the ground.

6. Sink: The calculation tool of depression.

A depression area is a place where the direction of the flow is unreasonable, and the direction of the flow can be used to determine where the depressions are and then to fill the depressions. It must be clear that not all of the depressions are caused by the error of the data, many of the depressions are the true reflection of the surface morphology, so before the depressions are filled, the depth of the depressions must be calculated to determine which areas are due to the data errors caused by the depressions and which regions are true surface forms, Then, in the process of filling the depression, set a reasonable fill threshold.

7. Snap pour point: Snap pour points tool.

The cell that captures the largest amount of traffic within the defined range is the pour point.

8, Stream link: River Connection tool.

Stream Link is a record of the connection information between some nodes in the river network, which mainly records the structure information of the river network. Each arc of Stream link is connected with two nodes as a point of outlet or junction, or connected to the node and the start point of the River network as the outlet point. Therefore, by the Stream link calculation, we get the starting and ending points of each river network arc segment. Also, the outlet of the catchment area can be obtained.

9, Stream Order: River Network Grading tool.

A stream hierarchy is a method of assigning levels to connectors in a river network. This level is a method of identifying and classifying river types based on the number of tributaries. You can infer certain characteristics of a river only by knowing the level of the river.

10, Stream to Feature: Grid River network vectorization.

Converts the raster type of a river network to a vector type.

11, Watershed: Watershed tool. Used to generate a watershed raster.

A watershed is an uphill area where a fluid (usually water) is pooled into a public outlet so that it is centrally discharged. It can be part of a larger watershed or a smaller watershed known as a natural sub-watershed. The boundary between the watersheds is called the watershed dividing line. The outlet or pour point is the discharge point of the surface water. It is the lowest point on the watershed boundary.

Hydrological analysis of spatial analysis in ArcGIS