Surface Current Visualization in Waterway Based on Mike 21 Model

and S-100 Standards

Zixuan Wang, Mingyang Pan

, Shaoxi Li, Chao Li and Zongying Liu

Navigation College, Dalian Maritime University, Dalian, Liaoning, 116026, China

Keywords: S-100, Mike 21, Surface Current, Marine Data Standards.

Abstract: The S-100 standard, proposed by the International Hydrographic Organization (IHO), aims to address the

limitations of the S-57 standard in terms of data application and interoperability. This study focuses on the

Fujiangsha water area, using the Mike 21 hydrodynamic model to simulate the flow dynamics in the region.

The standardized processing of this data generates S-111 surface current data that complies with the S-100

specifications. The visualization of surface current data is realized using Cesium, which displays the flow

field characteristics of the Fujiangsha water area. By integrating the standardization of S-111 data with

visualization technology, this paper seeks to provide new technical support and application demonstrations

for maritime management and navigation safety, while exploring the potential for further development of the

S-100 standard in practical applications.

1 INTRODUCTION

The S-100 Universal Hydrographic Data Model is a

new generation of marine geographic information

standard officially established by the International

Hydrographic Organization (IHO) in 2010. It aims to

address the limitations of the S-57 standard in terms

of data application and interoperability, facilitating

data fusion and sharing (Luo, J. N. et al., 2019). S-

100 covers electronic charts and various marine

environmental information data products, enhancing

the visualization and application of dynamic

hydrological data. Its product specifications (such as

S-101 electronic charts, S-102 bathymetric surfaces,

S-111 surface currents, etc.) provide technical

support for navigation safety and efficiency,

becoming a crucial foundation for modern marine

surveying and mapping(Wu, L. L. et al., 2019).

However, current research on S-100 remains

largely theoretical (Peng, W. et al.,2017; Dou, H. X.,

2013; Liu, Q. C.,2012), with limited studies focused

on its practical applications, particularly in the area of

channel information visualization. To address this

gap, this paper takes the Fujiangsha water area as the

study subject, generating surface current data that

complies with the S-111 standard through

Corresponding author

standardized processing. These data are derived from

simulations of the channel flow field using the Mike

21 hydrodynamic model, which provides

hydrodynamic characteristic data of the region,

including high-resolution data on water flow speed,

direction, and other parameters. To further

demonstrate and apply these data, a front-end

platform based on Cesium was developed, and the

surface current data were visualized, providing an

intuitive representation of the flow field

characteristics in the Fujiangsha water area.

2 METHODOLOGY

2.1 S-111 Data Structure

Surface current data in the S-111 standard can be

represented in two formats: point data contained

within a regular grid and point sets described by an

irregular grid. Based on the source of surface current

data, it can be categorized into four basic types:

observed or predicted values at multiple fixed

locations, predicted values arranged in a regular grid,

values at multiple locations but not within a regular

grid, and values observed at mobile stations. In this

Wang, Z., Pan, M., Li, S., Li, C. and Liu, Z.

Surface Current Visualization in Waterway Based on Mike 21 Model and S-100 Standards.

DOI: 10.5220/0013466000003935

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 11th International Conference on Geographical Information Systems Theory, Applications and Management (GISTAM 2025), pages 231-235

ISBN: 978-989-758-741-2; ISSN: 2184-500X

231

study, the surface current data type is predicted values

arranged in a regular grid.

The S-111 regular grid is an implementation of

S100_GridCoverage. A regular grid is a two-

dimensional orthogonal spatial grid defined by

several attributes, including the grid origin, spacing,

and grid indices. The velocity and direction of surface

currents correspond to the nodes within the regular

grid. The grid values are stored sequentially along the

X-axis at the lowest position of the Y-axis, starting

from the leftmost value and proceeding to the next X-

axis values for each subsequent Y-axis position until

the top of the Y-axis is reached. A typical regular grid

and its parameters are illustrated in the figure 1.

Figure 1: Typical structured grid and its parameters.

According to the S-111 Surface Current Product

Specification of the IHO-released S-100 series

product standards, surface current data products must

be encoded using the Hierarchical Data Format

version 5 (HDF5). The HDF5 data format is capable

of efficiently organizing massive amounts of data

through its inherent structural features. Typically,

files adopt a hierarchical tree structure, where the

nodes of the tree are Groups, representing collections

of objects. Each group contains one or more Datasets,

which are multidimensional data arrays that include

attributes and other metadata. The structure of an

HDF5 file is shown in the figure 2.

Figure 2: HDF5 file structure.

According to the mandatory naming conventions

outlined in the S-100 standard, the following groups

and data names are required in the S-111 data

product: Group_F, featureCode, SurfaceCurrent,

axisNames, Positioning, SurfaceCurrent.nn, and

Group_nnn (n is an integer from 0 to 9). The figure 3

illustrates the structure of example S-111 data

provided by the UK Hydrographic Office.

Figure 3: Structure of the UK Hydrographic Office's S-111

example data

2.2 S-111 Visualization Representation

The S-111 Surface Current Product Specification

provides detailed guidelines for the display of surface

current data. The grid data of the surface current field

is depicted using multiple arrows. These arrow

symbols are created using Scalable Vector Graphics

(SVG) instructions, following the input specifications

shown in the figure 4, and are scaled according to the

surface current speed and the display area.

Figure 4: Input specifications for S-111 arrow symbols.

The direction of the arrow symbols must represent

the direction of the surface current flow (referencing

true north). The color of the arrows must be based on

the speed values of the data, with the opacity adjusted

according to the background chart. The size of the

arrows must be a function of the surface current

speed, where

ref

and

ref

are used as reference

values for scaling the arrows. The minimum and

maximum speed values,

low

and

high

, are used to

calculate the length of the arrows. The surface current

with a speed of

is represented by an arrow with a

height of

. The calculation method is as follows:

()

{

}

,, /

ref low high ref

HminmaxSSS S=⋅

(1)

The arrow symbols are placed over a

geographically referenced background, and when the

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232

cursor hovers over the vector arrows, the

corresponding speed and direction values for each

arrow are displayed. The figure 5 shows an example

of S-111 data from the UK Hydrographic Office,

visualized using the KHOA S-100 Viewer.

Figure 5: Visualization of the UK Hydrographic Office's S-

111 example data.

2.3 Mike 21 Hydrodynamic Model

Mike 21 is a two-dimensional numerical model

developed by the Denmark Hydraulic Institute,

providing a comprehensive and efficient design

environment for engineering applications, coastal

management, and planning. Mike 21 is not only

beneficial for simulating complex river channels but

also supports a variety of control structures. Its

relatively short computation time significantly

improves computational efficiency(Li, X. B., 2024).

Thus, this study uses the Mike 21 to simulate the

channel flow field and further construct the

hydrological characteristic dataset for the channel

flow field.

Mike 21 neglects vertical flow acceleration and

focuses on vertically averaged flow factors. It can use

either Cartesian or spherical coordinates, and in the

plane, it employs unstructured grids to simulate water

level and flow variations caused by various forces, or

to model two-dimensional free-surface flows that

disregard stratification. The numerical method used

in Mike 21 is the finite volume method, which

computes the normal fluxes by establishing a unit

hydraulic model along the outer normal and solving

the one-dimensional Riemann problem(Lü, Z. Y.,

2024). The specific equations of the two-dimensional

shallow water equations in the Mike 21 are as follows:

hhuhv

tx x

∂∂ ∂

++=

∂∂ ∂

(2)

Momentum Equation in the X Direction:

()

00000

asxbx

xxys

hu hu huv

fvh gh

txy x

hp gh

hT hT hu S

xy x y

ρτ τ

ρρρρρ

∂∂ ∂ ∂

++=− −

∂∂ ∂ ∂

∂∂

−+−−

∂∂

∂



∂∂∂

++ + +



∂∂ ∂ ∂



(3)

Momentum Equation in the Y Direction:

() ()

00000

sy by

yx yy

yyys

hv hv huv

fuh gh

ty x y

hp gh

hT hT hv

xy x y

ττ

ρρρρρ

∂∂ ∂ ∂

++ =− −

∂∂ ∂ ∂

∂∂

−+−−

∂∂



∂∂

++ + +



∂∂ ∂ ∂



(4)

The average flow velocity along the water depth

direction is defined by the following equation:

hu udz hv vdz

ηη

−−



(5)

Where

is Riverbed elevation;

,uv

is velocity

component in the direction

;

is average

water flow velocity in the direction

;

coriolis force coefficient;

is Earth's rotational

angular velocity;

is local latitude;

gravitational acceleration;

is flow generated by

source and sink terms;

,,,

xbxsyby

ττττ

components of the surface wind stress and riverbed

bottom friction stress along the direction

;

lateral stress terms.

The boundary condition treatment in the MIKE 21

includes open boundaries, closed boundaries, and

dry-wet boundaries. Under open boundary

conditions, water flow is allowed to enter and exit the

boundary region. For closed boundaries, all velocity

components perpendicular to the boundary are set to

zero, defining a no-slip boundary. In dry-wet

boundary conditions, the cells are classified as dry,

semi-dry, or wet, with the conditions being satisfied

as:

dry flood wet

hh h<<

( Hu, X. W., 2024).

Surface Current Visualization in Waterway Based on Mike 21 Model and S-100 Standards

233

3 EXPERIMENTS

3.1 Two-Dimensional Flow Field

Calculation

The Fujiangsha Waterway is located opposite the

Zhangjiagang Port area.In this study, MIKE 21 is

used to construct a two-dimensional hydrodynamic

numerical model for the river section where the

Fujiangsha Waterway is located. The river section is

approximately 43 km long. The computational range

of the model is shown in the figure 6.

Figure 6: Model computation range.

In constructing the model computational grid, it is

necessary to extract the riverbank and water depth

data. In this study, ArcGIS Pro was used to extract

riverbank and water depth data from the S-57 charts.

Given the characteristics of the river channel, an

unstructured triangular mesh grid was employed. The

grid near the riverbanks and islands was refined,

while the grid in the center of the river was coarser,

ensuring the model’s stability and improving

computational efficiency. The computational grid

consists of 1,277 nodes, which is shown in the figure

Figure 7: Model grid division.

The MIKE 21 model adopts a cold start for its

initial conditions. The upper and lower boundary

conditions are defined as water level boundaries, with

the boundary format varying over time and along the

boundary. In this study, the default value of 0.28 is

used for the eddy viscosity coefficient. The Manning

coefficient is selected to control the bed roughness,

set to 32 in this study. The time step is set to 300

seconds, with results output every 30 minutes. The

model's computational results are shown in the figure

Figure 8: Model computation results (time interval of 4).

3.2 S-111 Data Generation and

Visualization

Based on the results from MIKE 21, this study uses a

script to perform interpolation and gridding of flow

velocity and direction data, generating surface current

data files compliant with the S-111 standard. The

domain of the regular grid is defined by the latitude

range from about 31.93 N to 32.08 N and the

longitude range from about 120.24 E to 120.70 E,

with a grid resolution of 0.001. The interpolation

method is used to map irregularly distributed data

points onto a regular latitude-longitude grid.

Subsequently, the gridded data is further processed to

generate a surface current data file in HDF5 format.

The interpolated data file is loaded, and the flow

velocity and direction data are reconstructed into two-

dimensional arrays. Geographic boundaries,

resolution, and grid dimensions are then defined,

ensuring consistency with the settings in the

interpolation step. The resulting S-111 surface current

is shown in the figure 9.

Figure 9: Generated S-111 surface current data.

Based on the Cesium platform, this study

develops a frontend platform for data reading and

visualization, allowing complex current velocity and

direction data to be presented in an intuitive manner.

The platform reads the HDF5 files, parses the current

velocity and direction data into two-dimensional

arrays, and converts them into vector format. The

display of arrows is defined according to the S-111

surface flow product specifications, including

parameters such as color, size, and direction. The

visualization of the S-111 surface current is shown in

the figure 10.

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234

(a) (b)

Figure 10: Visualization of S-111 surface current data (a)

and its zoom-in (b).

4 CONCLUSIONS

This study focuses on the Fujiangsha and successfully

generates surface current data compliant with the S-

111 standard, based on the S-100 framework and the

Mike 21 hydrodynamic model. The data is visualized

using Cesium for intuitive display. The research

results demonstrate that the integration of

standardization and visualization techniques provides

a clearer representation of the hydrological

characteristics in complex water areas, offering

support for improving channel management and

navigation safety. However, it should be noted that

the S-100 standard has not yet been officially

implemented, and the current study area lacks

validated observational data. Future research could

refine the MIKE 21 model parameters using actual

hydrological measurements when available, thereby

enhancing the accuracy of simulation results. The

standardized data processing framework and

visualization scheme proposed in this study have

demonstrated applicability to compliant hydrological

data, which may serve as a reference for establishing

operational systems in standardized maritime

environments.

ACKNOWLEDGEMENTS

We would like to thank the National Natural Science

Foundation of China (NSFC) [grant number

52371363] for their funding.

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