GIS Application to Regional Geological Structure Relationship Modelling Considering Semantics

GIS modelling, which is often employed to establish the abstract structural forms of geological phenomena and their structural relationships, is of great importance for the expression and analysis of geological structures to describe and express such phenomena accurately and intuitively. However, current GIS modelling schemes value structural forms over structural relationships, and existing geological semantic expressions in the modelling of geological relationships are incomplete. Therefore, this paper categorizes geological relationships into three levels: geological phenomena, geological objects and geological spatial objects: (1) based on their definitions, this work categorizes geological relationships into internal composition relationships and external combined relationships for a total of two categories, eight classes and 27 small groups; (2) this work also improves the system with a total of 33 classified geological objects by transforming the relationships between geological phenomena into relationships between geological objects; and (3) based on the 27 small groups of geological relationships, through the corresponding geometric and semantic expressions between topological rules and geological rules and between relationship rules and geological rules, this work then expresses internal composition relationships as topological relationships between geological spatial objects and expresses external combined relationships as association relationships between geological spatial objects. A GIS model of geological relationships that integrates their geometries and semantics is then built. Finally, taking the Dagang-Danyang section of the Ningzhen mountains as an example, the results show that the proposed GIS modelling method can better store and express geological phenomena, geological objects and geological spatial objects in a way that integrates geometry and semantics

Measuring Human-Scale Living Convenience through Multi-Sourced Urban Data and a Geodesign Approach: Buildings as Analytical Units

Living convenience, as a perceptual quality of life, is gradually playing an increasingly important role in the context of seeking livable cities. A high degree of living convenience positively affects urban vitality, livability, and daily physical activities. However, it is hard to achieve a quantitative measurement of this intangible, subjective issue. This study presents a data-informed analytical approach to measuring the human-scale living convenience using multi-sourced urban data and geodesign techniques. Firstly, according to classical theories, living convenience is translated as the co-presentation of accessed number and diversity of urban facilities. Based on that, this study applies multi-sourced urban data, including points of interest (PoIs), buildings, and street networks, to compute the living convenience of each building in the 15 min community–life circle. Through the geoprocessing tools developed by ArcGIS API for Python (ArcPy), the living convenience of millions of buildings in an entire city can be computed efficiently. Kaifeng City from Henan Province, China, is selected as the case study, and the verification from local experts in urbanism shows high accuracy. The capacity to measure intangible perception exhibits the potential for this analytical approach in urban planning practices. Several explorations have been conducted in this direction, including analyzing the spatial heterogeneity in Kaifeng City and planning decision support for bus station arrangement. In short, this study contributes to the development of human-centered planning by providing continuous measurements of an ‘unmeasurable’ quality across large-scale areas. Insights into the perceptual-based quality and detailed mapping of living conveniences in buildings can assist in efficient planning strategies toward more livable and sustainable urbanism

Ocean surface currents estimated from satellite remote sensing data based on a global hexagonal grid

Global ocean surface currents estimated from satellite derived data based on a regular global grid are affected by the grid’s shape and placement. Due to different neighbourhood relationships, the rectangular lat/lon grids lose accuracy when interpolating and fitting elevation data. Hexagonal grids have shown to be advantageous due to their isotropic, uniform neighbourhood. Considering these merits, this paper aims to estimate global ocean surface current using a global isotropic hexagonal grid from satellite remote sensing data. First, gridded satellite altimeter data and wind data with different resolutions are interpolated into the centre of the global isotropic hexagonal grid. Then, geostrophic and Ekman currents components are estimated according to the Lagerlof Ocean currents theory. Finally, the inversion results are verified. By analyzing the results, we conclude that the ocean surface currents estimated based on the global isotropic hexagonal grid have considerable accuracy, with improvement over rectangular lat/lon grids

A web-based strategy to reuse grids in geographic modeling

Grids are essential for the production of geospatial data and environmental modeling. Over many years of research, numerous grids have been designed and developed. Reusing grids can reduce usage costs. However, there are still factors that impede grid reusability. Gridding algorithms are difficult to share and reuse on another device because most gridding algorithms have certain requirements for the devices’ operating system (Windows or Linux) and runtime environment (Python, C++, or C#). Additionally, grid data are organized into various formats by the gridding algorithms, and parsing schemes need to be customized prior to using the data based on the rules governing the data organization. However, data customization tasks are difficult to replicate. This article presents a web-based grids reusability strategy to mitigate the problems encountered when reusing gridding algorithms and grid data. To reuse gridding algorithms, a service-oriented gridding algorithm encapsulation method is studied. Based on this encapsulation method, heterogeneous gridding algorithm programs can be invoked as standard web services regardless of a device’s operating environment. Moreover, a grid data wrapping method is also studied in this strategy to assists algorithm users with parsing grid data in a unified manner and more easily access grid data on the web. Finally, a web-based prototype system is established to demonstrate the strategy’s effectiveness and viability reusability

Spatial Distribution of Global Cultivated Land and Its Variation between 2000 and 2010, from Both Agro-Ecological and Geopolitical Perspectives

Food security requires a thorough understanding of the spatial characteristics of cultivated land changes on a global scale. In particular, the spatial heterogeneity of global cultivated land changes needs to be evaluated with high spatial resolution data. This study aims to analyse the spatial distribution of global cultivated land and the characteristics of its variation, by using GlobeLand30 data for 2000 and 2010 with a 30-m spatial resolution. The cultivated land percentage and rate of cultivated land use change are calculated based on 18 agro-ecological zones (AEZs), 32 geopolitical and socioeconomic regions, and 283 world regions. The results show that (1) more cultivated land is located in regions under a temperate climate and moderate moisture conditions; (2) the percentage of cultivated land is related to the gross domestic product (GDP) and population, while increases and decreases in cultivated land are related to the rural population, policy encouragement, urbanization, and economic development; and (3) the percentage of cultivated land and rate of land use change within an AEZ vary greatly due to the different socioeconomic conditions, and the values within a geopolitical area also vary, due to different natural conditions

Extraction of ocean tidal information based on global equal-area grid and satellite altimeter data

Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids. With the increase of latitude, the traditional lat/lon grid deforms greatly, resulting in uneven distribution of satellite altimeter data with latitude, which affects the extraction of tidal information. Alternatively, Hexagonal grids have been proved to be advantageous due to their isotropic, uniform neighbourhood, equal-area and more. Considering the merits above, the purpose of this paper is to use the global equal-area hexagonal grid to conduct a harmonic analysis of satellite altimeter data. First, the Icosahedron Snyder Equal Area projection method is used to construct a global equal-area hexagonal grid, Then the time series data of 19.8 years of Jason series satellite altimeter data are obtained. Finally, the harmonic constants of eight constituents (the M2, S2, N2, K2, K1, O1, P1, Q1) are extracted by harmonic analysis. By analysing the results, we conclude that the harmonic constants extracted from the global equal-area hexagonal grid have considerable accuracy and are consistent with the tidal characteristics of the eight components. Meanwhile, the accuracy of harmonic constants extracted from equal-area hexagonal grids is better than that of lat/lon grids

Performance analysis of global HYCOM flow field using Argo profiles

Flow field data generated by ocean models are important for simulating ocean currents and circulation patterns, which are essential components in digital Earth construction. To evaluate the accuracy of model-simulated flow fields, Array for Real-time Geostrophic Oceanography (Argo) float observations can be considered benchmarks. In this study, a novel method for comparing Argo profiles with 3-dimensional trajectories obtained by simulating Argo floats in Hybrid Coordinate Ocean Model (HYCOM)-provided flow fields was proposed. Surface and subsurface trajectories were calculated, and their spatial matching characteristics were analyzed. The results demonstrated that (1) the HYCOM surface and subsurface flow fields generally conform to the basic characteristics and trends of ocean currents; (2) the HYCOM sea surface current field error pattern exhibits a symmetrical distribution centered on the equator in the Northern and Southern Hemispheres and increases with increasing latitude; and (3) the HYCOM subsurface flow field exhibits regional differences, with the largest differences in the Gulf Stream, North Atlantic Warm Current, and Westerly Wind Drift region. Through analysis of the disparities between HYCOM and Argo data, the effectiveness of using model simulation data can be enhanced, and the accuracy and dependability of ocean models can be improved

A loosely integrated data configuration strategy for web-based participatory modeling

Participatory modeling is an important approach for solving complex geo-problems from a comprehensive and holistic viewpoint, and it brings together stakeholders from multiple disciplines to provide diverse resources, including modeling, data fields and computational assets. Data configuration work (e.g., preparing appropriate input data for model execution, connecting a model’s output to the input data of another model) is important for constructing and executing a participatory modeling task. Most current data configuration methods depend on the model integration logic, which presents a challenge when adding new modeling resources into a model to dynamically create and execute new modeling tasks. To support the construction of participatory modeling tasks in a web environment, this article proposes a loosely integrated data configuration strategy for decoupling data configuration work from the execution process of a participatory modeling task. A model service controller is designed for model input/output (I/O) configuration, and a data service controller is designed for data access configuration. These two controllers can help modelers link the data I/O demands of a model-service with the appropriate data-services; thus, different modeling instances can be dynamically joined to a participatory modeling task and executed without reconstructing the original data configuration settings. A prototype participatory modeling system is proposed to demonstrate the flexibility and feasibility of the proposed method using an experimental modeling case. The results show that the proposed data configuration strategy supports the integration of different model-services based on the data dependency relationships and that the complexity and difficulty in configuring data for a participatory modeling tasks in the web environment are minimized