Route planning on orienteering maps with least-cost path analysis

The feature categories of an orienteering map are prepared to allow the map reader to estimate the travel time between any two points on the map with a good approximation. This requires not only an accurate map, but also a key that adapts to the speed of travel. Such map key is developed and maintained by the IOF (International Orienteering Federation), and technically all the orienteering maps are compiled by using it. Estimated time also plays an important role in planning the courses of orienteering races. The course setter estimates time based on a route he thinks is ideal, but the speed of travel is basically a non-linear function of terrain, road network and land cover. Because of this, the easiest (ideal) route between the two points and its time cost can be calculated using the least-cost path (LCP) GIS method, which can be prepared to take into account these three map feature categories. This method is based on the calculation of a cost surface, then the analysis of the ideal path from a given point to the destination. The automation can be adapted to any orienteering map due to the similarities of the map keys. This study shows that if the weight corresponding to the different feature categories is given properly, the ideal path between two points on orienteering maps can be calculated. The ideal path, however is still a subjective category, which may depend on the capabilities and preferences of the orienteer. In this study the routes calculated with the LCP method were compared with the suggestions of the ideal routes by orienteering runners of different ages. The results show that the routes given by sportsmen can be simulated with the LCP method and even the time cost of the calculated routes can be calculated. This study can lay the groundwork for a GIS tool helping the course setting process on standard orienteering maps.

Digital Navigator on the Seas of the Selden Map of China: Sequential Least-Cost Path Analysis Using Dynamic Wind Data

During the age of sail-powered ships, the maritime trade networks of Southeast Asia were highly cyclical in nature due to the biannually switching wind directions of the East Asian Monsoon. The Selden Map of China provides us with a glimpse of these connections in the early seventeenth century, and it is drawn in a unique way that allows the sailing durations between ports to be measured. In this paper, a novel method of simulating directed sail-powered voyages is developed. The method utilizes ArcGIS Pro’s functionality through Python macros, and unlike the previous least-cost path (LCP) sailing models, it is based on sequential LCP analysis using dynamic real-time series wind data. The optimized routes and sailing durations generated by the macros are then compared against the Selden map. In general, the model performs reasonably well in favourable winds, but is unable to simulate tacking properly in adverse conditions. The results allow the visualization of wind patterns in terms of time spent at sea and demonstrate the inherent natural rhythm of maritime movement and trade in the South China Sea region. The macros are freely available and can be modified to simulate directed sailing in other time periods, localities, and environmental settings.

Developing large-scale international ecological networks based on least-cost path analysis – a case study of Altai mountains

Habitat fragmentation and loss of landscape connectivity have resulted in the degradation of natural ecosystem services. Identifying international transboundary ecological network is an integrated approach to maintain regional ecological sustainability. In this study, taking Altai Mountains as a case study area, we suggested a set of procedures to construct an ecological network. First, we identified ecological patches by evaluating the values of the protected area. Second, we generated resistance surfaces based on the land cover characteristics. Third, we integrated habitat patches and resistance surfaces to identify potential corridors using the least-cost path analysis. The ecological network we introduced consists of 22 patches, 65 potential ecological corridors, and 5 stepping-stones. Furthermore, 26 ecological fragmentation points were marked. We proposed to carry out efficient and effective international cooperation between China, Russia, Kazakhstan, and Mongolia. In addition, the installation of road-crossing structures should be taken into consideration to minimize the negative impacts of the road-related disturbances.

A Least Cumulative Ventilation Cost Method for Urban Ventilation Environment Analysis

The correct urban building layout is an important influencing factor in urban ventilation, and the heat island effect has become an important factor affecting the quality of urban life. Optimization of the urban building layout can play a role in mitigating the heat island effect. The traditional ventilation corridor analysis method, based on a least-cost path analysis, can only generate a few main ventilation corridors. It is difficult to obtain global ventilation results covering the whole study area using this method of analysis. On the basis of urban morphology and a least-cost path analysis, this study proposes a “least cumulative ventilation cost” method for analyzing urban ventilation. Taking Wuhan downtown as a research area, the urban ventilation environment under different wind directions and seasons was analyzed. This method can effectively express the ventilation conditions throughout the whole study area and can simultaneously express the quality of the generated corridors effectively. The results show that Wuhan has three levels of ventilation corridor. Moreover, the ventilation conditions in Wuchang (Wuchang, Qingshan, and Hongshan) are better than those in Hankou (Qiaokou, Jianghan, and Jiang’an).