Shunfu Hu

Multimedia Mapping on the Internet Using Commercial APIs

Multimedia mapping provides a unique approach to integrating geospatial information in digital map format and multimedia information (e.g., text, photographs, sound, and video). Multimedia mapping on the Internet is the direct result of advancement of Web mapping techniques, Internet technology, and Web standards (e.g., HTML, XML, Ajax). However, like traditional Internet GIS applications, multimedia mapping on the Internet is suffered from slow response time, limitation of data sizes, and the slow client/server communications. In addition, the development of multimedia mapping on the Internet requires a huge investment of computer hardware and software, and a steep learning curve for the application developer to become knowledgeable about all of the components involved. It is imperative that a better solution is needed to implement multimedia mapping projects on the Internet. This chapter discusses a new approach of multimedia mapping that utilizes commercial Application Programming Interface (APIs) such as Google Maps API, Yahoo! Flickr API, and YouTube API that can provide faster response time, greater user interaction, as well as higher quality multimedia presentation. A case study of an online visitor guide for the campus of Southern Illinois University Edwardsville is demonstrated.

Flood Simulation with Distributed Hydrological Approach Using DEMs and Remotely Sensed Data

The spatial variability of both meteorological and geographic features has a great influence on rainfall runoff process. When making flood forecasting, the influence of this variability on runoff should be considered. In this paper, the distributed hydrological modeling technique was adopted to simulate flood discharge with consideration of spatial variability using DEMs and remotely sensed data. In our approach, the grid based digital elevation data was used for the presentation of watershed discretization and deriving flow path system and parameters. The infiltration and rainfall excess on each hillslope grid cell were calculated using the Green-Ampt infiltration equation. Soil lateral flow was estimated based on Darcys law and continuity equation, overland and channel flows were calculated by using one-dimensional kinematic wave equations on hillslope and channel grid cells respectively. The land use and land cover data derived from remotely sensed images was used for the determination of Mannings roughness coefficients. The soil type data was used for deriving soil hydraulic parameters needed for calculation. The approach was applied in Jiaokou Watershed with area of 259 km2, a sub-basin of Yongjiang River in Zhejiang Province, China. The data collected for this study included land cover processed from Landsat TM images, soil type distribution from the soil maps, and 100-m spatial resolution DEMs produced from digital topographic maps. Spatial distribution of rainfall for each flood event was calculated by using distance inverse interpolation methods. Nine flood events were simulated, two of which were used for calibration, and the others for validation. The simulated hydrographs at basin outlet showed good agreement with observed ones for both calibrated and validated flood events, and average coefficients of efficiency were 94% for calibrated flood events and 92% for validated flood events.

Evaluation of Geo-Tagged Photo and Video Logging Methods to Collect Geospatial Highway Inventory Data

For many years, state departments of transportation (DOTs) and local agencies have collected and maintained highway inventory data (HID) to assist the decision makers at different levels. In light of the implementation of the recently published Highway Safety Manual (HSM) in 2010, many state DOTs have sought to tailor the various safety measures and functions to evaluate the safety in their jurisdictions. Insufficient HSM-required HID in many current DOTs’ databases, however, necessitates the collection of the absent features. To obtain these data, various techniques for different purposes have been used, including field inventory, photo and video log, integrated Global Positioning System/geographic information systems (GPS/GIS) mapping systems, aerial photography, satellite imagery, terrestrial laser scanners, airborne light detection and ranging (LiDAR), and mobile LiDAR. Among many data collection methods, the photo and video log is widely employed by DOTs due to its simplicity and low cost. Therefore, the focus of this article, which is a timely and needed research effort, is to evaluate the capability of the photo and video logging method to collect HID for supporting HSM implementation through a comprehensive literature review, a nationwide survey, and a field trial. The results of this study demonstrate that the photo and video log can provide worthy and relevant HSM data sets with acceptable accuracy.

Effect of DEM Uncertainty on the Distributed Hydrological Model TOPMODEL

TOPMODEL is a semi-distributed hydrological model in which the distributed predictions of catchments response to rainfall are made. In this process of simulation, digital elevation models (DEM) is required to provide the values of parameters, such as topographic index, cumulative area of catchment and distance from catchment outlet; thus DEM play a dominant role in TOPMODEL implementation. Generally, DEM has inherent errors, referred to as DEM uncertainty. Lacking of knowledge about DEM errors, DEM data is often used in hydrological applications by using TOPMODEL without quantifying the effects of DEM uncertainty. In fact, the uncertainty of DEM may strongly influence the simulation results produced by TOPMODEL. Unfortunately, this effect is largely ignored in many empirical researches. This study aimed to examine the impacts of DEM uncertainty on the simulation results of TOPMODEL from the study area - Jiaokou watershed, a sub- basin with an area of 259 km2 of the Yongjiang River in southeast China. This paper mainly discussed the effects in both quantitative and qualitative aspects. First, DEM uncertainty was simulated using the Monte Carlo method, and for every realization of the DEM, the topographic index, cumulative area of catchment and distance from catchment outlet were calculated. Second, TOPMODEL was tested and the results saved as the four statistical indices of the simulation: EFF (the Nash and Sutcliffe efficiency criterion), SSE (Sum of squared residuals over all time steps), SLE (Sum of squared log residuals over all time steps) and SAE (Sum of absolute errors over all time steps) under the condition of seven storm events. Third, the statistic results - min, max, range, standard deviation, and Mean Value, of the four indices from the simulated DEM were compared in each case of flood and Mean value of the four indices were picked up to evaluate the effect of uncertainty of DEM on TOPMODEL. Finally, the simulation hydrographs were compared with the hydrographs using the original DEM under each flood event. The biggest errors for the indices of EFF, SSE, SLE, and SAE were 0.0169, 2.3x10-5, 1.1375, and 0.0033 respectively, which showed that the effect of DEM uncertainty on TOPMODEL was inconsiderable and could be ignored in the models application.

Web-based Multimedia Mapping for Spatial Analysis and Visualization in the Digital Humanities: a Case Study of Language Documentation in Nepal

There has been a growing interest in utilizing geographic information systems (GIS) in the digital humanities and social sciences (DH). GIS-based DH projects usually emphasize spatial analysis and cartographic capability (e.g., displaying the locations of people, events, or movements), however, GIS alone cannot easily integrate multimedia components (e.g., descriptive text, photographs, digital audio, and video) of DH projects. Multimedia mapping provides a unique approach to integrating geospatial information in digital map format and multimedia information, which is useful for DH integration into spatial analysis and visualization. As cartographic mapping and GIS evolve from a traditional desktop platform to the World Wide Web, it is of significance to design and develop a Web-based multimedia mapping approach that could carry out spatial analysis and incorporate multimedia components, which is greatly beneficial to the DH applications. Our objectives of the language documentation research project in Nepal were to (1) use geo-tagging equipment to collect audio and visual recordings of three types of socio-linguistic data: language attitudes and practices interviews, free-form narratives, and elicited vocabulary and grammatical paradigm sets, from representative speakers of the four endangered languages in twenty-six Manang villages; (2) design and develop a Web-based, interactive multimedia atlas that can display data points corresponding to the speakers, links to the three types of data gathered in multimedia format, provides friendly user interface for the manipulation and spatial analysis of all the data. It is anticipated that the Web-based, interactive, and multimedia language atlas can bring all local and international stakeholders, such as the speech communities, linguists, local government agencies, and the public, together to raise awareness of language structures, language practices, language endangerment, and opportunities for preservation, all through this easy-to-use means that enhance the geo-spatial representation in engaging visual and sensory (multimedia) formats. Google Maps API and JavaScript are employed to develop this online, interactive, and multimedia language atlas.

Evaluating functions of reservoirs′ storage capacities and locations on daily peak attenuation for Ganjiang River Basin using Xinanjiang model

Flooding is the most prevalent and costly natural disaster in the world and building reservoirs is one of the major structural measures for flood control and management. In this paper, a framework was proposed to evaluate functions of reservoirs′ locations and magnitudes on daily peak flow attenuation for a large basin of China, namely Ganjiang River Basin. In this study, the Xinanjiang model was adopted to simulate inflows of the reservoirs and flood hydrographs of all sub-catchments of the basin, and simple reservoir operation rules were established for calculating outflows of the reservoirs. Four reservoirs scenarios were established to analyze reservoirs′ locations on daily peak flow attenuation. The results showed that: 1) reservoirs attenuated the peak discharges for all simulated floods, when the flood storage capacities increase as new reservoirs were built, the peak discharge attenuation by reservoirs showed an increasing tendency both in absolute and relative measures; 2) reservoirs attenuated more peak discharge relatively for small floods than for large ones; 3) reservoirs reduced the peak discharge more efficiently for the floods with single peak or multi peaks with main peak occurred first; and 4) effect of upstream reservoirs on peak attenuation decreased from upper reaches to lower reaches; upstream and midstream reservoirs played important roles in decreasing peak discharge both at middle and lower reaches, and downstream reservoirs had less effect on large peak discharge attenuation at outlet of the basin. The proposed framework of evaluating functions of multiple reservoirs′ storage capacities and locations on peak attenuation is valuable for flood control planning and management at basin scale.