Developing a GeoPackage Mobile App to Support Field Operations in Agriculture Chen Zhang, Ziheng Sun, Gil Heo, Liping Di*, Li Lin Center for Spatial Information Science and Systems George Mason University Fairfax, VA 22030, USA
[email protected], {zsun, gheo, *ldi}@gmu.edu,
[email protected] Abstract—GeoPackage, an open format for geospatial information, provides a gateway to bridge agricultural geographic information and mobile devices such as smartphones and tablets. In this paper, we present a Cordova framework based GeoPackage mobile application to support field operations in agriculture. By implementing GeoPackage SDK on mobile application, GeoPackage files can be easily accessed, managed, and visualized in field operation. Based on Cordova framework’s powerful extensibility, the application can be run on multiple mobile platforms such as iOS, Android, and Windows Phone to meet requirement of clients using different types of mobile operating system. Keywords—GeoPackage, Mobile application, Geospatial data, Field operation
I. INTRODUCTION With the rapid development of mobile devices in recent years, smartphones and tablets have became a new generation platform for geospatial data management and analysis. Although conventional desktop workstation is still the major tool in today’s GIS (Geographic Information System) field, the swift widespread of smartphone significantly accelerated the application of mobile geographic information system (mobile GIS), which defined as the integration of GIS, GPS (Global Position System), and RS (Remote Sensing) capability for accessing geospatial data using mobile devices [1]. Comparing with the traditional mobile devices, new generation of tablets and smartphones are equipped with powerful hardwares such as high performance center processing unit (CPU), mass storage memory, high resolution touching screen and camera, G-sensor, GPS module, fingerprint identification system. As the result of the advancement of the hardware, mobile operating system, such as iOS and Android, are developed as the next generation platform for data management and analysis based on its extraordinary portability and extensibility. According to the statistics of the mobile applications availability, more than 1.6 million apps are available for downloading in Google Play and more than 1.5 million apps are available for downloading in Apple’s App Store by July 2015, and this number keeps growing in exponent [2]. In modern agricultural activities, mobile device has became a indispensable tool for supporting field operation. The
advancement of GPS and its wide application made mobile device a useful tool for in situ collecting geospatial information [3]. Simultaneously, the performance gap between mobile devices and traditional desktop workstations has been narrowed due to the quick development of mobile chip market. For example, Apple A9 processor, the CPU of the latest iPhone series products, comes with dual cores of which the clocking speeds can be reached to 1.85 GHz. Qualcomm Snapdragon 820, an another mainstream processor towards to mobile platform and mainly used on Android devices, is powered by quad cores and its clocking speed can be up to incredible 2.2 GHz. Such powerful processors inside the smartphones make it possible to process and analyze data in real time. Therefore, based on the portability, functionality, and interoperability of mobile devices, users will be allowed to access, manage, analyze, visualize, and share many kinds of geospatial raster and vector data in agricultural field operations using smartphones or tablets anywhere and anytime. Imagine a small powerful tool which can be held in the pocket and carried to the field, such advantages will offer great benefits for millions of agricultrual related users including farmers, researchers, educators, students. As a new open format for transfering geospatial information, OGC (Open Geospatial Consortium) GeoPackage, which characterized by standards-based, platform-independent, portable, self-describing, and compact, provides a gateway to bridge agricultural geographic information and mobile devices [4]. Since pulished in 2014, GeoPackage has been widely implemented by many major vendors and open source packages including GDAL, Luciad, QGIS, Esri, NGA (National Geospatial-Intellegence Agency), GeoServer, and Safe Software. In this paper, we developed a Cordova framework based GeoPackage mobile application to support field operations in agriculture. By implementing NGA GeoPackage Library on mobile application, users can easily access, manage and visulize the GeoPackage files in filed operation. Besides, to meet the requirement of clients using different types of mobile devices, we adopt Apache Cordova as the mobile application development framework to wrap CSS, HTML, and JavaScript code. Based on the powerful extensibility of Cordova framework, the application can be run on multiple mobile plarforms including iOS, Android, and Windows Phone.
II. RELATED WORK Many mobile platform based projects and products are accelerating the agricultural production and facilitating the study in agriculture area. Different with the traditional desktop workstation, mobile devices provide a more flexible way to support agricultural field operation.
instead of platform-specific APIs. On the other hand, we adopt NGA GeoPackage JavaScript library, which provides GeoPackage functionality and utilities to node and web applications, as the major implementation library. The architecture of GeoPackage mobile application is displayed as Fig. 1.
In 2012, Delgado, Kowalski, and Tebbe proposed the first mobile application of the Nitrogen Index. The aim of this tool is helping farmers to implement better nitrogen management practice, increase nutrient use efficiencies at the field level, lower impacts to the environment from nitrogen losses, and achieve higher economic returns [5]. Geofairy, a multi platform mobile application operated by Center for Spatial Information Science and Systems (CSISS), George Mason Univeristy, was released to support field operation in agriculture in 2014 [5]. As a hub of geospatial informationto, Geofairy retrieves agricultural data from 8 source datasets with more than 100 data layers covering the whole globe and provides different types of agricutural information including weather, vegetation, elevation, soil moisture, land cover, atmosphere and precipitation. Lomotry, Chai, Jamal, and Deters initiated MobiCrop project [7] as a mobile distributed system with a three-layered deployment consists of mobile nodes, a cloud-hosted middleware, and a cloud-hosted database. MobiCrop application was desgined towards to iOS devices such as iPhone and iPad which enable farmers to have mobile access to make decisions on applying pesticedes. In 2015, Ferreira, Vinhas, Bogossian, de Carvalho [3] proposed TerraMobile App as an Android based mobile application for geographical data gathering and validation in fieldwork. As a case that implementing GeoPackage on mobile devices, in TerraMobile App, the offline geofraphical data are stored in OGC GeoPackage file. TerraMobile plugin was developed to access and generate GeoPackage files, and the file will be availbale through TerraMobile server. III. FRAMEWORK To implement OGC GeoPackage on mobile devices, we adopt NGA GeoPackage libraries which provides the ability to read, write, import, export, share, and manage GeoPackage files. NGA GeoPackage Libraries is a series of open source libraries including Java library, Android SDK, iOS SDK, and JavaScript library. As discussed in the section I, Android and iOS are two major platforms in today’s mobile market. To implement GeoPackage on Android and iOS based mobile devices, we can choose Android SDK or iOS SDK which providing GeoPackage functionalities and utilities to Android/iOS apps. However, using Android SDK on iOS SDK makes the project relying on platform-specific APIs, which means the process of developing Android project and the iOS project are mutually independent. To make the mobile application more flexible and easier to be implemented across different mobile platforms, we use Apache Cordova as the general framework for web-based hybrid mobile application, which allow developers build mobile applications using CSS3, HTML5, and JavaScript
Fig. 1. The architecture of GeoPackage mobile application The architecture of the project consists of several parts: the NGA GeoPackage JavaScript Library, Cordova Application, and Mobile OS. Cordova Application, as the core component of the architecture, consists of three major parts: Web App, HTML Rendering Engine (WebView), and Cordova Plugins. Among which, Web App interacts with NGA GeoPackage JavaScript Library via JS APIs, HTML Rendering Engine and Cordova Plugins interact with Mobile OS via iOS API, Android API, and other platform-specific APIs such as Windows Phone API, Firefox OS API, Ubuntu Touch API, Blackberry OS API, and LG webOS API. IV. EXPERIMENT As shown in the Fig. 2, NGA provides an official open source demo of the web application implementation of GeoPackage JavaScript Library [8]. The interface of the NGA GeoPackage JavaScript implementation demo consists of a OpenLayers Map and a control panel, users can open GeoPackage files from local disk or sample links then the data will be displayed on OpenLayers .
screenshot of the iOS app running on iPhone 6/iPhone 6s is shown in Fig. 3 (the layout of the app may vary when the resolution of the device has changed), we can see some GeoPacakge data is loaded by turning on the switch button in control panel on the right and displayed on the left. As the basemap, OpenStreetMap covers the whole world with up-todate geographic information data, in this case, three GeoPackage files “foul_sewer”, “a_manhole”, and “surface_water_sewer” are displayed on the basemap. To protect systems and user’s privacy, iOS limits the privileges of all apps by “App Sandboxing” and users cannot read GeoPackage files from any local path of local storage. Alternatively, as shown in the Fig. 4, iOS allows user open data from cloud drive such as iCloud Drive and OneDrive, which provides an alternative way for reading user’s GeoPacakge files. Fig. 2. The interface of NGA GeoPackage JS Demo
V. CONCLUSION In this paper, we present a Cordova framework based GeoPackage mobile application to support field operations in agriculture. By implementing GeoPackage SDK on mobile application, users can easily access, manage and visualize GeoPacakge files in field operation. Furthermore, the powerful extensibility of Cordova framework makes the app performing flexible on multiple mobile platforms including iOS, Android, and Windows Phone. Experiment result shows the mobile application implemented using our architecture provides an approach to accelerate the field operation and facilitate the study in agriculture area. ACKNOWLEDGMENT
Fig. 3. The interface of GeoPackage iOS app
This work is supported by OGC Testbed 12, and partially by grants from NSF EarthCube (Grant # ICER-1440294, PI: Dr. Liping Di) and the U.S. Department of Energy (Grant # DE-NA0001123, PI: Dr. Liping Di). REFERENCES [1]
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Fig. 4. Reading GeoPackage files from cloud drive [6]
Based on the architecture of the section III, we implemented a Cordova based mobile application on iOS mobile device using NGA GeoPackage JavaScript Demo. The
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