## 1 Introduction  
Since the creation of the first detailed geological map by [PERSON] in 1815, geological mapping has had a long history [1]. In conventional map-making, a toolbox including a pencil, a Brunton compass, a hammer, lenses, a notebook, and sketch paper is used to collect field geological data. Although conventional geological mapping is labor-intensive, geologists have worked in that way for a long time. In the digital era, new frameworks, instruments, and software packages, such as digital compasses, digital cameras, Geographic Information System (GIS) and Global Positioning System (GPS), have great potential to improve and even change the way of geological mapping. In recent decades, the approaches of digital geological mapping (DGM) have attracted increasing global attention. Many computer scientists and geologists have worked together to build a data framework of DGM and develop hard- and software systems to facilitate field geological survey and education [2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15]. Initiatives of DGM started in the 1980s. Due to the incomplete or ambiguous records by different geologists in the field at the data collection stage, some geological codes and principles were designed to standardize field data entry into a computer for producing digital geological maps and databases [16; 17]. Then, since the 1990s, field software systems of DGM have been developed, such as ArcPad-ArcGIS systems [5], GSMCAD FieldPad [18], MapIT [8; 10; 19], GeoMapper (PenMap) [3], FieldLog [20], FieldBook [21], Natmap [22], iGIS [23], the Digital Geological Survey System (DGSS) [24; 25; 26], and palmtop-based RDBMS and SIGMA systems [15], and tested for geological mapping in Europe, Australia, China,and North America. DGM development also led to discussions on the selection of hardware devices between Personal Digital Assistants (PDAs) and Tablet computers [9; 27]. In recent years, Android tablets and iPads have been widely popular, and some apps (e.g., FieldMove, StraboSpot, AoRGMAP, etc.) supporting field data collection have been developed and applied in geological mapping [28; 29; 30; 31]. DGM technology has not only changed the way of data collection and mapping in the industry but has also had a deep influence on the geological practice of undergraduates in the field [30; 31; 32; 33]. The DGSS developed by the Development and Research Center of China Geological Survey provides a pipelined solution for field data collection, data compilation, mapping, and data sharing in the industry based on a shared data flow. The DGSS includes the basic GIS platform DGSGIS, the desktop data processing system DGSIInfo for field data, a geodata adjustment system, and the field data collection system AoRGMAP in the handheld equipment [24; 25; 26]. DGSIInfo and DGSGIS are desktop software running on the Windows system (Win7 and later). AoRGMAP is a free app that can run on a PDA or smartphone with an Android system to collect field data. Although AoRGMAP can run on smartphones, there is a great accuracy difference between smartphones and customized PDA in terms of the digital compass and positioning system [33; 34]. A customized PDA is the preferred hardware for using AoRGMAP in industry application and field geological teaching. The DGSS has been used in the field of geological practice of undergraduates of China University of Geoscience (Wuhan) for a decade in Zhoukoudian, China [35; 36]. Although a lot of works about DGM and its application in geological education have been documented, most of them were reported in Chinese rather than in English, which made those latest works less visible to the global community. In this paper, based on the experiences in Zhoukoudian, China, we introduce the applications of the DGSS in the field geology practice of undergraduates in terms of field data collection, data integration and processing, and geological map production. The remainder of the paper is organized as follows. In Section 2, we introduce the geological setting and related background of this study.