Introduction
Maps convey direct information about the location, name, shape, and size of objects, as well as providing indirect information about spatial relationships among these objects. When a person needs to perform a map related task (e.g. finding geographic phenomena, route selection, navigation, distance estimation), he tends to memorize the relevant information on a (piece of) a map. Besides human (perceptual, cognitive, and visual) abilities, the retrieval of a spatial information is strongly correlated with map learning. Map learning distinguished from other learning concepts in a way that; (1) it requires comprehending and memorizing the direct information presented in maps and (2) all the information to be learned is presented at once. These two characteristics of map learning allow map users a flexibility of when, how and which order they execute a task such as selecting and focusing \citep*{Thorndyke_1980}. Hence, each user/user group develop different strategies of approaching the spatial information on maps.
This paper intends to examine map users’ cognitive processes of learning, acquiring and remembering the information presented via screen maps. Map users mentioned in the paper are broadly categorized as novices and experts considering their individual group differences of age, gender, ethnicity and language. The main research questions are addressed in this paper is “do the methods/approaches/strategies applied during map study and use (recall information) processes differ for novices and experts?”. In this context, the experiments were designed based on the principles and strategies defined by \citealp*{Thorndyke_1980}; \citealp{MONTELLO_1994}; \citealp*{p.2015}. Various methods (e.g. think-aloud, eye tracking, interview, etc.) have been applied to test the recall of map-related information from memory related to cognitive cartographic methods. Sketch maps are considered as one of the usability testing methods, since they represent the extracted information from a cognitive map (see equivalent terms; mental image, map image, mental map) through drawing \citep*{Tu_Huynh_2007}. This will be further discussed in the literature review in the following section.
User testing methods can be mixed for many reasons such as to enrich the quantitative research in cartography, to better contextualize map design and use/user recommendations, to improve the consistency and detail of results, to adopt and adapt new approaches to our study design and so on (\citealp{Roth_2017}). In our study, we also used mixed methods of sketch maps, eye tracking and post-test questionnaire. Both eye tracking and sketch map methods, individually, provided considerable amount of valuable information related to map users. Therefore, the combination of them may bring some advantages to user study design (in terms of methods and materials or user needs) and to evaluation of results, besides giving additional insights about map users’ behaviors.
Literature Review
Map Learning
Since this paper focuses on learning and remembering cartographic stimuli, it investigates how human cognitive system deals with geographic information presented via digital screen maps in order to produce cognitive maps. Especially in the last four decades, cognitive maps have become an intriguing research topic in geography (\citealp*{stea1977}); as well as in neuroscience (\citealp*{O_Keefe_1979}). Various researches in cartography directed an emphasis on how we "see" maps and how we derive meaning from them (\citealp{MacEachren}; \citealp{o2009}; \citealp{Ooms_2015}a). \citet*{Kulhavy_1996} stated that learning a map involves two interacting cognitive factors; (i) control processes and (ii) the memorial system. Control processes correspond to matching the map to the prior knowledge already exist in memory and how map-learning task should be achieved. In this respect, prior knowledge refers to both general and specific map knowledge. General map knowledge helps distinguishing maps from other spatial displays, and enables encoding of maps, and developing strategies for map learning. The influence of general map knowledge on map learning depends on perception of “maplikeness” and expertise (\citealp{Kulhavy_1993}a). In accordance to this interpretation, past researches show that map learning is more efficient when the stimulus is more maplike (\citealp{Kulhavy_1993}b; \citealp{Kulhavy_1983}) and that experts and novices differ little in terms of their ability to learn and remember information presented via maps (\citealp*{Thorndyke_1980} ; \citealp{Gilhooly_1988}). On the other hand, specific map knowledge stem from the modifications of related information in long-term memory (LTM) based on the degree of familiarity with particular map representations. These representations are called knowledge-weighted cognitive maps, which are constructed from perceptual stimulus, initial map-learning conditions and the way that the information has been used (\citealp*{Intons_Peterson_1991}).
The second cognitive factor of map learning - the memorial system - deals with the mode of representation (representational functions) and resources to store and maintain cognitive maps (computational functions)\citep*{Kulhavy_1996} . Since cognitive maps are the representations generated from visual stimulus (in other words, maps), it is important to remember the types of information that a map contains. A map image holds feature (i.e. visual variables (\citealp*{jacques1983}) and structural (spatial framework such as geometric and metric relations among features) information. While feature information answers “what is there?”, structural information defines the spatial characteristics of the space by addressing “where is it?”. To establish a link between maps and cognitive maps, we have to understand how our brain encodes spatial information when we learn a map. As \citet*{Kulhavy_1996} argues, whether our cognitive map just a collection of features and their properties is or does it encodes structural relationships, too? Since a map should contain both information, the question should be how similar the map and its cognitive map are.
In addition to representational functions, memorial system takes computational functions into account, because our cognitive system is capacity-limited in terms of encoding new information for storage in LTM and retrieving and make use of old information already in memory \citep*{Kulhavy_1996} . In order to understand how human brain store and recalls information, some definitions related to memory should be reviewed. As \citet*{Atkinson_1968} proposed, memory involves a sequence of three stages; sensory memory, working (short-term) memory, and LTM. Sensory memory holds the information gathered through all our senses (sensory registers) for a brief time span, then decays and is lost. A part of the information in the sensory memory is transferred to the working memory (WM). The WM can receive selected inputs from the sensory register as well as from LTM. WM is active during encoding and storing new information for short time periods or during the retrieval and use of old information. On the other hand, LTM retains the informative knowledge (memories, things we learn, etc.) permanently because it has an almost limitless capacity. Once the information held in the WM is transferred to LTM, it can be remembered for longer periods. This transmission is called learning process and requires rehearsal (\citealp*{Atkinson_1968} ; \citealp*{Kulhavy_1996} ; \citealp{Ooms_2015}a) (Figure 1). While LTM is known to have an unlimited capacity, WM has a limited capacity in terms of individual items of information processed. These individual pieces of information is called chunks. A chunk is any stimulus that has become familiar, hence recognizable, through experience (\citealp{1989}; \citealp{c.1998}). These chunks have to be transferred from LTM to WM to be able to draw cognitive maps.
Chunks of information from maps used to construct a mental map. Unlike employing mathematical formulas to express cartographic projections, there is no such language to translate our mental maps of the world. When reconstructing true sizes, shapes and positions of spatial elements from any cartographic projection, our minds reorganize the information entirely (\citealp{Tversky_1992}). Since we cannot yet formulate mental map construction precisely, it is not a straightforward job to assess and understand them without sufficient tools corresponding their complex nature.