The impact of Basemaps on Data Layers in a Web Map

Abstract

Web maps on the world wide web have experienced an increase in popularity the last decade. A vital component of any web map is the background layer acting as a reference layer for information presented on top. Although this reference layer referred to as basemap is a vital part of any web map, relatively little research has been done in examining how basemaps compare to each other and what makes some basemaps better suited for certain situations. This thesis examines the legibility of other information presented on top for three different basemaps.

Three basemaps used for web maps by ESRI are examined through a web experiment. A web application has been created to test the performance of each basemap. Nine tasks were created for the experiment, and a basemaps performance is measured through time elapsed to solve the given tasks. To achieve an acceptable degree of userfriendliness for the web application hosting the web experiment, pilot testing was conducted on the web application and results of the pilot test are presented in the thesis.

Two web experiments with a total of 360 participants has been conducted to test the performance of basemaps. The basemaps tested in this thesis are the topographic, world-imagery and dark-gray basemap. Comparisons between gender and level of experience were done on time elapsed for both experiments. Basemaps were also compared on time elapsed to solve the experiment for all participants, along with additional analyses where participants were divided into groups by gender and level of experience before comparisons were made.

Significant differences were found in both experiments, but for gender and level of experience between participants the differences were inconclusive. The first experiment concluded differences between genders existed, while the follow-up experiment concluded differences between experience existed. Differences between the three basemaps was found for male and non-experienced participants in the follow-up experiment, where the topographic basemap showed the longest time elapsed to complete the tasks. Hypotheses for how visual hierarchy, figure-ground separation and visual attention might have played a role in creating these results are presented, but further studies are needed to validate them. It was shown that differences exist between basemaps, and the dark-gray basemap worked consistently for most participants providing good results in both experiment.