MapUp: A Declarative Interface for the Leaflet Library

Interactive web maps are used in many domains, including logistics, tourism, and data journalism. The Leaflet library provides a flexible technical foundation for building such applications, but their use often requires JavaScript knowledge and an understanding of the underlying object model. Existing web mapping platforms reduce this complexity, but typically within a specific application environment. This raises the question of to what extent Leaflet-based web mapping functionality can be provided via a declarative interface without sacrificing it’s flexibility. To address this question we present MapUp, a work-in-progress approach that combines Leaflet with Web Components. MapUp provides reusable custom HTML elements for maps, tiles, markers, layer groups, and GeoJSON-based data. These components can be configured through attributes, declaratively nested, and connected via DOM events and public methods. The prototype shows how web mapping tasks can be expressed with less JavaScrip t while still allowing advanced users to access the Leaflet objects. We illustrate the approach through representative scenarios. The paper discusses the benefits and limitations and outlines future work on larger datasets, backend integration, and evaluation.