Redraw the map: a web application for polygon schematization

In contrast to schematized line maps (mostly transit maps), schematized polygon maps are rarely used.One reason may be that creating them is tedious: even though computer scientists have been developing algorithms over the last two decades, none are currently ready for application by cartographers and map makers.These implementations are the result of algorithmic research and hence not necessarily intended to be easily accessible and ready to use.As a consequence, they require complex setups or are not robust enough for practical use.We thus lack a ready-to-use schematization tool.With this prototype for polygon schematization in the browser, we aim to fill the gap of accessible workflows.It is grounded in a defined set of functional requirements derived from cartographic best practices, including:• Support for importing and exporting geospatial data in common formats (e.g., GeoJSON, Shapefile, KML),• Automated validation of geometry type, topological consistency, coordinate reference system (CRS), and level of detail,• Interactive parameter adjustment to fine-tune the resulting schematization, and• Real-time feedback during the schematization process.The visual design of the interface builds upon these requirements, e.g. by adopting a layout with a central map canvas, a sidebar for parameter management, and contextual toolbars that appear based on user actions.The design emphasizes intuitive navigation (e.g. by using shortcuts) and progressive disclosure, i.e., revealing advanced options only when needed, which supports both novice and experienced users.Currently, creating schematized polygon maps is a time-consuming process requiring special knowledge, for both manual and automated creation:• Manual creation of schematized polygon maps in vector-editing software is time-consuming: e.g., it requires a complete redrawing when changing the projection or scale midway through the manual process.It also requires special knowledge: e.g., specific snapping tools depending on the used vector-editing software.• Automated generation is time-consuming, current implementations are hard to find (if they are publicly available).They also require special knowledge: e.g.setting up dedicated software environments.A web-based prototype, in turn, would be accessible to everyone, and is familiar to map-makers: tools like Mapshapermapshaper.org by Matthew Bloch, see Harrower and Bloch (2006)or geojson.io(by mapbox) are widely adopted.The implemented schematization algorithm is an area-preserving approach published by (Buchin et al., 2016).All edges of the resulting geometry are aligned to a set of orientations.This set is usually defined by cardinal (rectilinear) or intercardinal (octilinear) directions, but also allows arbitrary orientations (regularly and irregularly spaced).The algorithm consists of two steps: edge alignment and simplification.