Vector Graphics-Based Geospatial Contour Maps: A Web-Native Interactive Approach for Modern Geospatial Data Science Applications

Visualizing scalar fields (e.g., temperature, precipitation etc.) on the web is often done via pre‑rendered raster tiles. While simple to serve and fast to access, rasters limit interactivity (feature picking, dynamic styling) and typically require heavy pre‑generation pipelines. Raster tiles remain the dominant method for web-based scalar field visualization, but they are storage-heavy and inflexible, often requiring thousands of pre-generated images and limiting dynamic exploration. We present a lightweight method to render fully interactive, vector‑based contour maps for gridded scalar data in standard web mapping stacks. The approach computes isolines/isobands on demand from gridded fields, converts the contours to GeoJSON, and renders them as interactive vector layers without any pre‑tiled rasters. This enables hover/click inspection, dynamic filtering, level toggling, and restyling entirely client‑side. For large scenes, the same GeoJSON can optionally be streamed as vector tiles, but this is not required. Our method is particularly advantageous for environmental modeling workflows, where large gridded outputs from atmospheric transport or climate simulations must be explored interactively. By eliminating pre-rendered rasters and enabling dynamic contour generation, our method supports rapid, web-native visualization of model outputs such as pollutant dispersion or climate variables, improving interpretability and reducing operational overhead.