NEXRAD Radar Visualization

NEXRAD Radar Visualization turns verified, decoded NEXRAD single-site products or radar mosaics into scientifically legible plots, holding a strict discipline that a visually compelling image must never hide a wrong quantity or a misleading spatial interpretation. It runs after nexrad-product-access or another trusted source has already decoded a site product, or after nexrad-mosaic-access has retrieved an official MRMS composite - it does not fetch or download radar files itself.

Before plotting anything it defines a visualization contract: site or domain, exact data level/product/moment, UTC observation time, the intended view type (PPI, RHI, cross-section, tilt, comparison, animation), sweep/angle policy, map projection and range rings, physical units and color scale, and how invalid/missing/folded/clutter-masked gates are treated. It validates the decoded site, product, time, units, and projection before rendering, applies scale/offset/calibration/quality flags before any interpolation or contouring, confirms a requested sweep actually exists, and preserves no-data cells as masked rather than substituting zero or a background color that looks like weak echo.

For a plan-position indicator it converts range/azimuth to the chosen map projection, masks invalid and clutter-contaminated gates by an explicit policy, and puts product, site, UTC time, units, sweep, range, and a color bar directly in the figure - keeping reflectivity's dBZ label visible rather than implying every color boundary is a categorical precipitation type, and using a diverging color scale centered on zero for radial velocity, which is explicitly labeled as radial (pointing toward or away from the radar) rather than a full wind vector. Dual-polarization moments keep their own physical units (differential reflectivity in dB, differential phase in degrees, correlation coefficient unitless), and any hydrometeor classification built from them states its input moments and whether it's measured, retrieved, or heuristic rather than being conflated with the raw fields.

When a sweep is chosen for a target height, it solves for the nearest sweep using the radar's elevation angles and a documented beam-height relationship, and explicitly labels the selected elevation and estimated sampling height rather than calling the lowest sweep a surface observation. RHI and cross-section views preserve source-volume identity and beam-height geometry, and never connect gates across large gaps or incompatible volumes without showing the gap. Time sequences use a verified chronological scan order, keep site/product/color-scale/bounds constant across frames, mark skipped or duplicated scans, and never silently duplicate a stale frame to fill a gap. For a precomputed mosaic like MRMS, it verifies product identity, valid time, grid projection, and coverage mask before rendering, preserves missing coverage as missing rather than zero, and keeps official provider products explicitly distinct from a locally constructed mosaic.

Before anything is handed off, the actual rendered file is inspected - not just the plotting call - for nonblank data, correct orientation, readable labels and color bar, undistorted aspect ratio, and no unintended missing-data substitution, with plotting-library versions, projection, and input identity recorded for reproducibility.

Use it to plot base reflectivity, radial velocity, spectrum width, or another decoded Level II moment for one site; a Level III product by code and scan time; a decoded MRMS or other documented gridded composite; a lowest- or specified-elevation PPI; dual-polarization moments; RHI, cross-section, tilt, or storm-relative views; a time-sequence animation; or an export with stable color scale and full metadata.

Do not use a plot to hide a missing sweep, an unverified product, an invalid gate mask, a geolocation error, or unsupported extrapolation. It does not fetch data, construct mosaics, or replace scientific interpretation.

Input is already-decoded NEXRAD site data or a decoded gridded mosaic, plus the requested view type and product. Output is the requested image, animation, or interactive view together with the exact site/domain, product/moment, UTC time, units, color range, missing-data policy, quality masks, projection, and processing transformations shown - never a plot without enough metadata for another analyst to know exactly what's displayed.

Consumes decoded data from nexrad-product-access and nexrad-mosaic-access, keeps a locally constructed mosaic's plotting distinct from nexrad-mosaic-construction's output, and pairs figures with weather-data-reproducibility when they must be regenerated later.

Atmospheric scientists and analysts producing radar plots for analysis or publication who need the figure itself to carry enough verified metadata - units, time, masking, geometry - that no one downstream can misread a masked gate as weak echo or a lowest sweep as ground truth.