ProEssentials WPF NEXRAD Radar Reflectivity — 2D Contour Chart

A ProEssentials v10 WPF .NET 8 demonstration of real NEXRAD WSR-88D Level II radar data displayed as a 2D contour chart using the official NWS standard reflectivity color table. Real weather radar data from KFWS (Dallas/Fort Worth), March 4, 2025.

➡️ gigasoft.com/examples/120

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Quick Start — Just Run It

The pre-generated .bin file is included. Clone, build, run:

1. Clone this repository
2. Open NexradRadar.sln in Visual Studio 2022
3. Build → Rebuild Solution
4. Press F5

No Python required to display the radar chart.

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Data Pipeline

The .bin file was generated from real NOAA public radar data using a two-step pipeline. The raw V06 file and all pipeline tools are included so you can generate your own data from any NOAA radar station.

KFWS20250304_110319_V06          ← Raw NEXRAD L2 V06 (NOAA public data, 17MB)
        │
        ▼  (choose one)
┌─────────────────────┐    ┌──────────────────────────────────────┐
│  Python Pipeline    │    │  C# Converter (no Python needed)     │
│  step2_extract.py   │    │  NexradConverter/NexradConverter.cs  │
│  step3_cartesian_   │    │  Uses SharpCompress for BZ2          │
│    bin.py           │    │  dotnet run -- V06file output.bin    │
└──────────┬──────────┘    └──────────────────┬───────────────────┘
           │                                   │
           └──────────────┬────────────────────┘
                          ▼
              sweep_ref_800x450.bin
              800×450 float32 little-endian
              ~1 km/pixel, dBZ values
                          │
                          ▼
              NexradRadar WPF Chart

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Python Pipeline

Requires: numpy, scipy (standard scientific Python stack)

# Step 2: parse NEXRAD V06 → polar array
python step2_extract.py

# Step 3: polar → 800×450 Cartesian grid → .bin
python step3_cartesian_bin.py

step2_extract.py saves sweep_polar.npz (intermediate). step3_cartesian_bin.py reads sweep_polar.npz and writes sweep_ref_800x450.bin.

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C# Converter (Pure C#, No Python)

cd NexradConverter
dotnet run -- ../KFWS20250304_110319_V06 ../sweep_ref_800x450.bin

Uses SharpCompress NuGet for BZ2 decompression. Produces identical output to the Python pipeline.

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Downloading Your Own NEXRAD Data

NOAA provides free public access to all WSR-88D Level II archives:

AWS S3 (recommended — fastest):

s3://noaa-nexrad-level2/YYYY/MM/DD/KXXX/KXXXYYYYMMDDhhmmss_V06

NOAA NCEI:

https://www.ncei.noaa.gov/access/severe-weather/radar

Replace KFWS with any WSR-88D station ID (e.g. KORD Chicago, KLAX Los Angeles, KATL Atlanta). The V06 format is identical across all stations.

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Binary File Format

sweep_ref_800x450.bin
─────────────────────
Size    : 1,440,000 bytes (800 × 450 × 4 bytes)
Layout  : 800×450 IEEE 754 float32, little-endian, row-major
Row 0   : south edge,  Row 449 : north edge
Col 0   : west edge,   Col 799 : east edge
Values  : dBZ reflectivity, range approximately -10 to 76
NaN     : 0x7FC00000 — no radar data at this pixel (~1 km/pixel)

C# reading:

float[] data = new float[800 * 450];
using var br = new BinaryReader(File.OpenRead("sweep_ref_800x450.bin"));
for (int i = 0; i < data.Length; i++) data[i] = br.ReadSingle();
// data[row * 800 + col] = dBZ at pixel (col, row)

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NWS Standard Color Table

43 color bands from -10 to 76 dBZ — the classic TV weather radar look. Implemented via SubsetColors anchor interpolation (not a preset):

dBZ	Color	Meaning
< 0	Near black / gray	Noise floor
5	Bright cyan	Very light precipitation
10–15	Blue	Light rain
20–30	Green	Moderate to heavy rain
35	Bright yellow	Very heavy rain
45	Orange	Intense rain
50	Bright red	Severe
60	Magenta	Extreme
65	Purple	Extreme
76	White	Maximum

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ProEssentials Features Demonstrated

NullDataValueZ — pixels equal to the null sentinel render transparent, allowing the geographic map background to show through where there is no radar coverage.

SubsetColors anchor interpolation — custom color table defined by 18 anchor points linearly interpolated across 43 bands. More flexible than any built-in preset — use the same technique to implement any published color standard.

GraphBmpFilename + BitBltZooming — geographic map background that scales with zoom without dithering. The high-resolution PNG (4.7MB) maintains quality at any zoom level.

GraphBmpOpacity — radar overlay blended at 70% opacity over the map.

ManualScaleControlZ — locks the contour color scale to a fixed dBZ range regardless of the actual data range, ensuring consistent colors across different radar files.

CursorValueZ — returns the interpolated dBZ value at the exact mouse position — used for the live tooltip readout.

PeCustomTrackingDataText — custom tooltip formatting showing X km, Y km, and Z dBZ at the cursor.

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Controls

Input	Action
Left-click drag	Zoom box
Middle-click drag	Pan
Mouse wheel	Zoom in/out
Hover	Live dBZ readout in title bar and tooltip
Right-click	Context menu — export, print

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Prerequisites

• Visual Studio 2022
• .NET 8 SDK
• Internet connection for NuGet restore
• Python 3 + numpy (only if regenerating the .bin from raw data)

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NuGet Package

References ProEssentials.Chart.Net80.x64.Wpf. Restore is automatic on build.

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Related Examples

• Heatmap Spectrogram — Static
• Heatmap Spectrogram — Realtime
• WPF Quickstart
• All Examples — GigasoftInc on GitHub
• Full Evaluation Download
• gigasoft.com

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Data Credit

Radar data courtesy of NOAA National Weather Service. NEXRAD WSR-88D Level II data is free and publicly available from NOAA NCEI and AWS Open Data.

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License

Example code is MIT licensed. ProEssentials requires a commercial license for continued use. NEXRAD data is public domain (NOAA).