The IEM produces a number of RASTER images meant for GIS use. These RASTERs are typically provided on the IEM website as 8 bit PNG images. This means there are 256 slots available for a binned value to be placed. This page attempts to document these RASTER images and provide the lookup table of PNG index to an actual value. Click on the item in the "Label" column to get the lookup table below.
| Label | Description | Units |
|---|---|---|
| composite_eet | This is a composite of 8bit Echo Tops (EET) | kft |
| composite_n0q | This is a composite of 8bit Reflectivity (N0Q) | dBZ |
| composite_n0r | This is a composite of Reflectivity (N0R) | dBZ |
| mrms_a2m | NCEP MRMS 2 minute interval precipitation accumulation. | mm |
| mrms_lcref | NCEP MRMS 2 minute lowest elevation composite reflectivity. | dBZ |
| mrms_p1h | NCEP MRMS 1 Hour Accumulated Precipitation. | mm |
| mrms_p24h | NCEP MRMS 24 Hour Accumulated Precipitation. | mm |
| mrms_p48h | NCEP MRMS 48 Hour Accumulated Precipitation | mm |
| mrms_p72h | NCEP MRMS 72 Hour Accumulated Precipitation. | mm |
Programatic Access to this RASTER source
The IEM generated RASTERs are stored in a programatic way that should allow for easy scripted download of the archive. This section documents the URL format template used with the time shown in UTC. The string format modifiers below are pythonic strftime values.
https://mesonet.agron.iastate.edu/archive/data/%Y/%m/%d/GIS/uscomp/n0r_%Y%m%d%H%M.png
A general web service also exists to convert these RASTERs to netCDF "on-the-fly". The URL format is like so:
https://mesonet.agron.iastate.edu/cgi-bin/request/raster2netcdf.py?dstr=%Y%m%d%H%M&prod=composite_n0r
Try the netCDF Conversion!
Lookup Table for composite_n0r
| Color Index | Value (dBZ) | Red | Green | Blue | HEX |
|---|---|---|---|---|---|
| 0 | Missing | 0 | 0 | 0 | #000000 |
| 1 | -30 | 0 | 0 | 0 | #000000 |
| 2 | -25 | 0 | 0 | 0 | #000000 |
| 3 | -20 | 0 | 0 | 0 | #000000 |
| 4 | -15 | 0 | 0 | 0 | #000000 |
| 5 | -10 | 0 | 0 | 0 | #000000 |
| 6 | -5 | 0 | 0 | 0 | #000000 |
| 7 | 0 | 0 | 236 | 236 | #00ecec |
| 8 | 5 | 1 | 160 | 246 | #01a0f6 |
| 9 | 10 | 0 | 0 | 246 | #0000f6 |
| 10 | 15 | 0 | 255 | 0 | #00ff00 |
| 11 | 20 | 0 | 200 | 0 | #00c800 |
| 12 | 25 | 0 | 144 | 0 | #009000 |
| 13 | 30 | 255 | 255 | 0 | #ffff00 |
| 14 | 35 | 231 | 192 | 0 | #e7c000 |
| 15 | 40 | 255 | 144 | 0 | #ff9000 |
| 16 | 45 | 255 | 0 | 0 | #ff0000 |
| 17 | 50 | 214 | 0 | 0 | #d60000 |
| 18 | 55 | 192 | 0 | 0 | #c00000 |
| 19 | 60 | 255 | 0 | 255 | #ff00ff |
| 20 | 65 | 153 | 85 | 201 | #9955c9 |
| 21 | 70 | 255 | 255 | 255 | #ffffff |