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ModMS can generate map images (PNG) from weather model data with customizable styling, colormaps, contours, and vector overlays.

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Map Generation Endpoint

Base URL: http://modms.devops.arabiaweather.com/q Format: Set format=png to generate a map image instead of JSON data.

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Required Parameters

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Fields

The fields parameter specifies what to plot. For vector data (wind), use | to separate magnitude and direction: 
fields=speed(GFS.ISO200HPA.UGRD, GFS.ISO200HPA.VGRD) | dir(GFS.ISO200HPA.UGRD, GFS.ISO200HPA.VGRD)
Format:
  • Scalar data: Single expression (e.g., GFS.GND2M.TMP-273.15)
  • Vector data: Two expressions separated by |:
    • First: Magnitude (e.g., speed(u, v))
    • Second: Direction (e.g., dir(u, v))
Model Run Specification:
  • ModMS: Can use MODEL.LEVEL.VARIABLE (latest) or MODEL@model-run.LEVEL.VARIABLE (e.g., GFS@2218)
  • MAMS: Must use MODEL@timestamp.LEVEL.VARIABLE (e.g., GFS@1766577600)
When querying MAMS, you must use timestamp format (MODEL@timestamp) instead of model-run format.

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Time

Specify the timestamp for the data: 
time=1766577600
Format: Unix timestamp

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Location

Specify the geographic bounding box and image size: 
location=[(lat1,lon1) to (lat2,lon2) size (width,height)]
Format:
  • Bounding box: (lat1,lon1) to (lat2,lon2) - Southwest to Northeast corners
  • Image size: size (width,height) - Output image dimensions in pixels
Example: 
location=[(40.9799,22.5) to (55.7766,45) size (512,512)]

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Style Parameters

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Color Range

min: Minimum value for color scale (default: 0) max: Maximum value for color scale (default: 100) step: Step size for color bands (default: 1)

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Fill Style

fill: How to fill the map
  • gradient - Smooth color gradient
  • band - Discrete color bands
  • none - No fill (contours only)

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Colormap

colormap: Color scheme name Available colormaps:
  • Standard: jet, hsv, magma, inferno, plasma, viridis, spectral
  • Diverging: rdylgn, rdbu, burd, piyg, prgn, rdylbu, brbg, rdgy, puor
  • Sequential: orrd, pubu, bupu, oranges, bugn, ylorbr, ylgn, reds, rdpu, greens, ylgnbu, purples, gnbu, greys, ylorrd, purd, blues
  • Custom: shaker1, shakerwind, shakercape, shakercape2
  • Meteorological: temp, temp2, temp3, wind, humid, cape, gph, prec, bprec, bprec2, clouds, thickness

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Contours

contour: Enable contour lines (true/false, default: false) linewidth: Contour line width (default: 1) contour_color: Contour line color (default: black)

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Vectors

vector: Vector overlay style
  • none - No vectors (default)
  • vector - Arrow vectors
  • barb - Wind barbs
  • direction - Direction only
vector_density: Number of vectors per grid (default: 40)

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Grid Numbers

numgrid: Show grid point values (true/false, default: false)

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Image Size

image_width: Output image width in pixels (default: auto-calculated) fontsize: Font size for labels (default: 0 = auto)

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Saturation

saturate_min: Saturate values below minimum (true/false, default: false) saturate_max: Saturate values above maximum (true/false, default: false)

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Example Requests

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Temperature Map

curl "http://modms.devops.arabiaweather.com/q?fields=GFS.GND2M.TMP-273.15&time=1766577600&location=[(40.9799,22.5)%20to%20(55.7766,45)%20size%20(512,512)]&format=png&min=-10&max=50&step=5&fill=gradient&colormap=burd&contour=false&vector=none"
Decoded: 
fields=GFS.GND2M.TMP-273.15
time=1766577600
location=[(40.9799,22.5) to (55.7766,45) size (512,512)]
format=png
min=-10
max=50
step=5
fill=gradient
colormap=burd
contour=false
vector=none

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Wind Vector Map

curl "http://modms.devops.arabiaweather.com/q?fields=speed(GFS.ISO200HPA.UGRD%2C%20GFS.ISO200HPA.VGRD)%20%7C%20dir(GFS.ISO200HPA.UGRD%2C%20GFS.ISO200HPA.VGRD)&time=1766577600&location=[(40.9799%2C22.5)%20to%20(55.7766%2C45)%20size%20(512%2C512)]&format=png&fontsize=14&min=0&max=100&step=1&fill=gradient&contour=false&vector=vector&colormap=shakerwind&numgrid=false&linewidth=2&saturate_min=false&saturate_max=false"
Decoded: 
fields=speed(GFS.ISO200HPA.UGRD, GFS.ISO200HPA.VGRD) | dir(GFS.ISO200HPA.UGRD, GFS.ISO200HPA.VGRD)
time=1766577600
location=[(40.9799,22.5) to (55.7766,45) size (512,512)]
format=png
fontsize=14
min=0
max=100
step=1
fill=gradient
contour=false
vector=vector
colormap=shakerwind
numgrid=false
linewidth=2
saturate_min=false
saturate_max=false

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Precipitation with Contours

curl "http://modms.devops.arabiaweather.com/q?fields=GFS.SFC.APCP.HR&time=1766577600&location=[(30,30)%20to%20(40,40)%20size%20(512,512)]&format=png&min=0&max=25&step=1&fill=gradient&contour=true&colormap=jet&linewidth=2"

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MAMS Query with Timestamp Format

When querying MAMS, use timestamp format for model runs: 
curl "http://mams.devops.arabiaweather.com:8081/q?fields=speed(GFS%401766577600.ISO200HPA.UGRD%2C%20GFS%401766577600.ISO200HPA.VGRD)%20%7C%20dir(GFS%401766577600.ISO200HPA.UGRD%2C%20GFS%401766577600.ISO200HPA.VGRD)&time=1766577600&location=[(40.9799%2C0)%20to%20(55.7766%2C22.5)%20size%20(512%2C512)]&format=png&fontsize=14&min=0&max=100&step=1&fill=gradient&contour=false&vector=vector&colormap=shakerwind&numgrid=false&linewidth=2&saturate_min=false&saturate_max=false&image_width=512"
Decoded: 
fields=speed(GFS@1766577600.ISO200HPA.UGRD, GFS@1766577600.ISO200HPA.VGRD) | dir(GFS@1766577600.ISO200HPA.UGRD, GFS@1766577600.ISO200HPA.VGRD)
time=1766577600
location=[(40.9799,0) to (55.7766,22.5) size (512,512)]
format=png
...
Notice the GFS@1766577600 format - MAMS requires Unix timestamp format, not model-run format like GFS@2218.
For information about Crystal layer definitions, see the Layer Definitions documentation.

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Vector Data Format

For vector overlays (wind, currents), provide two fields separated by |:
  1. Magnitude field: Speed or magnitude value
  2. Direction field: Direction in degrees
Example: 
fields=speed(GFS.GND10M.UGRD, GFS.GND10M.VGRD) | dir(GFS.GND10M.UGRD, GFS.GND10M.VGRD)
The magnitude determines vector length, direction determines orientation.

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Response Format

When format=png, the API returns a PNG image that can be:
  • Displayed directly in browsers
  • Saved to a file
  • Embedded in web pages or reports