Map Drawing Guide

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

Map Generation Endpoint

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

Required Parameters

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.

Time

Specify the timestamp for the data:

time=1766577600

Format: Unix timestamp

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)]

Style Parameters

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)

Fill Style

fill: How to fill the map

gradient - Smooth color gradient
band - Discrete color bands
none - No fill (contours only)

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

Contours

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

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)

Grid Numbers

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

Image Size

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

Saturation

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

Example Requests

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

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

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"

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.

Vector Data Format

For vector overlays (wind, currents), provide two fields separated by |:

Magnitude field: Speed or magnitude value
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.

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

Query Guide - Query syntax and expressions
API Examples - Example queries
Crystal - Frontend for viewing maps

ModMS

MAMS

Pinpoint

Legacy Met Tools

Geos

Geoterra

Map Drawing Guide

Map Generation Endpoint

Required Parameters

Fields

Time

Location

Style Parameters

Color Range

Fill Style

Colormap

Contours

Vectors

Grid Numbers

Image Size

Saturation

Example Requests

Temperature Map

Wind Vector Map

Precipitation with Contours

MAMS Query with Timestamp Format

Vector Data Format

Response Format

​Map Generation Endpoint

​Required Parameters

​Fields

​Time

​Location

​Style Parameters

​Color Range

​Fill Style

​Colormap

​Contours

​Vectors

​Grid Numbers

​Image Size

​Saturation

​Example Requests

​Temperature Map

​Wind Vector Map

​Precipitation with Contours

​MAMS Query with Timestamp Format

​Vector Data Format

​Response Format

​Related Documentation

Map Generation Endpoint

Required Parameters

Fields

Time

Location

Style Parameters

Color Range

Fill Style

Colormap

Contours

Vectors

Grid Numbers

Image Size

Saturation

Example Requests

Temperature Map

Wind Vector Map

Precipitation with Contours

MAMS Query with Timestamp Format

Vector Data Format

Response Format

Related Documentation