Chapter 6: APIs, Web Services & AI-Ready Data

Access data programmatically — query live government databases from your code.

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Why APIs?

Downloading files manually is fine for one-time analysis. But if you need the latest data automatically, or want to build an application that updates live, you need an API. This chapter shows you how.

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Prerequisites

Skills Required

This is the most technical chapter in the book. You should be comfortable with: - Basic Python (how to install packages, write functions) - HTTP requests (what a URL query parameter is) - JSON format (reading key-value pairs)

If not, Chapter 7: Visualizing Data covers enough Python to get started.

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What Are OGC Web Standards?

Before using geospatial web services, understand the OGC (Open Geospatial Consortium) standards — the international protocols that all major geospatial servers follow:

Standard	Full Name	Returns	Use Case
WMS	Web Map Service	PNG/JPEG image tiles	Background maps, visual layers
WFS	Web Feature Service	GeoJSON/GML vector data	Queryable spatial features
WMTS	Web Map Tile Service	Pre-rendered tiles	Fast background maps
WCS	Web Coverage Service	Raster grid data	Elevation, rainfall grids
CSW	Catalogue Service	Metadata	Finding available datasets

GetCapabilities URL: Every OGC service has a URL you can append ?SERVICE=WMS&REQUEST=GetCapabilities to see all available layers.

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Chapter Datasets

#	Dataset	Provider	Standard	Level
1	Bhuvan OGC Services	NRSC/ISRO	WMS/WFS	🔵
2	GEE Python API	Google	Python SDK	🔴
3	AI Kosh	CDAC/MeitY	REST API	🟡
4	data.gov.in API	MeitY	REST API	🔵
5	WRIS Web Services	CWC/NIH	WMS/WFS	🔵

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✏️ First API Exercise

Exercise 6.0 — Your First API Call

Goal: Fetch data from data.gov.in API and print it.

import requests
import json

# data.gov.in API — No key required for basic browsing
# Find datasets
url = "https://data.gov.in/api/datastore/resource.json"
params = {
    "resource_id": "6176ee09-3d56-4a3b-8115-21841576b2f6",  # Census district pop
    "limit": 5,
    "filters[State]": "Goa"
}

response = requests.get(url, params=params)

if response.status_code == 200:
    data = response.json()
    print(f"Total records: {data.get('total', 'unknown')}")
    print("\nFirst 5 records:")
    for record in data.get('records', []):
        print(json.dumps(record, indent=2))
else:
    print(f"Error: HTTP {response.status_code}")
    print("Note: Some resources require an API key — register at data.gov.in")

What you should see: Population data for Goa districts printed in JSON format.

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Start with: Bhuvan OGC Services →