WFS — Web Feature Service

The WFS (Web Feature Service) allows you to retrieve raw geographic features from GeoServer layers. Use WFS to download features as GeoJSON, filter by spatial or attribute criteria, and integrate feature data into your applications.

All requests go to: https://graph.quarticle.ro/graph/layers/wfs/

Authentication: Add the Authorization: YOUR_API_KEY header to all requests.

---

GetFeature

Retrieve geographic features from a WFS layer.

Required Parameters

Parameter	Description	Example
service	WFS	WFS
version	WFS version	2.0.0
request	GetFeature	GetFeature
typeNames	Layer name(s)	GRAPHRASTER:light_pollution

Optional Parameters

Filtering

Parameter	Description	Example
featureID	Return only features with specific ID	namespace:layername.id
bbox	Spatial filter: minx,miny,maxx,maxy,SRS	2554219.59,5763351.78,2554220.89,5763352.09,EPSG:3857
cql_filter	GeoServer CQL filter expression	population > 1000000
filter	OGC Filter XML	(see examples below)

Output Control

Parameter	Description	Example
outputFormat	Response format	application/json (GeoJSON)
srsName	Output coordinate system	EPSG:4326
propertyName	Comma-separated properties to return	name,population,area

Pagination

Parameter	Description	Example
count (WFS 2.0.0)	Max features to return	100
maxFeatures (WFS 1.1.0)	Max features to return	100
startIndex	Pagination offset	200

Sorting

Parameter	Description	Example
sortBy	Sort results by field	population D (descending) or population A (ascending)

---

Examples

Basic Feature Query

cURL

curl -X GET "https://graph.quarticle.ro/graph/layers/wfs/GetFeature" \
  -H "Authorization: YOUR_API_KEY" \
  --data-urlencode "service=WFS" \
  --data-urlencode "version=2.0.0" \
  --data-urlencode "request=GetFeature" \
  --data-urlencode "typeNames=GRAPHRASTER:light_pollution" \
  --data-urlencode "outputFormat=application/json"

JavaScript

const apiKey = process.env.QARTA_API_KEY;

const params = new URLSearchParams({
  service: 'WFS',
  version: '2.0.0',
  request: 'GetFeature',
  typeNames: 'GRAPHRASTER:light_pollution',
  outputFormat: 'application/json'
});

fetch(`https://graph.quarticle.ro/graph/layers/wfs/GetFeature?${params}`, {
  headers: { 'Authorization': `${apiKey}` }
})
  .then(r => r.json())
  .then(geojson => {
    console.log(`Retrieved ${geojson.features.length} features`);
    geojson.features.forEach(f => {
      console.log(f.properties);
    });
  });

Python

import requests
import json

api_key = os.getenv('QARTA_API_KEY')

response = requests.get(
  'https://graph.quarticle.ro/graph/layers/wfs/GetFeature',
  params={
    'service': 'WFS',
    'version': '2.0.0',
    'request': 'GetFeature',
    'typeNames': 'GRAPHRASTER:light_pollution',
    'outputFormat': 'application/json'
  },
  headers={'Authorization': f'{api_key}'}
)

geojson = response.json()
print(f'Retrieved {len(geojson["features"])} features')

---

Spatial Filter (BBox)

Query features within a bounding box:

cURL

curl -X GET "https://graph.quarticle.ro/graph/layers/wfs/GetFeature" \
  -H "Authorization: YOUR_API_KEY" \
  --data-urlencode "service=WFS" \
  --data-urlencode "version=2.0.0" \
  --data-urlencode "request=GetFeature" \
  --data-urlencode "typeNames=GRAPHRASTER:cities" \
  --data-urlencode "bbox=-74.1,40.6,-73.9,40.8,EPSG:4326" \
  --data-urlencode "outputFormat=application/json"

---

CQL Filter (Attribute Query)

Filter features by attributes using CQL (Common Query Language):

Simple Filter

# Get cities with population > 1 million
cql_filter=population > 1000000

Combined Conditions

# Urban areas with population > 500k
cql_filter=type = 'urban' AND population > 500000

Spatial CQL

# Features within a specific point (buffer)
cql_filter=DWITHIN(geom, POINT(-74.0060 40.7128), 1000, meters)

# Features containing a point
cql_filter=CONTAINS(geom, POINT(-74.0060 40.7128))

# Features intersecting a polygon
cql_filter=INTERSECTS(geom, POLYGON((-74.1 40.6, -73.9 40.6, -73.9 40.8, -74.1 40.8, -74.1 40.6)))

cURL Example

curl -X GET "https://graph.quarticle.ro/graph/layers/wfs/GetFeature" \
  -H "Authorization: YOUR_API_KEY" \
  --data-urlencode "service=WFS" \
  --data-urlencode "version=2.0.0" \
  --data-urlencode "request=GetFeature" \
  --data-urlencode "typeNames=GRAPHRASTER:cities" \
  --data-urlencode "cql_filter=population > 1000000 AND country = 'USA'" \
  --data-urlencode "outputFormat=application/json"

---

Property Selection & Pagination

Retrieve specific properties and paginate through large result sets:

cURL

curl -X GET "https://graph.quarticle.ro/graph/layers/wfs/GetFeature" \
  -H "Authorization: YOUR_API_KEY" \
  --data-urlencode "service=WFS" \
  --data-urlencode "version=2.0.0" \
  --data-urlencode "request=GetFeature" \
  --data-urlencode "typeNames=GRAPHRASTER:cities" \
  --data-urlencode "propertyName=name,population,country" \
  --data-urlencode "count=100" \
  --data-urlencode "startIndex=0" \
  --data-urlencode "sortBy=population D" \
  --data-urlencode "outputFormat=application/json"

JavaScript

async function getAllFeatures(typeName) {
  const apiKey = process.env.QARTA_API_KEY;
  const pageSize = 100;
  let allFeatures = [];
  let page = 0;

  while (true) {
    const params = new URLSearchParams({
      service: 'WFS',
      version: '2.0.0',
      request: 'GetFeature',
      typeNames: typeName,
      count: pageSize.toString(),
      startIndex: (page * pageSize).toString(),
      outputFormat: 'application/json'
    });

    const response = await fetch(
      `https://graph.quarticle.ro/graph/layers/wfs/GetFeature?${params}`,
      { headers: { 'Authorization': `${apiKey}` } }
    );

    const geojson = await response.json();
    allFeatures.push(...geojson.features);

    // Stop if fewer features than page size
    if (geojson.features.length < pageSize) break;
    page++;
  }

  return allFeatures;
}

---

Output Formats

WFS can return features in multiple formats:

Format	MIME Type	Use Case
GeoJSON	application/json	Recommended for web apps
GML 3	text/xml or application/gml+xml	OGC standard, GIS desktop apps
CSV	text/csv	Data analysis, Excel export

Example:

outputFormat=application/json    # GeoJSON
outputFormat=application/gml+xml # GML
outputFormat=text/csv            # CSV

---

Response Structure (GeoJSON)

A typical WFS response in GeoJSON format:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "id": "cities.1",
      "geometry": {
        "type": "Point",
        "coordinates": [-74.0060, 40.7128]
      },
      "properties": {
        "name": "New York",
        "population": 8335897,
        "country": "USA"
      }
    },
    {
      "type": "Feature",
      "id": "cities.2",
      "geometry": {
        "type": "Point",
        "coordinates": [-87.6298, 41.8857]
      },
      "properties": {
        "name": "Chicago",
        "population": 2693976,
        "country": "USA"
      }
    }
  ]
}

---

Error Handling

If a GetFeature request fails, the error is returned as XML by default:

<?xml version="1.0" encoding="UTF-8"?>
<ExceptionReport version="2.0.0">
  <Exception exceptionCode="InvalidParameterValue">
    <ExceptionText>
      Unknown typename: invalid_layer
    </ExceptionText>
  </Exception>
</ExceptionReport>

Or as JSON if you add &outputFormat=application/json:

{
  "code": "InvalidParameterValue",
  "message": "Unknown typename: invalid_layer"
}

Common errors:

• InvalidParameterValue: Wrong typeNames, srsName, or outputFormat
• NoApplicableCode: CQL filter syntax error or invalid property name
• Unauthorized: API key is missing or invalid
• ServiceException: General GeoServer error (check parameters)

---

Tips & Best Practices

1. Use JSON for web apps: outputFormat=application/json is easiest to parse in JavaScript
2. Filter early: Use bbox or cql_filter to reduce payload instead of downloading all features
3. Select properties: Only request the fields you need with propertyName=field1,field2
4. Paginate large sets: Use count and startIndex to avoid timeouts
5. Coordinate system: Data in EPSG:4326 (lat/lon) is standard; use srsName to transform if needed
6. Cache results: For frequently-accessed datasets, consider caching feature data locally

---

Next Steps

• GeoServer Overview
• WMS Guide — Render map tiles
• Feature Querying Use Case — Real-world feature query examples