Miscellaneous#

Get resource data#

Geodatata can be fetched for vector and raster layers. For vector layers (PostGIS and Vector) geodata returns in GeoJSON or CSV formats. For raster layers (Raster, WMS) - tiles (TMS) or image. For QGIS styles - qml file.

Export vector layer as file#

The following request returns GPKG, GeoJSON or CSV file from vector layer:

GET /api/resource/(int: id)/export?format=GPKG&srs=4326&zipped=True&fid=ngw_id&encoding=UTF-8#

Example request: https://sandbox.nextgis.com/api/resource/4308/export?format=GPKG&srs=4326&zipped=False&fid=ngw_id&encoding=UTF-8

Format string is case-sensitive. For formats and options list see https://docs.nextgis.ru/docs_ngcom/source/data_export.html

GeoJSON#

The following request returns GeoJSON file from vector layer:

Added in version 3.0.

GET /api/resource/(int: id)/geojson#

GeoJSON file request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Parameters:

id – resource identifier

Status Codes:

200 OK – no error

Example request:

GET /api/resource/55/geojson HTTP/1.1
Host: ngw_url
Accept: */*

CSV#

The following request returns CSV file from vector layer:

Added in version 3.0.

GET /api/resource/(int: id)/csv#

CSV file request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Parameters:

id – resource identifier

Status Codes:

200 OK – no error

Example request:

GET /api/resource/55/csv HTTP/1.1
Host: ngw_url
Accept: */*

Render#

The following request returns TMS from raster layer:

Added in version 3.0.

GET /api/component/render/tile?z=(int: z)&x=(int: x)&y=(int: y)&resource=(int: id1),(int: id2)...#

Tile request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Query Parameters:

id2 (id1,) – style resources id’s
z – zoom level
x – tile number on x axis (horizontal)
y – tile number on y axis (vertical)
cache – optional parameter (defaults true). If value set false tile will render from scratch
nd – Return code if tile not present. Available values are: 204, 404, 200. Defaults to 200.

Status Codes:

200 OK – no error
204 No Content – no tile
404 Not Found – no tile

The following request returns image from raster layer:

Added in version 3.0.

GET /api/component/render/image?extent=(float: minx),(float: miny),(float: maxx),(float: maxy)&size=(int: width),(int: height)&resource=(int: id1),(int: id2)...#

Image request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Query Parameters:

id2 (id1,) – style resources id’s
maxy (minx, miny, maxx,) – image spatial extent
height (width,) – output image size
cache – optional parameter (defaults true). If value set false tile will render from scratch

Status Codes:

200 OK – no error

Note

Styles order should be from lower to upper.

Example request:

GET /api/component/render/tile?z=7&x=84&y=42&resource=234 HTTP/1.1
Host: ngw_url
Accept: */*

QML Style (QGIS Layer style)#

The following request returns QML from QGIS style:

Added in version 3.0.1.

GET /api/resource/(int: id)/qml#

QML file request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Parameters:

id – resource identifier

Status Codes:

200 OK – no error

Example request:

GET /api/resource/56/qml HTTP/1.1
Host: ngw_url
Accept: */*

MVT (vector tiles)#

MVT data can be fetched only for NextGIS Web vector layer.

The following request returns MVT data:

Added in version 3.0.4.

GET /api/component/feature_layer/mvt?x=(int: x)&y=(int: y)&z=(int: z)&resource=(int: id1),(int: id2)...&simplification=(int: s)#

Vector tile request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Query Parameters:

id2 (id1,) – Vector or PostGIS layers identifies
z – zoom level
x – tile number on x axis (horizontal)
y – tile number on y axis (vertical)
s – simplification level (0 - no simplification, 8 - default value)

Status Codes:

200 OK – no error

Note

Vector or PostGIS layers identifies order should be from lower to upper.

Layers names in MVT will be ngw:(int:id), where id is vector or PostGIS layer identifier.

Example request:

GET /api/component/feature_layer/mvt?resource=56&z=11&x=1234&y=543 HTTP/1.1
Host: ngw_url
Accept: */*

Deprecated since version 3.0.4.

GET /api/resource/(int: id)/(int: z)/(int: x)/(int: y).mvt#

MVT request

Deprecated:

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Parameters:

id – resource identifier
z – zoom level
x – x tile column
y – y tile row

Status Codes:

200 OK – no error

Example request:

GET /api/resource/56/11/1234/543.mvt HTTP/1.1
Host: ngw_url
Accept: */*

Identify by polygon#

To get features intersected by a polygon execute following request.

POST /api/feature_layer/identify#

Identification request

Request Headers:

Accept – must be */*
Authorization – optional Basic auth string to authenticate

Request JSON Object:

srs (int) – Spatial reference identifier
geom (string) – Polygon in WKT format

Request JSON Array of Objects:

layers (int) – layers id array

Status Codes:

200 OK – no error

Example request:

POST /api/feature_layer/identify HTTP/1.1
Host: ngw_url
Accept: */*

{
    "srs":3857,
    "geom":"POLYGON((4188625.8318882 7511123.3382522,4188683.1596594 7511123.
                     3382522,4188683.1596594 7511180.6660234,4188625.8318882
                     7511180.6660234,4188625.8318882 7511123.3382522))",
    "layers":[2,5]
}

Example response:

{
  "2": {
    "featureCount": 1,
    "features": [
      {
        "fields": {
          "Id": 25,
          "name": "Church 1514-1925"
        },
        "id": 3,
        "label": "#3",
        "layerId": 2
      }
    ]
  },
  "5": {
    "featureCount": 0,
    "features": []
  },
  "featureCount": 1
}