Raster maps

Available services

Jāņa sēta offers five types of raster map layers in different projections:

  • coloured (traditional) Jāņa sēta map;
  • greyscale Jāņa sēta map;
  • cadastral information layer (Latvia only);
  • LĢIA topographic map (Latvia only);
  • LĢIA ortophoto map (Latvia only).

Raster maps can be included in your own products or added to desktop programs by using Jāņa sēta WMS or WMTS services. The services conform to the OGC online mapping standards and are compatible with web map libraries and desktop programs.

WMS

WMS service is used to request rectangular map fragments in freely chosen coordinates. WMS map fragment request base URL is created according to the following scheme:

https://wms<link_number>.kartes.lv/<client_key>/<projection_key>/<layer_key>/

Parameter Description Values
<link_number> Web map libraries (Leaflet, OpenLayers) can be provided with multiple domains, which can improve parallel loading speed of map fragments. If only one domain is used, then slower map loading is possible due to browser restrictions.
  • empty
  • 1
  • 2
  • 3
  • 4
<client_key> Your private Jāņa sēta services access key.
<projection_key> Projection key describes service's coordinate system (CRS).
  • wgs - Web mercator coordinate system (EPSG:3857);
  • lks - Latvian coordinate system, LKS-92 (EPSG:3059)
<layer_key> Layer key describes returned map layer. It should be noted that not all layers are available in all coordinate systems.
  • 15 - coloured (traditional) map;
  • 15bw - greyscale map;

  • Only wgs:
  • orto - latest Latvian ortophoto map (LĢIA);
  • topo - Latvian topographic map in scale 1:50 000 (LĢIA);
  • cadastral - Latvian cadastral information layer (cadastral unit borders and building contours) (VZD).

Each base URL describes a service for single map layer in single projection. This base URL must be added to map library or desktop program configuration. Further preparation of the raster map service and requesting of specific map fragments will be done automatically.

Service capabilities document

Services' coordinate systems, their extents, sublayers and other parameters can be acquired by making a GetCapabilities request. It returns a standardised XML document, which can be used to precisely setup map layers. Desktop programs use this document to automatically configure the service. In other cases, it is not necessary to request or read it.

GetCapabilities request URL is created according to the following scheme:

https://wms<link_number>.kartes.lv//<projection_key>/<layer_key>/?service=WMS&request=GetCapabilities&version=1.3.0

Parameter Description Values
service Service type.
  • WMS
request GetCapabilities request returns service description in XML format.
  • GetCapabilities
version Specifies used WMS standard version. For this document there are no significant changes between versions.
  • 1.0.0
  • 1.1.0
  • 1.1.1
  • 1.3.0

Map fragment images

To get the map fragment images themselves, a GetMap request must be made. The desired image width, height and geographical coordinates of the fragment's corners can be specified. Request URLs are created by adding the following GET parameters to the service's base URL:

Parameter Description Values
service Service type.
  • WMS
request GetMap request returns map fragment image.
  • GetMap
version Specifies used WMS standard version.
  • 1.0.0
  • 1.1.0
  • 1.1.1
  • 1.3.0
srs
crs (1.3.0)
Projection EPSG code. Must select a code corresponding to the projection in service's base URL. WGS:
  • EPSG:3857
LKS:
  • EPSG:3059
  • EPSG:25884
width Image width (pixels).
height Image height (pixels).
bbox Rectangular region of the map fragment. Must provide comma separated minimal and maximal x (longitude) and y (latitude) coordinates in the selected projection (srs or crs parameter). The x and y coordinates of the lower left corner should be specified first, then the upper right corner. xMin,yMin,xMax,yMax

Examples

Coloured Jāņa sēta map WMS capabilities document:

https://wms.kartes.lv//wgs/15/?SERVICE=WMS&VERSION=1.0.0&REQUEST=GetCapabilities

Coloured Jāņa sēta map WMS request in WGS projection:

https://wms.kartes.lv//wgs/15/?SERVICE=WMS&VERSION=1.0.0&REQUEST=GetMap&BBOX=2682999,7748141,2686161,7750701&SRS=EPSG:3857&WIDTH=420&HEIGHT=340

Coloured map fragment

Greyscale Jāņa sēta map WMS request in LKS projection

https://wms2.kartes.lv//lks/15bw/?SERVICE=WMS&VERSION=1.0.0&REQUEST=GetMap&BBOX=495210.2393944038195%2C297323.7185847196961%2C522621.1243179840385%2C316295.4527800377691&SRS=EPSG%3A3059&WIDTH=502&HEIGHT=348&FORMAT=image%2Fpng

Greyscale map fragment LKS

Cadastral map WMS request

https://wms1.kartes.lv//wgs/cadastral/?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&FORMAT=image%2Fpng&TRANSPARENT=true&WIDTH=256&HEIGHT=256&CRS=EPSG%3A4326&STYLES=&BBOX=2737057.1094378084%2C7756218.134887848%2C2738280.1018904033%2C7757441.127340443

Cadastral map fragment

LKS best resolution setup

To get the most detailed images map fragments must be requested in scales, which precisely match map zoom levels. In WGS projection (EPSG:3857), it is set up automatically, but in LKS projection (EPSG:3059) scale level resolutions must be configured manually in map libraries.

Scale level Resolution WGS Resolution LKS
0.
1. 78271.51696
2. 39135.75848
3. 19567.87924
4. 9783.939620
5. 4891.969810 6007.4787274574555
6. 2445.984905 3003.7393637287278
7. 1222.992452 1501.8695495724326
8. 611.4962263 750.93477478621628
9. 305.7481131 375.46751968503941
10. 152.8740566 187.73362755058844
11. 76.43702829 93.86694606722547
12. 38.21851414 46.933473033612735
13. 19.10925707 23.4667365168063
14. 9.554728536 11.733235966471934
15. 4.777314268 5.8666179832359671
16. 2.388657133 2.9334412835492341
17. 1.194328566 1.4665883498433665
18. 0.597164263 0.73342646685293378
19. 0.298582142 0.36671323342646689

If LKS projection is used with a tiled WMS, it is recommended to provide tile origin coordinates (x, y):
-5682840.1444699997, 4997050.3242600001

WMTS

WMTS service is used to request square map fragments (tiles) by providing tile zoom, row and column sequence numbers.

Service capabilities document

Services' coordinate systems, their extents, precise map tile placement and other parameters can be acquired by making a GetCapabilities request. It returns a standardised XML document, which can be used to precisely setup map layers. Desktop programs use this document to automatically configure the service. In other cases, it is not necessary to request or read it.

Service capabilities document can be obtained by requesting the following URL:

https://wms.kartes.lv//wgs/WMTS/?request=GetCapabilities

This URL must be added to map library or desktop program configuration. Further preparation of the raster map service and requesting of specific map fragments will be done automatically.

Map tile images

To get the map tile images themselves, a request must be made specifying the tile scale, column and row numbers. The request URL is created according to the following scheme:

https://wms<link_number>.kartes.lv/<client_key>/wgs/<layer_key>/<scale_number>/<column_number>/<row_number>.png

Parameter Description Values
Web map libraries (Leaflet, OpenLayers) can be provided with multiple domains, which can improve parallel loading speed of map fragments. If only one domain is used, then slower map loading is possible due to browser restrictions.
  • empty
  • 1
  • 2
  • 3
  • 4
Your private Jāņa sēta services access key.
Layer key describes returned map layer.
  • 15 - coloured (traditional) map;
  • 15bw - greyscale map;
  • orto - latest Latvian ortophoto map (LĢIA);
  • topo - Latvian topographic map in scale 1:50 000 (LĢIA);
  • cadastral - Latvian cadastral information layer (cadastral unit borders and building contours) (VZD).
Map tile scale number (z value).
Map tile column number (x value).
Map tile row number (y value).

WMTS service is available only in WGS—84 (EPSG:3857) projection according to Google Maps map tiling scheme. The tile request will return a 256 pixels by 256 pixels large PNG image. Scale, column and row numbers are counted starting from zero. There is a single tile on the zero scale level (0,0). It covers the entire world. At each subsequent scale level, the tiles are divided into four equal parts. Precise scales and coordinates for each zoom level can be found in the capabilities document. (GetCapabilities).

Examples

Coloured Jāņa sēta map tile:

https://wms.kartes.lv//wgs/15/12/2336/1251.png

Coloured map tile

Error codes

Code Description
400 Request parameters missing or incorrect.
404 Requested resource not found.
5xx Server error.

Examples of setup in map libraries

Leaflet

Below are two examples of raster map implementations in the Leaflet web map library:

  1. greyscale Jāņa sēta map WMS service;
  2. combined LĢIA ortophoto and cadastral WMTS services.

In both examples WGS projection is used and the map is initially centered in Riga.

const map = L.map('mapId', {
    layers: [
        L.tileLayer.wms('https://wms{s}.kartes.lv/<span class="kijs_key"></span>/wgs/15bw/', {
            subdomains: ['', '1', '2', '3', '4'],
            attribution: '<a href="https://balticmaps.eu" target="_blank">Jāņa sēta</a>',
        }),
    ],
    center: [56.96, 24.11],
    zoom: 12,
})
const map = L.map('mapId', {
    layers: [
        L.tileLayer('https://wms{s}.kartes.lv/<span class="kijs_key"></span>/wgs/orto/{z}/{x}/{y}', {
            subdomains: ['', '1', '2', '3', '4'],
            attribution: '<a href="https://balticmaps.eu" target="_blank">Jāņa sēta</a>, <a href="https://www.lgia.gov.lv/" target="_blank">LĢIA</a>',
        }),
        L.tileLayer('https://wms{s}.kartes.lv/<span class="kijs_key"></span>/wgs/cadastral/{z}/{x}/{y}', {
            subdomains: ['', '1', '2', '3', '4'],
            attribution: '<a href="https://www.vzd.gov.lv/" target="_blank">VZD</a>',
        }),
    ],
    center: [56.96, 24.11],
    zoom: 12,
})

OpenLayers

The following describes several examples of the implementation of Jāņa sēta services in the OpenLayers web library.

WMS service

In the first example, the coloured Jāņa sēta map layer is created. Also the general map object is created, the map gets centered in Riga and the previously created myLayer layer is added to it.

The layers created in other examples must be added to the map object as it is done in this example.

import Map from 'ol/Map.js';
import View from 'ol/View.js';
import TileLayer from 'ol/layer/Tile.js';
import OSM from 'ol/source/OSM.js';

const myLayer = new TileLayer({
    source: new TileWMS({
        url: 'https://wms{1-4}.kartes.lv/<span class="kijs_key"></span>/wgs/15/',
        attributions: ['<a href="https://balticmaps.eu" target="_blank">Jāņa sēta</a>'],
    }),
})

const myMap = new Map({
    view: new View({
        center: [24.11, 56.96],
        zoom: 12,
    }),
    layers: [
        myLayer, // add layers here
    ],
    target: 'mapId',
});

WMTS service

The layer created in this example uses the cadastral WMTS service, requesting the image by the x, y, and z coordinates of the tiles.

import TileLayer from 'ol/layer/Tile.js';
import XYZ from 'ol/source/XYZ.js';

const myLayer = new TileLayer({
    source: new XYZ({
        url: 'https://wms{1-4}.kartes.lv/<span class="kijs_key"></span>/wgs/cadastral/{z}/{x}/{y}',
        attributions: ['<a href="https://balticmaps.eu" target="_blank">Jāņa sēta</a>', '<a href="https://www.vzd.gov.lv/" target="_blank">VZD</a>'],
    })
})

Latvian coordinate system (LKS)

This example shows the use of the LKS coordinate system in the OpenLayers library.

  1. For map library to be able to correctly put map fragments together, LKS coordinate system must be defined. Projection parameters must be provided in proj4.defs(…) function.
  2. To create the LKS tile grid, tile origin coordinates and zoom level resolutions must be provided.
  3. Then the WMS service layer of the greyscale Jāņa sēta map is created, specifying the EPSG:3059 (LKS) projection and the previously created tile grid.
import TileLayer from 'ol/layer/Tile';
import TileWMS from 'ol/source/TileWMS';
import TileGrid from 'ol/tilegrid/TileGrid';
import proj4 from 'proj4';
import { register } from 'ol/proj/proj4';

proj4.defs(
    'EPSG:3059',
    '+proj=tmerc +lat_0=0 +lon_0=24 +k=0.9996 +x_0=500000 +y_0=-6000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +axis=neu',
)

const lksTileGrid = new TileGrid({
    origin: [-5682840.1444699997, 4997050.3242600001],
    resolutions: [
        6007.4787274574555,
        3003.7393637287278,
        1501.8695495724326,
        750.93477478621628,
        375.46751968503941,
        187.73362755058844,
        93.86694606722547,
        46.933473033612735,
        23.4667365168063,
        11.733235966471934,
        5.8666179832359671,
        2.9334412835492341,
        1.4665883498433665,
        0.73342646685293378,
        0.36671323342646689,
    ],
})

const myLayer = new TileLayer({
    source: new TileWMS({
        url: 'https://wms{1-4}.kartes.lv/<span class="kijs_key"></span>/lks/15bw/',
        projection: 'EPSG:3059',
        tileGrid: lksTileGrid,
    }),
})

Data sources

LĢIA - Latvian Geospatial Information Agency
VZD - Latvian State land service