JSON

Although GeoJSON is a universal geographical data format, in specific usage scenarios, data service personnel may not be familiar with GeoJSON, or do not have the tools to generate GeoJSON. Therefore, L7 defines the concept of Parser for data, and your data can be in any format. , just use the geographic information field corresponding to the specified data.

JSON

⚠️ json is not a standard geographical data structure, so be sure to set Parser when using it

json data parsing uses the corresponding JSON parser

parser

Supports two parsing methods

Simple analysis method

This method only supports analytical point data, or line segments with only two points, or arc data.

• type stringrequiredjson
• x stringPoint data represents longitude
• y stringPoint data represents latitude
• x1 stringlongitude
• x2 stringlatitude

If the data is point data, you only need to set the x,y fields.

If it is line segment or arc data, you need to know the coordinates of the starting and ending points, x, y, x1, y1

layer.source(data, {
  parser: {
    type: 'json',
    x: 'lng',
    y: 'lat',
  },
});

JSON data demo example

Universal parsing method

It can also analyze arbitrarily complex points, lines and surfaces.

• type stringrequiredjson
• coordinates arrayRequired, mainly used to express more complex formats, equivalent to the geojson coordinates attribute

layer.source(data, {
  parser: {
    type: 'json',
    coordinates: 'coord',
  },
});

Usage example

point data

Simple analysis

• type json
• x: longitude field
• y: latitude field

const data = [
  {
    lng: 112.345,
    lat: 30.455,
    value: 10,
  },
  {
    lng: 114.345,
    lat: 31.455,
    value: 10,
  },
];

layer.source(data, {
  parser: {
    type: 'json',
    x: 'lng',
    y: 'lat',
  },
});

general analysis

Point coodinates data format

const data = [
  {
    coord: [112.345, 30.455],
    value: 10,
  },
  {
    coord: [114.345, 32.455],
    value: 10,
  },
];

layer.source(data, {
  parser: {
    type: 'json',
    coordinates: 'coord',
  },
});

line data

Simple analysis

• type: json
• x stringlongitude
• y stringlatitude
• x1 stringlongitude
• x2 stringlatitude

Simple analysis only supports line segments composed of two points. It is mainly used when drawing arcs. You only need to specify the starting and ending point coordinates of the line segment.

const data = [
  {
    lng1: 112.345,
    lat1: 30.455,
    lng2: 112.345,
    lat2: 30.455,
    value: 10,
  },
  {
    lng1: 114.345,
    lat1: 31.455,
    lng2: 112.345,
    lat2: 30.455,
    value: 10,
  },
];

layer.source(data, {
  parser: {
    type: 'json',
    x: 'lng1',
    y: 'lat1',
    x1: 'lng1',
    y1: 'lat2',
  },
});

general analysis

Drawing line segments and arcs also supports using coordinates to organize data.

coordinates contains two coordinates, The first coordinate corresponds to x, y The second coordinate corresponds to x1, y1

const data = [
  {
    id: '1',
    coord: [
      [101.953125, 50.51342652633956],
      [119.17968749999999, 33.137551192346145],
    ],
  },
];
layer.source(data, {
  parser: {
    type: 'json',
    coordinates: 'coord',
  },
});

If you need to use drawing trajectory data, you need to specify the point sequence of the line through codinates.

coordinate format The coordinate field of geojson supports LineString, MultiLineString

Line coodinates data format

const data = [
  {
    name: 'path1',
    path: [
      [58.00781249999999, 32.84267363195431],
      [85.78125, 25.16517336866393],
      [101.953125, 41.77131167976407],
      [114.9609375, 39.639537564366684],
      [117.42187500000001, 28.613459424004414],
    ],
  },
];

Specify by coordinates when using

layer.source(data, {
  parser: {
    type: 'json',
    coordinates: 'path',
  },
});

area data

The coordinates field of surface data is relatively complex and does not support simple parsing methods.

general analysis

The coordinates field needs to be specified. The format is the same as the coordinates field of GeoJSON.

Face codinates data format

Note that surface data coord is a three-layer data structure

[
  {
    type: 'Polygon',
    geometryCoord: [
      [
        [115.1806640625, 30.637912028341123],
        [114.9609375, 29.152161283318915],
        [117.79541015625001, 27.430289738862594],
        [118.740234375, 29.420460341013133],
        [117.46582031249999, 31.50362930577303],
        [115.1806640625, 30.637912028341123],
      ],
    ],
  },
];

layer.source(data, {
  parser: {
    type: 'json',
    coordinates: 'geometryCoord',
  },
});