lawn (version 0.5.0)

lawn_idw: IDW

Description

Takes a FeatureCollection of points with known value, a power parameter, a cell depth, a unit of measurement and returns a FeatureCollection of polygons in a square-grid with an interpolated value property "IDW" for each grid cell. It finds application when in need of creating a continuous surface (i.e. rainfall, temperature, chemical dispersion surface...) from a set of spatially scattered points.

Usage

lawn_idw(controlPoints, valueField, b, cellWidth, units = "kilometers",
  lint = FALSE)

Arguments

controlPoints

A data-FeatureCollection, Sampled points with known value

valueField

(character) GeoJSON field containing the known value to interpolate on

b

(integer) Exponent regulating the distance-decay weighting

cellWidth

(integer) The distance across each cell

units

(character) used in calculating cellSize, can be degrees, radians, miles, or kilometers

lint

(logical) Lint or not. Uses geojsonhint. Takes up increasing time as the object to get linted increases in size, so probably use by default for small objects, but not for large if you know they are good geojson objects. Default: FALSE

Value

a data-FeatureCollection containing the dissolved polygons

See Also

Other grids: lawn_unkinkpolygon

Examples

# NOT RUN {
x <- '{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "marker-color": "#7e7e7e",
        "marker-size": "medium",
        "marker-symbol": "",
        "value": 4,
        "id": 4
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          9.155731201171875,
          45.47216977418841
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "marker-color": "#7e7e7e",
        "marker-size": "medium",
        "marker-symbol": "",
        "value": 99,
        "id": 2
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          9.195213317871094,
          45.53689620055365
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "marker-color": "#7e7e7e",
        "marker-size": "medium",
        "marker-symbol": "",
        "value": 10,
        "id": 1
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          9.175300598144531,
          45.49912810913339
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "marker-color": "#7e7e7e",
        "marker-size": "medium",
        "marker-symbol": "",
        "value": 6,
        "id": 3
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          9.231605529785156,
          45.49190839157102
        ]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "marker-color": "#7e7e7e",
        "marker-size": "medium",
        "marker-symbol": "",
        "value": 7,
        "id": 5
      },
      "geometry": {
        "type": "Point",
        "coordinates": [
          9.116249084472656,
          45.4391764115696
        ]
      }
    }
  ]
}'
lawn_idw(x, 'value', 0.5, 1)
# }