pacificclimate/climate-explorer-frontend

// Data service for ncWMS HTTP API requests.
// Includes both HTTP request functions and supporting functions.

import axios from "axios/index";
import _ from "lodash";

export function getBaseWMSParams({
  dataset,
  filepath,
  variableId,
  wmsTime,
  opacity,
  logscale,
  range,
}) {
  // The dataset identifier can be either a dynamic dataset identifier, which
  // involves the full filepath, or a simple dataset identifier, which uses
  // just the dataset unique_id. Default behaviour is "simple".
  const datasetId =
    process.env.REACT_APP_MAP_LAYER_ID_TYPE === "dynamic"
      ? `${process.env.REACT_APP_MAP_LAYER_ID_PREFIX}${filepath}`
      : dataset;
  const fixedParams = {
    layers: `${datasetId}/${variableId}`,
    time: wmsTime,
    noWrap: true,
    format: "image/png",
    transparent: true,
    numcolorbands: 249,
    version: "1.1.1",
    srs: "EPSG:4326",
    logscale,
    opacity,
  };

  if (logscale !== "true" || _.isUndefined(range)) {
    return fixedParams;
  }

  const min = Math.max(range.min, Number.EPSILON);
  const max = Math.max(range.max, Number.EPSILON * 2);
  return Object.assign(fixedParams, {
    colorscalerange: `${min},${max}`,
    abovemaxcolor: "transparent",
    belowmincolor: "transparent",
  });
}

export function getRasterWMSParams({ palette, ...rest }) {
  return Object.assign(getBaseWMSParams(rest), {
    styles: `default-scalar/${palette}`,
  });
}

export function getIsolineWMSParams({ palette, ...rest }) {
  return Object.assign(getBaseWMSParams(rest), {
    styles: `colored_contours/${palette}`,
  });
}

export function getAnnotatedWMSParams(props) {
  return Object.assign(getBaseWMSParams(props), {
    styles: `contours`,
  });
}

export function getWMSParams(layerType, props) {
  // Return parameters required for a call to the ncWMS tile layer API.
  // TODO: simplify
  if (layerType === "raster") {
    return getRasterWMSParams(props);
  } else if (layerType === "isoline") {
    return getIsolineWMSParams(props);
  } else if (layerType === "annotated") {
    return getAnnotatedWMSParams(props);
  }
}

export function getLayerMinMax(layer, props, bounds) {
  // Request min and max values from ncWMS layer.
  // Returns a promise for the request response.

  const { layers, version, srs, time } = getWMSParams(layer, props[layer]);

  return axios(process.env.REACT_APP_NCWMS_URL, {
    params: {
      styles: "default-scalar",
      request: "GetMetadata",
      item: "minmax",
      crs: props.srs, // TODO: ?? wrong (undefined) but it works anyway; incorrect in original code
      elevation: 0,
      width: 100,
      height: 100,
      bbox: `${bounds.getWest()},${bounds.getSouth()},${bounds.getEast()},${bounds.getNorth()}`,
      layers,
      version,
      srs,
      time,
    },
  });
}