gars_v2/src/helpers/data.js

Geo Assistant Research System

import fs from 'fs';
import readline from 'readline';
import error from './error';

class Data {
    constructor() {}
    read(datapath) {
        var p = new Promise((resolve, reject) => {
            var s = fs.createReadStream(datapath, { encoding: 'utf8' });
            var rl = readline.createInterface({
                input: s
            });
            var meta = [];
            var rows = [];
            var i = 0;
            rl.on('line', line => {
                line = line.trim();
                if (i < 5) {
                    meta.push(line);
                } else {
                    var row = line.split(/\s+/).map(Number);
                    rows.push(row);
                }
                i++;
            });
            rl.on('close', () => {
                this.parse(datapath, meta, rows);
                resolve();
            });
            s.on('error', e => {
                console.error(e);
                reject(e);
            });
        });

        return p;
    }

    parse(datapath, meta, rows) {
        this.FP = datapath;
        this.title = meta[0];
        this.unit = meta[1];
        this.cols = Number(meta[2]);
        this.rows = Number(meta[3]);
        this.llrange = meta[4].split(/\s+/).map(Number); 
        this.meta = meta;
        this.data = rows;

        var actualRows = this.data.length;
        var actualCols = this.data.length ? this.data[0].length : 0;
        if (actualRows != this.rows || actualCols != this.cols) {
            var msg = [
                'declared rows: ' + this.rows,
                'declared cols: ' + this.cols,
                'actual rows: ' + actualRows,
                'actual cols: ' + actualCols
            ].join('\n');
            error('Corrupted Data', msg);
        }
        console.log('map data loaded', `rows: ${this.rows} cols: ${this.cols}`);
    }

    // closed range to avoid data loss
    rangeAveX(x1, y1, x2, y2) {
        console.log('calculating average X for range', `x1:${x1},x2:${x2},y1:${y1},y2:${y2}`);
        x1 = Math.max(0, Math.floor(x1));
        y1 = Math.max(0, Math.floor(y1));
        x2 = Math.min(this.cols - 1, Math.ceil(x2));
        y2 = Math.min(this.rows - 1, Math.ceil(y2));
        var points = [];
        for (var x = x1; x < x2; x++) {
            var total = 0,
                count = 0;
            for (var y = y1; y < y2; y++) {
                var d = this.data[y][x];
                if (d === -999) continue;
                total += d;
                count++;
            }
            if (count === 0) continue;
            var ave = total / count;
            var x2lon = (x / this.cols) * (this.llrange[1] - this.llrange[0]) + this.llrange[0];
            points.push([x2lon, ave]);
        }
        console.log('average X computed', points.length, 'points');
        return points;
    }
    rangeAveY(x1, y1, x2, y2) {
        console.log('calculating average Y for range', `x1:${x1},x2:${x2},y1:${y1},y2:${y2}`);
        x1 = Math.max(0, Math.floor(x1));
        y1 = Math.max(0, Math.floor(y1));
        x2 = Math.min(this.cols - 1, Math.ceil(x2));
        y2 = Math.min(this.rows - 1, Math.ceil(y2));
        var points = [];
        for (var y = y1; y < y2; y++) {
            var total = 0,
                count = 0;
            for (var x = x1; x < x2; x++) {
                var d = this.data[y][x];
                if (d === -999) continue;
                total += d;
                count++;
            }
            if (count === 0) continue;
            var ave = total / count;
            var y2lat = - (y / this.rows) * (this.llrange[3] - this.llrange[2]) - this.llrange[2];
            points.push([y2lat, ave]);
        }
        console.log('average Y computed', points.length, 'points');
        return points;
    }
    accData(x1, y1, x2, y2) {
        x1 = Math.max(0, Math.floor(x1));
        y1 = Math.max(0, Math.floor(y1));
        x2 = Math.min(this.cols - 1, Math.ceil(x2));
        y2 = Math.min(this.rows - 1, Math.ceil(y2));
        var points = [];
        for (var y = y1; y < y2; y++) {
            for (var x = x1; x < x2; x++) {
                if (this.data[y][x] === -999) continue;
                points.push(this.data[y][x]);
            }
        }
        return points;
    }
    longitude(i) {
        return i * (this.llrange[1] - this.llrange[0]) / this.cols + this.llrange[0];
    }
    latitude(i) {
        return - i * (this.llrange[3] - this.llrange[2]) / this.rows - this.llrange[2];
    }
    longitudeText(i){
        var val = this.longitude(i).toFixed(3);
        var unit = val >= 0 ? 'E' : 'W';
        return val + '° ' + unit;
    }
    latitudeText(i){
        var val = this.latitude(i).toFixed(3);
        var unit = val >= 0 ? 'N' : 'S';
        return val + '° ' + unit;
    }
}

export default Data;