worker.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"sync"

	"github.com/ryankurte/go-mapbox/lib"
	"github.com/ryankurte/go-mapbox/lib/base"
	"github.com/ryankurte/go-mapbox/lib/maps"
)

func terrainWorker(mapBox *mapbox.Mapbox, queue chan xyz, directory string, workwg *sync.WaitGroup) {
	for xyz := range queue {
		// fetch tile
		highDPI := false
		log.Println("Fetch tile", xyz)
		tile, err := mapBox.Maps.GetTile(maps.MapIDTerrainRGB, xyz.x, xyz.y, xyz.z, maps.MapFormatPngRaw, highDPI)
		if nil != err {
			// panic(err)
			log.Println(err)
			workwg.Done()
			continue
		}

		// log.Println("Parsing tile", xyz)
		// fileHandler, err := os.Create(fmt.Sprintf("tmp/%v_%v_%v.csv", xyz.x, xyz.y, xyz.z))
		// if nil != err {
		// 	panic(err)
		// }
		// defer fileHandler.Close()

		// create temp file
		basename := fmt.Sprintf("%v_%v_%v_*.csv", xyz.x, xyz.y, xyz.z)
		fileHandler, err := ioutil.TempFile(directory, basename)
		if nil != err {
			panic(err)
		}
		defer fileHandler.Close()
		//.end

		fmt.Fprintf(fileHandler, "x,y,z\n")

		for x := 0; x < tile.Bounds().Max.X; x++ {
			for y := 0; y < tile.Bounds().Max.Y; y++ {

				loc, err := tile.PixelToLocation(float64(x), float64(y))
				if nil != err {
					log.Println(err)
					continue
				}

				ll := base.Location{Latitude: loc.Latitude, Longitude: loc.Longitude}

				elevation, err := tile.GetAltitude(ll)
				if nil != err {
					log.Println(err)
					continue
				}

				line := fmt.Sprintf("%v,%v,%v\n", loc.Longitude, loc.Latitude, elevation)
				fmt.Fprintf(fileHandler, line)

			}
		}

		workwg.Done()
	}
}