網(wǎng)絡(luò)地圖服務(wù)（WMS）

??????? 網(wǎng)絡(luò)地圖服務(wù)（WMS）利用具有地理空間位置信息的數(shù)據(jù)制作地圖狼忱。其中將地圖定義為地理數(shù)據(jù)可視的表現(xiàn)危号。能夠根據(jù)用戶的請(qǐng)求返回相應(yīng)的地圖（包括PNG，GIF，JPEG等柵格形式或者是SVG和WEB CGM等矢量形式）队腐。WMS支持網(wǎng)絡(luò)協(xié)議HTTP，所支持的操作是由URL定義的薪前。

??????? 先來(lái)分析一波服務(wù)鏈接：
一般情況給我們的是這樣的：http://... .../geoserver/xf/wms?service=WMS&version=1.1.0&request=GetMap&layers=zgwz_lzyz_f08&styles=&bbox=-1844.9489742784644,0.0,35699.99999999942,34437.74999999997&width=768&height=704&srs=EPSG:3857&format=application/openlayers

參數(shù)：

• service=WMS

• version=1.1.0 ： 版本（1.1...和1.3...在計(jì)算上有區(qū)別）

• request=GetMap

• layers=zgwz_lzyz_f08 ：圖層數(shù)組（這個(gè)參數(shù)如果錯(cuò)誤則不顯示）

• styles=

• bbox=-1844.9489742784644,0.0,35699.99999999942,34437.74999999997 : 盒子（顯示區(qū)域）一般是需要計(jì)算

• width=768

• height=704

• srs=EPSG:3857 ：坐標(biāo)類型 ：3857同900913為偽墨卡托投影润努，也被稱為球體墨卡托坐標(biāo)；4326為WGS84經(jīng)緯度坐標(biāo)

• format=application/openlayers ：格式示括，iOS用這個(gè)format=image/png

• TRANSPARENT=TRUE ：透明 true：可以看到高德底圖铺浇，false看不到高德底圖

• ==>http://... .../geoserver/xf/wms?SERVICE=WMS&VERSION=1.1.0&REQUEST=GetMap&LAYERS=zgwz_lzyz_f08_gd&TRANSPARENT=TRUE&STYLES=&WIDTH=762&HEIGHT=768&srs=EPSG:3857&FORMAT=image/png&BBOX=

一、高德地圖:

???????通過(guò)高德地圖 MATileOverlay 接口垛膝，添加 WMS 服務(wù)到地圖上

高德

???????1.自定義類WMSTileOverlay繼承自MATileOverlay

import UIKit

class WMSTileOverlay: MATileOverlay {
    var rootURL = ""
    var titleSize = 0
    var initialResolution = 0.0
    var originShift = 0.0
    var HALF_PI = 0.0
    var RAD_PER_DEGREE = 0.0
    var HALF_RAD_PER_DEGREE = 0.0
    var METER_PER_DEGREE = 0.0
    var DEGREE_PER_METER = 0.0
    
    /// 初始化
    /// - Parameter initRootURL: 在線地圖路徑&TRANSPARENT=TRUE&FORMAT=image/png&BBOX= 
    init?(rootURL initRootURL: String?) {
        super.init()
        rootURL = initRootURL ?? ""
        titleSize = 256
        initialResolution = 156543.03392804062////2*Math.PI*6378137/titleSize
        originShift = 20037508.342789244//周長(zhǎng)的一半 2*Math.PI*6378137/2.0
        HALF_PI = .pi / 2.0
        RAD_PER_DEGREE = .pi/180.0
        HALF_RAD_PER_DEGREE = .pi/360.0
        METER_PER_DEGREE = originShift/180.0//一度多少米
        DEGREE_PER_METER = 180.0/originShift//一米多少度
    }

    /**
    * @brief 以tile path生成URL鳍侣。用于加載tile,此方法默認(rèn)填充URLTemplate
    * @param path tile path
    * @return 以tile path生成tileOverlay
    */
    override func url(forTilePath path: MATileOverlayPath) -> URL {

        let strURL = "\(rootURL)\(titleBoundsBy(x: path.x, y: path.y, zoom: path.z) ?? "")"
        let url = URL(string: strURL)
        return url!
    }

    /**
    * @brief 加載被請(qǐng)求的tile,并以tile數(shù)據(jù)或加載tile失敗error訪問(wèn)回調(diào)block;默認(rèn)實(shí)現(xiàn)為首先用URLForTilePath去獲取URL,然后用異步NSURLConnection加載tile
    * @param path   tile path
    * @param result 用來(lái)傳入tile數(shù)據(jù)或加載tile失敗的error訪問(wèn)的回調(diào)block
    */
    override func loadTile(at path: MATileOverlayPath, result: @escaping(Data?, Error?) -> Void) {
        let url = self.url(forTilePath: path)
        let request = NSMutableURLRequest(url: url)
        request.httpMethod = "GET"
        let session = URLSession.shared
        session.dataTask(with: request as URLRequest, completionHandler: {(data, response, error) in
            if error != nil {
                #if DEBUG
                print("Error downloading tile")
                #endif
                result(nil, error)
            }
            else {
                result(data, nil)
            }
        }).resume()
    }
    
    /// 取消請(qǐng)求瓦片，當(dāng)?shù)貓D顯示區(qū)域發(fā)生變化時(shí)吼拥，會(huì)取消顯示區(qū)域外的瓦片的下載, 當(dāng)disableOffScreenTileLoading=YES時(shí)會(huì)被調(diào)用倚聚。since 5.3.0
    /// - Parameter path: path
    override func cancelLoadOfTile(at path: MATileOverlayPath) {
        super.cancelLoadOfTile(at: path)
    }

    /**
    * 根據(jù)瓦片的x/y等級(jí)返回瓦片范圍
    *
    * @param tx
    * @param ty
    * @param zoom
    * @return url
    */
    func titleBoundsBy(x: Int, y: Int, zoom: Int) -> String? {
        let minX = pixels2Meters(x * titleSize, zoom: zoom)
        let maxY = -pixels2Meters(y * titleSize, zoom: zoom)
        let maxX = pixels2Meters(((x + 1) * titleSize), zoom: zoom)
        let minY = -pixels2Meters(((y + 1) * titleSize), zoom: zoom)
        
        return "\(minX),\(minY),\(maxX),\(maxY)"
    }

    /**
    * 根據(jù)像素、等級(jí)算出坐標(biāo)
    *
    * @param p p
    * @param zoom z
    * @return double
    */
    func pixels2Meters(_ p: Int, zoom: Int) -> Double {
        return Double(p) * resolution(zoom) - originShift
    }

    /**
    * 計(jì)算分辨率
    *
    * @param zoom z
    * @return double
    */
    func resolution(_ zoom: Int) -> Double {
        return initialResolution / (pow(2.0, Double(zoom)))
    }
}

???????2.在地圖控制器MapController調(diào)用

import UIKit

class MapController: UIViewController {
    let tileOverlay = WMSTileOverlay.init(rootURL: "http://... .../geoserver/haitu/wms?SERVICE=WMS&VERSION=1.1.0&REQUEST=GetMap&LAYERS=haitu:gis_t_landuse_a&TRANSPARENT=TRUE&STYLES=&srs=EPSG:3857&FORMAT=image/png&BBOX=")
    
    override func viewDidLoad() {
        super.viewDidLoad()
        let map = MAMapView(frame: frame: view.bounds)
        mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        mapView.setCenter(CLLocationCoordinate2D(latitude: 39.97000000, longitude: 116.3300000), zoomLevel: 20, animated: false)
        tileOverlay?.disableOffScreenTileLoading = true//停止不在顯示區(qū)域的瓦片下載
        mapView.add(tileOverlay)
        view.addSubview(mapView)
    }
}

???????3.異常處理

?????????（1）WMS服務(wù)地圖沒(méi)有坐標(biāo)：會(huì)導(dǎo)致圖層不能顯示在正確的位置凿可，這時(shí)候圖層會(huì)顯示在地圖的（0惑折，0）坐標(biāo)位置（非洲），排查的方法就是將地圖中心設(shè)置在（0枯跑，0）坐標(biāo)惨驶，然后放大。解決辦法就是制圖工程師給你個(gè)帶坐標(biāo)的圖敛助。

?????????（2）圖層疊加了很多次：第一出現(xiàn)這種情況有可能是我們自己對(duì)圖層做的緩存引起的粗卜。可以刪除緩存試試纳击。

?????????（3）出現(xiàn)柵格：這種情況有可能發(fā)布的圖有問(wèn)題续扔，或者bbox參數(shù)計(jì)算出現(xiàn)了問(wèn)題。出現(xiàn)這種情況的原因很多焕数，歡迎補(bǔ)充纱昧。

?????????（4）坐標(biāo)系不同、WMS版本1.1和1.3：如果WMS服務(wù)給的是84坐標(biāo)系百匆，疊加到高德上會(huì)出現(xiàn)偏移砌些，可以讓制圖工程師出一個(gè)高德坐標(biāo)系的圖，也可以我們自己在代碼里做加匈，會(huì)有一點(diǎn)計(jì)算量存璃，代碼如下：

???????????在第1步自定義類WMSTileOverlay中的方法func titleBoundsBy(x: Int, y: Int, zoom: Int) -> String?更改

    /**
    * 根據(jù)瓦片的x/y等級(jí)返回瓦片范圍
    *
    * @param tx
    * @param ty
    * @param zoom
    * @return url
    */
    func titleBoundsBy(x: Int, y: Int, zoom: Int) -> String? {
        let minX = pixels2Meters(x * titleSize, zoom: zoom)
        let maxY = -pixels2Meters(y * titleSize, zoom: zoom)
        let maxX = pixels2Meters(((x + 1) * titleSize), zoom: zoom)
        let minY = -pixels2Meters(((y + 1) * titleSize), zoom: zoom)
        
        return "\(minX),\(minY),\(maxX),\(maxY)"
    }

???????????改為

    /**
    * 根據(jù)瓦片的x/y等級(jí)返回瓦片范圍
    *
    * @param tx
    * @param ty
    * @param zoom
    * @return url
    */
    func titleBoundsBy(x: Int, y: Int, zoom: Int) -> String? {
        var minX = pixels2Meters(x * titleSize, zoom: zoom)
        var maxY = -pixels2Meters(y * titleSize, zoom: zoom)
        var maxX = pixels2Meters(((x + 1) * titleSize), zoom: zoom)
        var minY = -pixels2Meters(((y + 1) * titleSize), zoom: zoom)
        
        //轉(zhuǎn)換成經(jīng)緯度
        minX = meters2Lon(minX)
        minY = meters2Lat(minY)
        maxX = meters2Lon(maxX)
        maxY = meters2Lat(maxY)
        
        //轉(zhuǎn)換目標(biāo)經(jīng)緯度為高德坐標(biāo)系。
        let amapcoord = AMapCoordinateConvert(CLLocationCoordinate2DMake(CLLocationDegrees(minY), CLLocationDegrees(minX)), type)
        minY = amapcoord.latitude
        minX = amapcoord.longitude
        let maxAmapcoord = AMapCoordinateConvert(CLLocationCoordinate2DMake(CLLocationDegrees(maxY), CLLocationDegrees(maxX)), type)
        maxY = maxAmapcoord.latitude
        maxX = maxAmapcoord.longitude
        
        //轉(zhuǎn)換成墨卡托
        minX = lon2Meters(minX)
        minY = lat2Meters(minY)
        maxX = lon2Meters(maxX)
        maxY = lat2Meters(maxY)
        
        //有博客提到1.1版本和1.3版本有區(qū)別雕拼，沒(méi)有嘗試過(guò)纵东，如果你遇到了歡迎補(bǔ)充
        result = "\(minX),\(minY),\(maxX),\(maxY)" //1.1
        //result = "\(minX),\(minY),\(maxX),\(maxY)"http://1.3
        
        return result
    }
    
    //////添加坐標(biāo)轉(zhuǎn)換相應(yīng)的方法
    /**
    * X米轉(zhuǎn)經(jīng)緯度
    */
    func meters2Lon(_ mx: Double) -> Double {
        let lon = mx * DEGREE_PER_METER
        return lon
    }

    /**
    * Y米轉(zhuǎn)經(jīng)緯度
    */
    func meters2Lat(_ my: Double) -> Double {
        var lat = my * DEGREE_PER_METER
        lat = 180.0 / .pi * (2 * atan(exp(lat * RAD_PER_DEGREE)) - HALF_PI)
        return lat
    }
    
    /**
    * X經(jīng)緯度轉(zhuǎn)米
    */
    func lon2Meters(_ lon: Double) -> Double {
        let mx = lon * METER_PER_DEGREE
        return mx
    }
    
    /**
    * Y經(jīng)緯度轉(zhuǎn)米
    */
    func lat2Meters(_ lat: Double) -> Double {
        var my = log(tan((90 + lat) * HALF_RAD_PER_DEGREE))/(RAD_PER_DEGREE)
        my = my * METER_PER_DEGREE
        return my
    }

二、Mapbox地圖:

?????????????建議：做室內(nèi)地圖的用Mapbox啥寇，因?yàn)镸apbox縮放級(jí)別可以達(dá)到1米的效果偎球。

image

???????1.Mapbox的WMS服務(wù)和添加?xùn)鸥駡D像是一樣的洒扎，甚至不需要我們做修改,唯一需要注意的是參數(shù)：bbox={bbox-epsg-3857}

import UIKit
import Mapbox

class ViewController: UIViewController, MGLMapViewDelegate {
    var mapView: MGLMapView!
    var rasterLayer: MGLRasterStyleLayer?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        mapView = MGLMapView(frame: view.bounds)
        mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        
        mapView.setCenter(CLLocationCoordinate2D(latitude: 39.97000000, longitude: 116.3300000), zoomLevel: 20, animated: false)
        
        mapView.delegate = self
        
        view.addSubview(mapView)
        
        // Add a UISlider that will control the raster layer’s opacity.
        addSlider()
    }
    
    func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {
        // Add a new raster source and layer.
        let source = MGLRasterTileSource(identifier: "stamen-watercolor", tileURLTemplates: ["http://.../geoserver/xf/wms?service=WMS&version=1.1.0&request=GetMap&layers=zgwz_lzyz_f08_3857&styles=&bbox={bbox-epsg-3857}&width=768&height=704&srs=EPSG:3857&format=image/png"], options: [ .tileSize: 256 ])
        let rasterLayer = MGLRasterStyleLayer(identifier: "stamen-watercolor", source: source)
        
        style.addSource(source)
        style.addLayer(rasterLayer)
        
        self.rasterLayer = rasterLayer
    }
    
    @objc func updateLayerOpacity(_ sender: UISlider) {
        rasterLayer?.rasterOpacity = NSExpression(forConstantValue: sender.value as NSNumber)
    }
    
    func addSlider() {
        let padding: CGFloat = 10
        let slider = UISlider(frame: CGRect(x: padding, y: self.view.frame.size.height - 44 - 30, width: self.view.frame.size.width - padding *  2, height: 44))
        slider.minimumValue = 0
        slider.maximumValue = 1
        slider.value = 1
        slider.isContinuous = false
        slider.addTarget(self, action: #selector(updateLayerOpacity), for: .valueChanged)
        view.insertSubview(slider, aboveSubview: mapView)
        if #available(iOS 11.0, *) {
            let safeArea = view.safeAreaLayoutGuide
            slider.translatesAutoresizingMaskIntoConstraints = false
            let constraints = [
                slider.bottomAnchor.constraint(equalTo: safeArea.bottomAnchor, constant: -mapView.logoView.bounds.height - 10),
                slider.widthAnchor.constraint(equalToConstant: self.view.frame.size.width - padding *  2),
                slider.centerXAnchor.constraint(equalTo: safeArea.centerXAnchor)
            ]
            
            NSLayoutConstraint.activate(constraints)
        } else {
            slider.autoresizingMask = [.flexibleTopMargin, .flexibleLeftMargin, .flexibleRightMargin]
        }
    }
}