http://t1.tianditu.gov.cn/DataServer?T=cva_w&x={x}&y={y}&l={zoom}

using UnityEngine;

public class TianDiTuLabels:MonoBehaviour
{
    private void Start()
    {
        if (OnlineMapsCache.instance != null)
        {
            OnlineMapsCache.instance.OnStartDownloadTile += OnStartDownloadTile;
            OnlineMapsCache.instance.OnLoadedFromCache += OnStartDownloadTile;
        }
        else OnlineMaps.instance.OnStartDownloadTile += OnStartDownloadTile;
    }

    private void OnStartDownloadTile(OnlineMapsTile tile)
    {
        StartDonwloadLabels(tile);
        OnlineMaps.instance.StartDownloadTile(tile);
    }

    private void StartDonwloadLabels(OnlineMapsTile tile)
    {
        OnlineMapsWWW www = OnlineMapsUtils.GetWWW("http://t1.tianditu.gov.cn/DataServer?T=cva_w&x=" + tile.x + "&y=" + tile.y + "&l=" + tile.zoom);
        www.OnComplete += OnLabelsDownloadComplete;
        www.customData = tile;
    }

    private void OnLabelsDownloadComplete(OnlineMapsWWW www)
    {
        OnlineMapsTile tile = www.customData as OnlineMapsTile;
        if (tile == null || tile.status == OnlineMapsTileStatus.disposed || tile.status == OnlineMapsTileStatus.error) return;

        Texture2D texture = new Texture2D(256, 256);
        www.LoadImageIntoTexture(texture);
        tile.overlayBackTexture = texture;
    }
}