比例尺与层级的转换

double ImageTile::scale2Level(double scale) //  //比例转换为层级
{
	//实际距离
	double mapdis = 0.0254 * ((double)tilesize / 96.0)*scale;
	double x, y, x1, y1;
	ImageRowCol2Projection(m_adfGeoTransform, 0, 0, x, y);
	ImageRowCol2Projection(m_adfGeoTransform, tilesize, tilesize, x1, y1);
	double srcscale = (x1 - x) / (0.0254 * ((double)tilesize / 96.0));
	if (scale >= srcscale)
	{
		double level = mapdis / (x1 - x);
		return fabs(level)*m_adfGeoTransform[1];
	}
	else
	{
		double s = mapdis / (x1 - x);
		return fabs(s)*m_adfGeoTransform[1];
	}
	return 1;
}


double  ImageTile::level2scale(double level) //计算当前层级比例尺
{
	//return 1.0 / (0.0254 / (2 * 96));
	//地图距离
	double mapdis = 0.0254 * ((double)tilesize / 96.0);
	//实际距离
	double x, y, x1, y1;
	TDRasterCommon::ImageRowCol2Projection(m_adfGeoTransform, 0, 0, x, y);
	TDRasterCommon::ImageRowCol2Projection(m_adfGeoTransform, tilesize*level, tilesize*level, x1, y1);
	return (x1 - x) / mapdis;
}