iPhone Note #20:Integrating Mapserver/TileCache to RouteMe

 61 [mapserver_australia_3857]
 62 type=MapServerLayer
 63 mapfile=/Users/rupert/projects/pelicancorp/DMOB/trunk/map/australia_3857.map
 64 layers=all
 65 extension=jpg
 66 bbox=-20037508.34, -20037508.34, 20037508.34, 20037508.34
 68 maxResolution=156543.033928041
 70 levels=20
 71 srs=EPSG:3857
 72 tms_type=google
 73 extent_type=loose
 74 spherical_mercator=true

//This would request to http://127.0.0.1/cgi-bin/mapserv
NSArray *arrayValues = [[NSArray alloc] initWithObjects:@"/path-to/australia_3857.map", @"all", @"png", @"EPSG:3857",nil];
NSArray *arrayKeys = [[NSArray alloc] initWithObjects:@"MAP", @"LAYERS", @"FORMAT", @"SRS", nil];
NSDictionary *wmsParameters = [[NSDictionary alloc] initWithObjects: arrayValues forKeys:arrayKeys ];

http://192.168.1.193:81/tilecache/tilecache.py?LAYERS=australia_3857&SRS=EPSG:3857&REQUEST=GetMap&SERVICE=WMS&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=png&VERSION=1.1.1&WIDTH=256&HEIGHT=256&BBOX=16828376.000000,-4006523.000000,16833268.000000,-4001631.000000

http://192.168.1.193:81/tilecache/tilecache.py?LAYERS=australia_3857&FORMAT=jpg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A3857&BBOX=16123932.497377,-4539747.9811239,16143500.376618,-4520180.1018829&WIDTH=256&HEIGHT=256

//Testing for Windows:TileCache - ?
NSArray *arrayValues = [[NSArray alloc] initWithObjects:@"australia_3857", @"png", @"EPSG:3857",nil]; //for WIndows
 
//TileCache URL Parameters:
NSArray *arrayKeys = [[NSArray alloc] initWithObjects:@"LAYERS", @"FORMAT", @"SRS", nil];

typedef struct {
	double x;
	double y;
} CGDoublePoint;
 
typedef struct { 
	CGDoublePoint ul; 
	CGDoublePoint lr; 
} CGXYRect;

#import "RMGenericMercatorWMSSource.h"
 
CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;}; 
CGFloat RadiansToDegrees(CGFloat radians) {return radians * 180/ M_PI;}; 
 
@implementation RMGenericMercatorWMSSource
 
-(id) initWithBaseUrl:(NSString *)baseUrl parameters:(NSDictionary *)params
{ 
	if (![super init]) 
		return nil; 
 
	// 156543.03392804062 for sideLength 256 pixels 
	// initialResolution = 2 * M_PI * 6378137 / [self tileSideLength];
	// specify here whatever the resolution is from tilecache.
	initialResolution = 156543.033928041;
 
	// 20037508.342789244 
	//originShift = 2 * M_PI * 6378137 / 2;
	//originShift = 20037508.342789244f;
	// specify here whatever the bbox is from tilecache.
	originShift = 20037508.32;
 
	NSLog(@"test initialResolution:%f originShift:%f", initialResolution, originShift);
 
	// setup default parameters
	// use official EPSG:3857 by default, user can override to 900913 if needed.
	wmsParameters = [[NSMutableDictionary alloc] initWithObjects:[[[NSArray alloc] initWithObjects:@"EPSG:3857",@"image/png",@"GetMap",@"1.1.1",@"WMS",nil] autorelease] 
											  forKeys:[[[NSArray alloc] initWithObjects:@"SRS",@"FORMAT",@"REQUEST",@"VERSION",@"SERVICE",nil] autorelease]];
	[wmsParameters addEntriesFromDictionary:params];
 
	// build WMS request URL template
	urlTemplate = [NSString stringWithString:baseUrl];
	NSEnumerator *e = [wmsParameters keyEnumerator];
	NSString *key;
	NSString *delimiter = @"";
	while (key = [e nextObject]) {
		urlTemplate = [urlTemplate stringByAppendingFormat:@"%@%@=%@",
					   delimiter,
					   [[key uppercaseString] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding], 
					   [[wmsParameters objectForKey:key] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]];
		delimiter = @"&";
	}
	int sideLength =  [self tileSideLength];
	urlTemplate = [[urlTemplate stringByAppendingFormat:@"&WIDTH=%d&HEIGHT=%d",sideLength,sideLength] retain];
	return self;
}
 
// implement in subclass?
-(NSString*) uniqueTilecacheKey
{
	return @"AbstractMercatorWMSSource";
}
 
-(NSString *)shortName
{
	return @"Generic WMS Source";
}
-(NSString *)longDescription
{
	return @"Generic WMS Source";
}
-(NSString *)shortAttribution
{
	return @"Generic WMS Source";
}
-(NSString *)longAttribution
{
	return @"Generic WMS Source";
}
 
-(float) minZoom
{
	return 1.0f;
}
-(float) maxZoom
{
	return 19.0f;
}
 
// Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:3857 
-(CGPoint) LatLonToMeters: (CLLocationCoordinate2D) latlon 
{ 
	CGPoint meters; 
	meters.x = latlon.longitude * originShift / 180; 
	meters.y = (log( tan((90.0 + latlon.latitude) * M_PI / 360.0 )) / (M_PI / 180.0)) * originShift / 180; 
	return meters; 
}
 
//Converts XY point from Spherical Mercator EPSG:3857 to lat/lon in WGS84 Datum 
-(CLLocationCoordinate2D) MetersToLatLon: (CGPoint) meters 
{ 
	CLLocationCoordinate2D latlon; 
	latlon.longitude = (meters.x / originShift) * 180.0; 
	latlon.latitude = (meters.y / originShift) * 180.0; 
	//latlon.latitude = - 180 / M_PI * (2 * atan( exp( latlon.latitude * M_PI / 180.0)) - M_PI / 2.0); 
	latlon.latitude = 180 / M_PI * (2 * atan( exp( latlon.latitude * M_PI / 180.0)) - M_PI / 2.0); 
	return latlon; 
} 
 
// Converts pixel coordinates in given zoom level of pyramid to EPSG:3857 
-(CGDoublePoint) PixelsToMeters: (int) px PixelY:(int)py atZoom:(int)zoom 
{ 
	double resolution = [self ResolutionAtZoom: zoom]; 
	CGDoublePoint meters; 
	double x = (px * resolution - originShift); 
	double y = (py * resolution - originShift); 
 
	meters.x = x;
	meters.y = y;
 
	NSLog(@"px: %d py: %d resolution: %f originShift: %f x: %f y: %f", px, py, resolution, originShift, x, y);
 
	return meters; 
} 
 
-(NSString*) tileURL: (RMTile) tile 
{ 
	//RMLatLongBounds tileBounds = [self TileLatLonBounds:tile];
	// Get BBOX coordinates in meters
	CGXYRect tileBounds = [self TileBounds:tile];
 
	NSString *url = [urlTemplate stringByAppendingFormat:@"&BBOX=%f,%f,%f,%f",
					 tileBounds.ul.x,
					 tileBounds.lr.y,
					 tileBounds.lr.x,
					 tileBounds.ul.y];
 
	NSLog(@"Tile %d,%d,%d yields %@",tile.zoom, tile.x, tile.y, url); 
 
	return url; 
} 
 
 
//Returns bounds of the given tile in EPSG:3857 coordinates 
-(CGXYRect)  TileBounds: (RMTile) tile 
{
	int sideLength =  [self tileSideLength];
 
	int zoom = tile.zoom;
	long twoToZoom = pow(2,zoom);
	CGXYRect tileBounds; 
	tileBounds.ul = [self PixelsToMeters: (tile.x * sideLength) 
								  PixelY: ((twoToZoom-tile.y) * sideLength) 
								  atZoom: zoom ]; 
	tileBounds.lr = [self PixelsToMeters: ((tile.x+1) * sideLength) 
								  PixelY: ((twoToZoom-tile.y-1) * sideLength) 
								  atZoom: zoom];
	return tileBounds; 
} 
 
//Resolution (meters/pixel) for given zoom level (measured at Equator) 
-(double) ResolutionAtZoom : (int) zoom 
{ 
	return initialResolution / pow(2,zoom); 
} 
 
@end