ShapeKit is a geometry library for iOS that aims to bridge GEOS with Apple's MapKit.
ShapeKit uses the MKShape Geometries (MKPolygon, MKPointAnnotation, MKPolyline) which were added to MapKit in iOS 4.0. It has been tested on the iPhone, and will most likely just work on the iPad when iOS 4 is released for it.
ShapeKit depends on GEOS. There is a build script in lib_src which will automate downloading and building the library for both ARM and x86 (simulator) and will copy the libraries and headers to ~/Developer. To use it, simply run the build_libs.sh script in the lib_src directory to install the libraries and headers to ~/Developer. Next, drag one copy each of libgeos.a and libgeos_c.a to the Frameworks folder in your project's Xcode window. Finally, double-click on the project's Target and in the Build tab of the Info window that pops up, add $(HOME)/$(SDK_DIR)/include to the Header Search Path, and $(HOME)/$(SDK_DIR)/lib to the Library Search Path. Now Xcode should be able to find the GEOS library.
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ShapeKitGeometries are standard cocoa objects
ShapeKitPoint *myPoint = [[ShapeKitPoint alloc] initWithCoordinate:CLLocationCoordinate2DMake(0, 0)]; -
ShapeKitGeometries have standard MKShape geometries for use with MapKit
myPoint.geometry.title = @"Centre of the Universe";myPoint.geometry.subtitle = @"The most awesome place in the world";[myMapKitView addAnnotation:myPoint.geometry] -
ShapeKitGeometries also have GEOS geometries for use with the GEOS C API
GEOSGeometry *bufferedPoint = GEOSBuffer(myPoint.geosGeom, 1, 0);(NOTE: the plan is to eventually abstract the underlying GEOS functions away behind Objective-C wrappers)
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GEOS functions are abstracted into Objective-C methods that operate directly on ShapeKitGeometries
ShapeKitPolygon *polygon = [[ShapeKitPolygon alloc] initWithWKT:@"POLYGON((-1 -1, -1 1, 1 1, 1 -1, -1 -1))"];[polygon containsGeometry:myPoint] \\ Returns YES
After following the instructions above to set up GEOS, simply drag the ShapeKit folder into Xcode. You will also need to add the CoreLocation and MapKit frameworks to your project. See the sample Xcode project for a simple example of a ShapeKit app.
The plan is to turn this into a more generic geo library for iOS with support for projections (through PROJ4) and vector data loading (though OGR).
This is free software; you can redistribute and/or modify it under the terms of the GNU Lesser General Public Licence as published by the Free Software Foundation. See the COPYING file for more information.