timsc / mbtiles-cpp Goto Github PK

The repo description says it can read and write MBTiles files, but I'm only seeing source implementation for reading. Anything I'm missing, or is that not actually implemented?

----------------------im new to cpp and I can't read the error message...
----------------------below are part of the error message
In file included from /mbtiles-cpp/Source/vector_tile21/vector_tile.pb.cc:5:0:
/mbtiles-cpp/Source/vector_tile21/../../Include/vector_tile21/vector_tile.pb.h:17:2: error:
#error This file was generated by an older version of protoc which is incompatible with your Protocol Buffer headers. Please regenerate this file with a newer version of protoc.

/mbtiles-cpp/Source/vector_tile21/vector_tile.pb.cc: In function 'void vector_tile::protobuf_AssignDesc_vector_5ftile_2eproto()':
/mbtiles-cpp/Source/vector_tile21/vector_tile.pb.cc:60:19: error: no matching function for call to 'google::protobuf::internal::GeneratedMessageReflection::GeneratedMessageReflection(const google::protobuf::Descriptor*&, vector_tile::Tile*&, const int [1], int, int, int, const google::protobuf::DescriptorPool*, google::protobuf::MessageFactory*, long unsigned int)'
sizeof(Tile));

In file included from /usr/include/google/protobuf/stubs/common.h:41:0,
from /mbtiles-cpp/Source/vector_tile21/../../Include/vector_tile21/vector_tile.pb.h:9,
from /mbtiles-cpp/Source/vector_tile21/vector_tile.pb.cc:5:
/usr/include/google/protobuf/generated_message_reflection.h:574:3: note: candidate: google::protobuf::internal::GeneratedMessageReflection::GeneratedMessageReflection(const google::protobuf::internal::GeneratedMessageReflection&)
GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(GeneratedMessageReflection);
^
/usr/include/google/protobuf/generated_message_reflection.h:574:3: note: candidate expects 1 argument, 9 provided
In file included from /mbtiles-cpp/Source/vector_tile21/vector_tile.pb.cc:14:0:
/usr/include/google/protobuf/generated_message_reflection.h:169:3: note: candidate: google::protobuf::internal::GeneratedMessageReflection::GeneratedMessageReflection(const google::protobuf::Descriptor*, const google::protobuf::Message*, const int*, int, int, int, const void*, int, const google::protobuf::DescriptorPool*, google::protobuf::MessageFactory*, int, int, int)
GeneratedMessageReflection(const Descriptor* descriptor,
^~~~~~~~~~~~~~~~~~~~~~~~~~

Currently Cairo Egypt (specifically tile 9613,9626,14) is being calculated at roughly latitude -30 in the example project. I think this is due to a difference between the mbtile specification and the slippy tile spec that the tiley2lat and lat2tiley are expecting.

The mbtile format uses the "Tile Map Service Specification" which has incompatible tile indexing with slippy map tiles. The latitude functions seem to work when modified to be as follows:

double tiley2lat(int y, int z) 
{
	double n = pow(2.0,z);
	int ymax  = 1 << z;
	y = ymax - y - 1;
	double latRad = atan(sinh(M_PI*(1-(2*y/n))));
	return 180.0 / M_PI * latRad;
}

int lat2tiley(double lat, int z)
{
	int y = (int)(floor((1.0 - log( tan(lat * M_PI/180.0) + 1.0 / cos(lat * M_PI/180.0)) / M_PI) / 2.0 * pow(2.0, z)));
	int ymax  = 1 << z;
	y = ymax - y - 1;
	return y;
}

these modifications were found here https://alastaira.wordpress.com/2011/07/06/converting-tms-tile-coordinates-to-googlebingosm-tile-coordinates/

With the above changes Cairo is back at roughly latitude 30 comfortably above the equator.