Create map tiler/warper for map files

[bloritsch]

Main functions:

• Warp origin map tile to target projection (one each for the provided projection objects)
• Tile to projection tile sizes for target zoom levels they will be displayed
• Organize map files into folder hierarchy and naming scheme
• Insert references into spatial Lucene index
• Target file type will be 8-bit PNG with transparency

NOTE: this may simply build on the shape file loader.

[bloritsch]

Tiling is simple image splitting. Bitmap save as indexed PNG w/alpha: use PngBitmapDecoder/Encoder

var sourceDataset = Gdal.Open(...) var destDataset = GDal.AutoCreateWarpedVRT(sourceDataset, sourceWkt, destWkt, ResampleAlg, precision)

Dump data to Image IntPtr using destDataset.ReadRaster()

NOTE: reading a raster may require an intermediate step to change the destination bits before saving, but that is regular image data translation. destDataset transforms the origin bits to the new bits for the new projection.

Ex.

BitmapData data = bitmap.LockBits(destImageRect, ImageLockMode.ReadWrite, pixelFormat) int stride = bitmapData.Stride IntPtr buf = bitmapData.Scan0

readRaster to buf

bitmap.UnlockBits(data)

[bloritsch]

Good article here on reading the map files https://trac.osgeo.org/gdal/wiki/GdalOgrCsharpRaster