Scala，如何将（微风）矩阵转换为geoTiff图像？

Question

I have a matrix representing an image, in Breeze . For instance, each cell (x, y) holds a RGB value. I can save it as various image formats (GIF, Jpeg...) using Scrimage .

How can I generate a geoTiff image? I am looking at GeoTrellis but haven't figured out a straightforward way yet.

Answer 1

So you are talking about RGB image, potentially it means an int GeoTiff.

The code looks like (current snapshot version 1.0.0-SNAPSHOT ):

val matrix: Array[Array[Int]] = ???
val cols = ??? // matrix dimensions
val rows = ???
val extent: Extent = ??? // you need extent for geotiff
val crs: CRS = ??? // you need to know crs
val tile = IntArrayTile.empty(cols, rows) // create an empty tile

for {
  c <- 0 until cols
  r <- 0 until rows
} tile.set(c, r, matrix(c)(r))

val geotiff = SinglebandGeoTiff(tile, extent, crs) // it's a geotiff

geotiff.write("dir where you plan to save your geotiff")

However it would be a grayscaled geotiff, to persist an RGB image you may want to create three tiles, and to save everything as a Multiband GeoTiff.

val red: Tile = ???
val green: Tile = ???
val blue: Tile = ???

val mbtile = MultibandTile(red, green, bule)

val mbgeotiff = new MultibandGeoTiff(
  mbtile, 
  extent, 
  crs, 
  GeoTiffOptions(
    Striped, 
    NoCompression, 
    ColorSpace.RGB
  )
) // GeoTiff options setup is quite important, to set up `TIFFTAG_PHOTOMETRIC` tag
mbgeotiff.write("dir where you plan to save your geotiff")

But I am not familiar with Breeze API, we can discuss your use case in a GeoTrellis gitter channel or / and to provide more information there.