RasterSource.resolutions becomes List[CellSize] - #3124

Overview

This PR is intended to address usability issues around resampling RasterSource described in #3100

RasterSource.resolutions is not List[CellSize]. As discussed in the issue this removes the ability to provide GridBounds from RasterSource.resolutions to the RasterSource.read method of the same instance. The judgement call is that if each overview somehow has differing extent this is considered very unusual and can be diagnosed by further digging into RasterMetadata interface or through additional specialized API.

Grid.gridBounds are removed. This added a very confusing case where GridBounds could either be a window in some raster or describe the whole footprint of raster. Removing Grid.gridBounds goes a long way to remove that confusion. This is a recently added member to the class, so impact is judged to be small.

GridBounds.intersects(dimensions) - For those cases when we're checking for intersection with a raster we're using the new Dimensions class. Dimensions can be checked for intersection vs GridBounds and intersection of GridBounds and Dimensions is smaller Option[GridBounds].

Grid.dimensions becomes Dimensions[N] Instead of (N, N) - with addition of specialized API described above. Giving this a class goes a long way to clarify its usage in API. Note that this change results in fix-ups to tests that could be be caught by compiler due to checking for equality with "==". This is likely to happen in client code but should be easily fixed.

Checklist

• docs/CHANGELOG.rst updated, if necessary
• docs guides update, if necessary
• New user API has useful Scaladoc strings
• Unit tests added for bug-fix or new feature

Notes

gdal > console
[info] Starting scala interpreter...
Welcome to Scala 2.11.12 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_211).
Type in expressions for evaluation. Or try :help.

scala> import geotrellis.raster.gdal._
import geotrellis.raster.gdal._

scala> import geotrellis.raster.io.geotiff.{AutoHigherResolution, OverviewStrategy}
import geotrellis.raster.io.geotiff.{AutoHigherResolution, OverviewStrategy}

scala> import geotrellis.raster.resample._
import geotrellis.raster.resample._

scala> val rs = GDALRasterSource("/Users/eugene/proj/geotrellis/raster/data/vlm/aspect-tiled.tif")
rs: geotrellis.raster.gdal.GDALRasterSource = GDALRasterSource(/Users/eugene/proj/geotrellis/raster/data/vlm/aspect-tiled.tif,GDALWarpOptions(-of VRT -ovr AUTO))

scala> rs.resolutions
res0: List[geotrellis.raster.CellSize] = List(CellSize(20.0,20.0), CellSize(40.0,39.94082840236686), CellSize(79.7872340425532,79.88165680473372))

Closes #3100