Fix numerical errors

[jdries]

Overview

When working in epsg:4326 coordinates, I recently observed separate bugs caused by the same problem. Basically transformations between geographical coordinates and grid coordinates where wrong due to floating point imprecision.
In both cases, grid coordinates were calculated as doubles and resulted in e.g. 4.9999999 but were done floored (toLong) resulting in 4.

This resulted in an actual pixel shift in one case, and in another case a missing row of pixels at the bottom of a saved geotiff.

Checklist

• ./CHANGELOG.md updated, if necessary. Link to the issue if closed, otherwise the PR.
• Unit tests added for bug-fix or new feature

Notes

Optional. Ancillary topics, caveats, alternative strategies that didn't work out, anything else.

Closes #XXX

[jdries]

Found a simple test that exposes the issue. It's all about gridextents that are in fact aligned, but due to very small numerical differences, things go wrong. Still have to figure out where and how to integrate this as part of geotrellis unit tests.

  val targetBounds = GridBounds(55L,103,55+73,103+111)
   val ge = GridExtent[Long](Extent(1.8973214288275528, 49.352678585684544, 6.299107143119465, 51.7276785856839), CellSize(0.008928571428584,0.008928571428568996))
   val targetExtent = ge.extentFor(targetBounds)

   //second, aligned extent based on a LayoutDefinition
   val ge2 = GridExtent[Long](Extent(2.3883928573996727, 49.66517858568254, 3.5312500002584244, 50.80803572854129), CellSize(0.008928571428583998,0.008928571428583998))

   //gridextents have to be aligned for test to be valid
   //basically copy of geotrellis.layer.LayoutTileSource#requireGridAligned
   requireGridAligned(ge,ge2)
   val resultingBounds = ge2.gridBoundsFor(targetExtent)


   assertEquals(targetBounds.height,resultingBounds.height)
   assertEquals(targetBounds.width,resultingBounds.width)

[pomadchin]

@jdries a nice find! Could you add this unit test?

[pomadchin]

🔥 Thx for a nice PR, but tests don't compile! Once the CI is green, I'll merge it.

[pomadchin]

Tests don't compile!

Suggested change

	targetBounds.height should be resultingBounds.height
	targetBounds.width should be resultingBounds.width
	targetBounds.height shouldBe resultingBounds.height
	targetBounds.width shouldBe resultingBounds.width