rasterio/tests/test_overviews.py

"""Tests of overview counting and creation."""

import numpy as np
import pytest

import rasterio
from rasterio.enums import OverviewResampling
from rasterio.enums import Resampling
from rasterio.errors import OverviewCreationError


def test_count_overviews_zero(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile) as src:
        assert src.overviews(1) == []
        assert src.overviews(2) == []
        assert src.overviews(3) == []


def test_build_overviews_one(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2]
        src.build_overviews(overview_factors, resampling=OverviewResampling.nearest)
        assert src.overviews(1) == [2]
        assert src.overviews(2) == [2]
        assert src.overviews(3) == [2]


def test_build_overviews_two(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2, 4]
        src.build_overviews(overview_factors, resampling=OverviewResampling.nearest)
        assert src.overviews(1) == [2, 4]
        assert src.overviews(2) == [2, 4]
        assert src.overviews(3) == [2, 4]


def test_build_overviews_bilinear(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2, 4]
        src.build_overviews(overview_factors, resampling=OverviewResampling.bilinear)
        assert src.overviews(1) == [2, 4]
        assert src.overviews(2) == [2, 4]
        assert src.overviews(3) == [2, 4]


def test_build_overviews_average(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2, 4]
        src.build_overviews(overview_factors, resampling=OverviewResampling.average)
        assert src.overviews(1) == [2, 4]
        assert src.overviews(2) == [2, 4]
        assert src.overviews(3) == [2, 4]


def test_build_overviews_gauss(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2, 4]
        src.build_overviews(overview_factors, resampling=OverviewResampling.gauss)
        assert src.overviews(1) == [2, 4]
        assert src.overviews(2) == [2, 4]
        assert src.overviews(3) == [2, 4]


def test_test_unsupported_algo(data):
    inputfile = str(data.join('RGB.byte.tif'))
    with pytest.raises(ValueError):
        with rasterio.open(inputfile, 'r+') as src:
            overview_factors = [2, 4]
            src.build_overviews(overview_factors, resampling=Resampling.q1)


def test_issue1333(data):
    """Fail if asked to create more than one 1x1 overview"""
    inputfile = str(data.join('RGB.byte.tif'))
    with pytest.raises(OverviewCreationError):
        with rasterio.open(inputfile, 'r+') as src:
            overview_factors = [1024, 2048]
            src.build_overviews(
                overview_factors, resampling=OverviewResampling.average)


def test_build_overviews_new_file(tmpdir, path_rgb_byte_tif):
    """Confirm fix of #1497"""
    dst_file = str(tmpdir.join('test.tif'))
    with rasterio.open(path_rgb_byte_tif) as src:
        with rasterio.open(dst_file, 'w', **src.profile) as dst:
            dst.write(src.read())
            overview_factors = [2, 4]
            dst.build_overviews(
                overview_factors, resampling=OverviewResampling.nearest)

    with rasterio.open(dst_file, overview_level=1) as src:
        data = src.read()
        assert data.any()


@pytest.mark.parametrize("ovr_levels", [[2], [3], [2, 4, 8]])
def test_ignore_overviews(data, ovr_levels):
    """open dataset with OVERVIEW_LEVEL=NONE, overviews should be ignored"""
    inputfile = str(data.join('RGB.byte.tif'))

    # Add overview levels to the fixture.
    with rasterio.open(inputfile, 'r+') as src:
        src.build_overviews(ovr_levels, resampling=Resampling.nearest)

    with rasterio.open(inputfile, OVERVIEW_LEVEL=-1) as src:
        assert src.overviews(1) == []
        assert src.overviews(2) == []
        assert src.overviews(3) == []


def test_decimated_no_use_overview(red_green):
    """Force ignore existing overviews when performing decimated read"""
    # Corrupt overview of red file by replacing red.tif.ovr with
    # green.tif.ovr.  We have a GDAL overview reading bug if green
    # pixels appear in a decimated read.
    green_ovr = red_green.join("green.tif.ovr")
    green_ovr.move(red_green.join("red.tif.ovr"))
    assert not green_ovr.exists()

    # Read the corrupted red overview.
    with rasterio.open(str(red_green.join("red.tif.ovr"))) as ovr:
        ovr_data = ovr.read(2)
        ovr_shape = ovr_data.shape
        assert (ovr_data == 204).all()  # Green pixels in band 2

    # Perform decimated read and ensure no use of file overview
    # (different from corrupted).
    with rasterio.open(str(red_green.join("red.tif")), OVERVIEW_LEVEL="NONE") as src:
        decimated_data = src.read(2, out_shape=ovr_shape)
        assert not np.array_equal(ovr_data, decimated_data)


def test_build_overviews_rms(data):
    """Make sure RMS resampling works"""
    inputfile = str(data.join('RGB.byte.tif'))
    with rasterio.open(inputfile, 'r+') as src:
        overview_factors = [2, 4]
        src.build_overviews(overview_factors, resampling=OverviewResampling.rms)
        assert src.overviews(1) == [2, 4]
        assert src.overviews(2) == [2, 4]
        assert src.overviews(3) == [2, 4]