IntersectionDataset: better error message when no overlap

[adamjstewart]

To illustrate why this is needed, create two directories containing non-overlapping images, and run the following script:

from torch.utils.data import DataLoader

from torchgeo.datasets import Landsat8
from torchgeo.samplers import RandomGeoSampler

bands = ["B1", "B2", "B3"]

ds1 = Landsat8("data/dir1", bands=bands)
ds2 = Landsat8("data/dir2", bands=bands)

ds = ds1 & ds2
rs = RandomGeoSampler(ds, 256, 10)
dl = DataLoader(ds, sampler=rs)
for batch in dl:
    pass

Before

The previous error message was completely useless, and led to much confusion due to Toblerity/rtree#204:

Traceback (most recent call last):
  File "/Users/Adam/torchgeo/test.py", line 12, in <module>
    rs = RandomGeoSampler(ds, 256, 10)
  File "/Users/Adam/torchgeo/torchgeo/samplers/single.py", line 102, in __init__
    super().__init__(dataset, roi)
  File "/Users/Adam/torchgeo/torchgeo/samplers/single.py", line 37, in __init__
    roi = BoundingBox(*self.index.bounds)
  File "<string>", line 9, in __init__
  File "/Users/Adam/torchgeo/torchgeo/datasets/utils.py", line 246, in __post_init__
    raise ValueError(
ValueError: Bounding box is invalid: 'minx=1.7976931348623157e+308' > 'maxx=-1.7976931348623157e+308'

After

We now raise an error immediately when trying to compute the intersection with a clear and concise error message:

Traceback (most recent call last):
  File "/Users/Adam/torchgeo/test.py", line 11, in <module>
    ds = ds1 & ds2
  File "/Users/Adam/torchgeo/torchgeo/datasets/geo.py", line 134, in __and__
    return IntersectionDataset(self, other)
  File "/Users/Adam/torchgeo/torchgeo/datasets/geo.py", line 845, in __init__
    self._merge_dataset_indices()
  File "/Users/Adam/torchgeo/torchgeo/datasets/geo.py", line 859, in _merge_dataset_indices
    raise RuntimeError("Datasets have no spatiotemporal intersection")
RuntimeError: Datasets have no spatiotemporal intersection

Thanks to @TolgaAktas for reporting this!

[pmandiola]

Looks ok to me! Makes a lot of sense to raise this no overlapping exception too.