Computing footprint error
Hi Daniel,
I am running into the following error, which I am not able to fix (see error message further down)
Data overlap. Same projection, type, source, nodata, both are overlapping
* ref image doesn't have super great quality, this was more a technical test. Same error in other places
[**Data download**](https://drive.google.com/file/d/1ZW16u94mrqcq4aDqppHrylGxfZOv6194/view?usp=sharing)

I tried to play around with no data (with, without, image size, etc.)
Platform:
* Windows 10
* Anaconda environment with python 3.7.X
* arosics (1.4.3) - same error with higher version
**Input**
```
REFERENCE = r'reference_image\reference.tif'
INFILE = r'input_images\target.tif'
outfile = r'output_files\out.tif'
```
```
# detect and correct global spatial shift
CR = COREG(REFERENCE, INFILE,
max_shift=200, path_out=outfile,
fmt_out='GTIFF',
out_crea_options=['COMPRESS=DEFLATE'],
r_b4match=1,
s_b4match=1)
```
**Output**
> Calculating footprint polygon and actual data corner coordinates for reference image...
>
> Polygonize progress |==================================================| 100.0% Complete => 0:00:01
>
> ---------------------------------------------------------------------------
> AssertionError Traceback (most recent call last)
> <ipython-input-27-23b3a79291b3> in <module>
> 1 # detect and correct global spatial shift
> ----> 2 CR = COREG(REFERENCE, infile,
> 3 max_shift=200, path_out=outfile,
> 4 fmt_out='GTIFF',
> 5 out_crea_options=['COMPRESS=DEFLATE'],
>
> ~\AppData\Local\Continuum\anaconda3\envs\arosics2\lib\site-packages\arosics\CoReg.py in __init__(self, im_ref, im_tgt, path_out, fmt_out, out_crea_options, r_b4match, s_b4match, wp, ws, max_iter, max_shift, align_grids, match_gsd, out_gsd, target_xyGrid, resamp_alg_deshift, resamp_alg_calc, footprint_poly_ref, footprint_poly_tgt, data_corners_ref, data_corners_tgt, nodata, calc_corners, binary_ws, mask_baddata_ref, mask_baddata_tgt, CPUs, force_quadratic_win, progress, v, path_verbose_out, q, ignore_errors)
> 398 # try:
> 399 gdal.AllRegister()
> --> 400 self._get_image_params()
> 401 self._set_outpathes(im_ref, im_tgt)
> 402 self.grid2use = 'ref' if self.shift.xgsd <= self.ref.xgsd else 'shift'
>
> ~\AppData\Local\Continuum\anaconda3\envs\arosics2\lib\site-packages\arosics\CoReg.py in _get_image_params(self)
> 532
> 533 def _get_image_params(self) -> None:
> --> 534 self.ref = GeoArray_CoReg(self.params, 'ref')
> 535 self.shift = GeoArray_CoReg(self.params, 'shift')
> 536
>
> ~\AppData\Local\Continuum\anaconda3\envs\arosics2\lib\site-packages\arosics\CoReg.py in __init__(self, CoReg_params, imID)
> 116
> 117 with warnings.catch_warnings(record=True) as w:
> --> 118 _ = self.footprint_poly # execute getter
> 119
> 120 if len(w) > 0 and 'disjunct polygone(s) outside' in str(w[-1].message):
>
> ~\AppData\Local\Continuum\anaconda3\envs\arosics2\lib\site-packages\geoarray\baseclasses.py in footprint_poly(self)
> 499
> 500 # validation
> --> 501 assert not polyVertices_outside_poly(self._footprint_poly, self.box.mapPoly, tolerance=1e-5), \
> 502 "Computing footprint polygon for %s '%s' failed. The resulting polygon is partly or completely " \
> 503 "outside of the image bounds." % (self.__class__.__name__, self.basename)
>
> AssertionError: Computing footprint polygon for GeoArray_CoReg 'reference' failed. The resulting polygon is partly or completely outside of the image bounds.
issue