em-raw size

[tischi]

@constantinpape

How big is the em-raw (100nm^3) data set in MB?

[constantinpape]

Including all scale layers and segmentation:

$ du -sh em-raw.ome.zarr/
12G	em-raw.ome.zarr/

Only the raw data at 100nm^3 (to be more precise this is actually 80x80x100)

$du -sh em-raw.ome.zarr/s0/
8,2G	em-raw.ome.zarr/s0/

[tischi]

Thanks!

[tischi]

hi @constantinpape
cc @joshmoore

1. Could you also upload a version where the downsampling is based on powers of 3?
2. Do you already do something to account for initial anisotropy during downsampling?
3. Do do you average bin or something more fancy, like blurring and picking the central sample values?

cc @K-Meech (this is also relevant for your writer code, I think, because we should propose some good defaults).

[constantinpape]

• Could you also upload a version where the downsampling is based on powers of 3?

I can try to upload something later, but I would start from the same initial resolution, so we don't produce too much data.

• Do you already do something to account for initial anisotropy during downsampling?

Yes, I first downsample by [1, 2, 2] (in z, y, x axis convention).

• Do do you average bin or something more fancy, like blurring and picking the central sample values?

Here, I just take the average. I tried a couple of different options a while back and in my experience average worked best for EM data.

[tischi]

maybe then start [1,3,3,] ok?

[constantinpape]

maybe then start [1,3,3,] ok?

Sorry, I think what I wrote wasn't quite clear.

For the [3, 3, 3] downscaling I would start from (80, 80, 100) nm, which is (approximately) isotropic and always downscale by [3, 3, 3].

To start with [1, 3, 3], I would need to start from the full resolution again, which is (10, 10, 25) nm.
I would rather avoid doing that, because it would take a while and produce a large amount of data.

[tischi]

For the [3, 3, 3] downscaling I would start from (80, 80, 100) nm, which is (approximately) isotropic and always downscale by [3, 3, 3].

That's good!

[constantinpape]

@tischi I have uploaded the version downscaled with factors of 3 to embl/i2k-2020/em-raw3.ome.zarr/.