# Read multiple tiff image using zarr

**URL:** <https://discourse.pangeo.io/t/read-multiple-tiff-image-using-zarr/726>\
**Category:** Data\
**Created:** [July 9, 2020, 3:08pm UTC](https://discourse.pangeo.io/t/read-multiple-tiff-image-using-zarr/726 "2020-07-09T15:08:06Z")\
**Posts on this page:** 1\
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**Author:** ![rsignell](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.pangeo.io/rsignell/32/447_2.png) [@rsignell](https://discourse.pangeo.io/u/rsignell)\
**Post date:** [January 20, 2021, 8:22pm UTC](https://discourse.pangeo.io/t/read-multiple-tiff-image-using-zarr/726/2 "2021-01-20T20:22:36Z")

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I’m guessing the poor performance to read a time series are because the data was stored in Zarr using the same chunking scheme as the original data (time=1, x=4400, y=4400)?

To allow time series extraction in a reasonable length of time, you would want something (time=144, x=400, y=400), which for floats or 32-bit integers would be about 100MB chunks.

If you used this chunking scheme for 2 years of hourly data, users who want to read a time series at a specified x,y location would read about the same number of chunks as a user who wants to read the entire x,y field at a specified time:

```auto
(4400*4400)/(400*400) = 121   
2*(365.25*24)/144 = 121.74

```

With a cluster of 30 workers, the read times would be a few seconds for each. Does this make sense?

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