First of all, thank you for your help @dcherian @max-sixty . I finally reproduced this problem. I put the ds.isel(time=[0], isoBaricInhPa=1).z[:, ::10, :][:, ::-1, :] to ds.isel(time=[0], isoBaricInhPa=1).z[:, ::10, ::10][:, ::-1, :] can make a minimal example.

``` import numpy as np import xarray as xr ds = xr.Dataset( { "z": ( ("time", "isoBaricInhPa", "latitude", "longitude"), np.ones((1, 5, 721, 1440)), ) }, coords={"latitude": np.linspace(-90, 90, 721)}, ).to_netcdf("test.nc") ds = xr.open_dataset('test.nc') a = ds.isel(time=[0], isoBaricInhPa=1).z[:, ::10, ::10][:, ::-1, :] print(a.sizes) print(a.shape) print(a)

Frozen({'time': 1, 'latitude': 73, 'longitude': 144}) (1, 73, 144) <xarray.DataArray 'z' (time: 1, latitude: 72, longitude: 144)> array([[[1., 1., ..., 1., 1.], [1., 1., ..., 1., 1.], ..., [1., 1., ..., 1., 1.], [1., 1., ..., 1., 1.]]]) Coordinates: * latitude (latitude) float64 90.0 87.5 85.0 82.5 ... -82.5 -85.0 -87.5 -90.0 Dimensions without coordinates: time, longitude ```

Don't bundle data — build a new example from a basic array and demonstrate the bug.

Since I don't know how the grib file is generated, I can't reproduce it. But the data I use is the ECWMF official website data converted by engine='cfgrib', this problem may be caused by the 'cfgrib' engine, although it is not very big wrong, but it's a hidden danger. I'm not competent enough, sorry to bother you.

What is data3? We need an example that I can paste into a blank notebook and will show the problem.

I packed them in one .zip this time ,the second-dimensional coordinates of variable a do not correspond to the data

But no, this is not sufficient — can you show your problem on an array like xr.DataArray(np.arange(12).reshape(2,3,4)), only adding extra as necessary? Please have another read of the links above showing how to minimize the examples.

Ok ,thanks. I try to simplify the problem on an array a = data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::10,::10][:, ::-1,:] ,my question is that the coordinates DO NOT correspond to the data, there is 73 on coordinates latitude but only the there is 72 only on real data latitude.

Sorry, this is the first time I use Github to report a problem, I don't understand it very well, it seems that I need to learn more. I have added a zip dile with a .ipynb file , don't know if it is ok?

------------------ 原始邮件 ------------------ 发件人: "Maximilian @.>; 发送时间: 2022年5月2日(星期一) 下午4:32 收件人: @.>; 抄送: @.>; @.>; 主题: Re: [pydata/xarray] error when using .sel() and [:, ::10, ::10][:, ::-1, :] (Issue #6560)

@jesieleo — I'm probably being unclear, and I'm sure you're well-intentioned, but this & the previous issues aren't constructive for either of us so far.

In the politest possible way: please make an issue that is complete and "copy & pastes into an IPython prompt or Binder notebook, returning the result.". You cannot reference data that is only on your computer. This will require work from your end to take the example you have there, and reduce it to the bare minimum.

— Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.Message ID: @.***>

isobaricInhPa是一个标量坐标，所以不适合我。如果我删除它，我无法重现结果，我两次都得到正确的结果。sel

First of all thanks for your answer. In fact, this was originally a vector coordinate, but I chose one to send u. This time I upload a version of isobaricInhPa which is a vector coordinate, please select.

The latitude should be 73 but 72 ,but,when I try to check latitude by itself, it works fine again, which makes me think it's a bug. ``` import xarray as xr data3 = xr.open_dataset('test0001.nc')

correct

a = data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::10,::10]

The latitude should be 73 but 72

wrong (latitude wrong,latituede is 72)

b = data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::-10,::10]

correct(latitude wrong,latituede is 73)

b = data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::-10,::10].latitude ```

latitude should be 73, but this is 72, and the coordinates do not correspond to the data

test0001.zip

It seem that when use sel() , [: , ::-1 , :] and [: , ::10 , ::10] at the same time will cause the second coord will wrong like this.

Why just when use sel and[: , ::-10 , ::10] ,it will goes wrong( the coordinates DO NOT correspond to the data) , but use sel and[: , ::10 , ::10] it goes right (the coordinates DO correspond to the data)? data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::10,::10][: ,::-1,:] #works wrong data3.sel(time='1979-1',isobaricInhPa=200).z[:, ::10,::10][: ,::1,:] #works right I think this is a bug.