``` filslp = "ChonghuaYinData/prmsl.mon.mean.nc" filtmp = "ChonghuaYinData/air.sig995.mon.mean.nc" filprc = "ChonghuaYinData/precip.mon.mean.nc"

ds_slp = xr.open_dataset(filslp).sel(time=slice(str(yrStrt)+'-01-01', str(yrLast)+'-12-31'))

ds_slp outputs: <xarray.Dataset> Dimensions: (nbnds: 2, time: 480, x: 349, y: 277) Coordinates: * time (time) datetime64[ns] 1979-01-01 ... 2018-12-01 lat (y, x) float32 ... lon (y, x) float32 ... * y (y) float32 0.0 32463.0 64926.0 ... 8927325.0 8959788.0 * x (x) float32 0.0 32463.0 64926.0 ... 11264660.0 11297120.0 Dimensions without coordinates: nbnds Data variables: Lambert_Conformal int32 ... prmsl (time, y, x) float32 ... time_bnds (time, nbnds) float64 ... Attributes: Conventions: CF-1.2 centerlat: 50.0 centerlon: -107.0 comments:
institution: National Centers for Environmental Prediction latcorners: [ 1.000001 0.897945 46.3544 46.63433 ] loncorners: [-145.5 -68.32005 -2.569891 148.6418 ] platform: Model standardpar1: 50.0 standardpar2: 50.000001 title: NARR Monthly Means dataset_title: NCEP North American Regional Reanalysis (NARR) history: created 2016/04/12 by NOAA/ESRL/PSD references: https://www.esrl.noaa.gov/psd/data/gridded/data.narr.html source: http://www.emc.ncep.noaa.gov/mmb/rreanl/index.html References:
```

``` yrStrt = 1950 # manually specify for convenience yrLast = 2018 # 20th century ends 2018

clStrt = 1950 # reference climatology for SOI clLast = 1979

yrStrtP = 1979 # 1st year GPCP yrLastP = yrLast # match 20th century

latT = -17.6 # Tahiti lonT = 210.75
latD = -12.5 # Darwin lonD = 130.83

select grids of T and D

T = ds_slp.sel(lat=latT, lon=lonT, method='nearest') D = ds_slp.sel(lat=latD, lon=lonD, method='nearest') outputs:

---

ValueError Traceback (most recent call last) <ipython-input-27-6702b30f473f> in <module> 1 # select grids of T and D ----> 2 T = ds_slp.sel(lat=latT, lon=lonT, method='nearest') 3 D = ds_slp.sel(lat=latD, lon=lonD, method='nearest')

~\Anaconda3\lib\site-packages\xarray\core\dataset.py in sel(self, indexers, method, tolerance, drop, **indexers_kwargs) 2004 indexers = either_dict_or_kwargs(indexers, indexers_kwargs, "sel") 2005 pos_indexers, new_indexes = remap_label_indexers( -> 2006 self, indexers=indexers, method=method, tolerance=tolerance 2007 ) 2008 result = self.isel(indexers=pos_indexers, drop=drop)

~\Anaconda3\lib\site-packages\xarray\core\coordinates.py in remap_label_indexers(obj, indexers, method, tolerance, **indexers_kwargs) 378 379 pos_indexers, new_indexes = indexing.remap_label_indexers( --> 380 obj, v_indexers, method=method, tolerance=tolerance 381 ) 382 # attach indexer's coordinate to pos_indexers

~\Anaconda3\lib\site-packages\xarray\core\indexing.py in remap_label_indexers(data_obj, indexers, method, tolerance) 257 new_indexes = {} 258 --> 259 dim_indexers = get_dim_indexers(data_obj, indexers) 260 for dim, label in dim_indexers.items(): 261 try:

~\Anaconda3\lib\site-packages\xarray\core\indexing.py in get_dim_indexers(data_obj, indexers) 223 ] 224 if invalid: --> 225 raise ValueError("dimensions or multi-index levels %r do not exist" % invalid) 226 227 level_indexers = defaultdict(dict)

ValueError: dimensions or multi-index levels ['lat', 'lon'] do not exist ```

Does any know how fix to this problem?Thank you very much.

Originally posted by @JimmyGao0204 in https://github.com/pydata/xarray/issues/475#issuecomment-633172787