html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/2931#issuecomment-489656701,https://api.github.com/repos/pydata/xarray/issues/2931,489656701,MDEyOklzc3VlQ29tbWVudDQ4OTY1NjcwMQ==,1217238,2019-05-06T15:10:18Z,2019-05-06T15:10:18Z,MEMBER,"Yes, we'd like to remove this ""feature"" -- see https://github.com/pydata/xarray/issues/2368 for more discussion","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,438590881
https://github.com/pydata/xarray/issues/2931#issuecomment-487999904,https://api.github.com/repos/pydata/xarray/issues/2931,487999904,MDEyOklzc3VlQ29tbWVudDQ4Nzk5OTkwNA==,35968931,2019-04-30T15:32:18Z,2019-04-30T15:32:18Z,MEMBER,"So in xarray coordinates which have the same name as dimensions are given special status - they are known as ""dimension coordinates"". (Yes this is confusing and I think there are plans to make this structure clearer in the future.)

Dimension coordinates have to be 1D along the corresponding dimension, as indicated by the error message. However in your example you didn't specify the dimension which you want the coordinate `tt1` to have, because you didn't put it in a tuple with the desired dimensions like you did with the variable `var1`. If you add the desired dimension in then the error is no longer thrown, and I think gives you the dataset you want: 

```python
import xarray as xr
import pandas as p
import numpy as np

var1 = np.ones((364))
tt1=p.date_range('1/1/2018','12/30/2018')
tt1.name= 'time1_name'

var=xr.Dataset(
		data_vars={
			'var1':(('mytime1'),var1),
			},
		coords={
			'mytime1':(('mytime1'), tt1),
			}
)
```
which when printed gives

```
<xarray.Dataset>
Dimensions:  (mytime1: 364)
Coordinates:
  * mytime1  (mytime1) datetime64[ns] 2018-01-01 2018-01-02 ... 2018-12-30
Data variables:
    var1     (mytime1) float64 1.0 1.0 1.0 1.0 1.0 1.0 ... 1.0 1.0 1.0 1.0 1.0
```
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,438590881