# Error loading data

**URL:** <https://discourse.pangeo.io/t/error-loading-data/2935>\
**Category:** ICESat-2\
**Created:** [November 11, 2022, 3:28pm UTC](https://discourse.pangeo.io/t/error-loading-data/2935 "2022-11-11T15:28:27Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![idestromp](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.pangeo.io/idestromp/32/1927_2.png) [@idestromp](https://discourse.pangeo.io/u/idestromp)\
**Post date:** [November 11, 2022, 3:28pm UTC](https://discourse.pangeo.io/t/error-loading-data/2935/1 "2022-11-11T15:28:27Z")

</div>

Hi,  
New user here. I’m trying to get familiar with icepyx for downloading and loading up some ATL06 data for my upcoming thesis project. The following works well:

```auto
path_root = 'data/raw/external/IS2/'
pattern = "processed_ATL{product:2}_{datetime:%Y%m%d%H%M%S}_{rgt:4}{cycle:2}{orbistsegment:2}_{version:3}_{revision:2}.h5"
reader = ipx.Read(path_root, "ATL06", pattern) 
reader.vars.append(var_list=["h_li", "latitude", "longitude"])
ds = reader.load()

```

But if I try to add a variable to var\_list, e.g _‘bsnow\_h’_, the load method throws a KeyError (see below). I’m digging into the code to try and find where it is going wrong but thought I’d check here in case I’m missing something obvious in how to use it?

```auto
Traceback (most recent call last):

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/xarray/core/dataset.py", line 1394, in _construct_dataarray
    variable = self._variables[name]

KeyError: 'data_start_utc'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/spyder_kernels/py3compat.py", line 356, in compat_exec
    exec(code, globals, locals)

  File "/home/petter/study/master_thesis/untitled0.py", line 25, in <module>
    ds = reader.load()

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/icepyx/core/read.py", line 542, in load
    self._build_single_file_dataset(file, groups_list)

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/icepyx/core/read.py", line 692, in _build_single_file_dataset
    ds = Read._combine_nested_vars(

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/icepyx/core/read.py", line 497, in _combine_nested_vars
    is2ds = _make_np_datetime(is2ds, "data_start_utc")

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/icepyx/core/read.py", line 47, in _make_np_datetime
    if df[keyword].str.endswith("Z"):

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/xarray/core/dataset.py", line 1498, in __getitem__
    return self._construct_dataarray(key)

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/xarray/core/dataset.py", line 1396, in _construct_dataarray
    _, name, variable = _get_virtual_variable(

  File "/home/petter/anaconda3/envs/geospatial/lib/python3.9/site-packages/xarray/core/dataset.py", line 169, in _get_virtual_variable
    ref_var = variables[ref_name]

KeyError: 'data_start_utc'

```

There is a single file in path\_root which I downloaded via icepyx and the following settings:

```auto
short_name = 'ATL06'
spatial_extent =[18.13484764933186, 78.2490150412966, 19.482866502306077, 78.41061132951246]
date_range = ['2022-02-01', '2022-05-01']
rgts = ['0831'] 
spatial_extent
region = ipx.Query(short_name,
                   spatial_extent, 
                   date_range,
                   tracks = rgts,
                  )

```

Thanks - Petter

Edit: I noticed the similarities to this post: [Reader.load() issues with ATL06 - #5 by JennyFArthur](https://discourse.pangeo.io/t/reader-load-issues-with-atl06/2761/5). The file I’m trying to laod does include all the GTs though.