# Harp and process nc files of Sentinel 5P

**URL:** https://forum.atmospherictoolbox.org/t/harp-and-process-nc-files-of-sentinel-5p/372
**Category:** HARP
**Tags:** sentinel-5p, python
**Created:** [July 18, 2021, 10:25pm UTC](https://forum.atmospherictoolbox.org/t/harp-and-process-nc-files-of-sentinel-5p/372 "2021-07-18T22:25:53Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![sara](https://forum.atmospherictoolbox.org/user_avatar/forum.atmospherictoolbox.org/sara/32/172_2.png) [@sara](https://forum.atmospherictoolbox.org/u/sara)
#### Post date: [July 18, 2021, 10:25pm UTC](https://forum.atmospherictoolbox.org/t/harp-and-process-nc-files-of-sentinel-5p/372/1 "2021-07-18T22:25:53Z")

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Hello everyone,

I am trying to do an air quality study for the Canary Islands (Spain) using Sentinel 5p data. For now I can download the satellite data but when processing the files using harp there is something wrong. I am using this code as an example: [GitHub - SIGTE-UdG/NO2\_Sentinel5p](https://github.com/SIGTE-UdG/NO2_Sentinel5p)  
And here is my code. (this code is only for Tenerife island):

def process\_nc\_files:

```
file_names = []
products = []

i = 0
for filename in os.listdir(os.path.dirname(os.path.abspath( __file__ ))):
  base_file, ext = os.path.splitext(filename)

  if ext == ".nc" and base_file.split('_')[0] == 'S5P':
    product_name = base_file + "_" + str(i)

    try:
        product_name = harp.import_product(base_file + ext,
                                            operations="latitude > 27.9 [degree_north]; latitude < 28.9 [degree_north]; "
                                                       "longitude > -17[degree_east]; longitude < -16[degree_east];"
                                                       "tropospheric_NO2_column_number_density_validity > 75;"
                                                       "bin_spatial(100, -17, 0.01, 100, 28.9, 0.01)",
                                            post_operations="bin();squash(time, (latitude,longitude))")

        products.append(product_name)
    except:
        print ("Error: Product not imported")

    i = i + 1

try:
    product_bin = harp.execute_operations(products, "", "bin()")
    harp.export_product(product_bin, str(nombre_nc)+".nc")

except:
    print("Error: Execute operations fail")

```

When I plot it with Panoply absolutely nothing is showing:

 ![image](https://forum.atmospherictoolbox.org/uploads/default/original/1X/c8f32b7cacaa7621aef8179b6e126de177d8420d.png)

I am new to using this type of tools and I don’t understand what could be going wrong.

I really would appreciate your help

Sincerely,  
Sara.

---

<div class="post-metadata">

### Author: ![sander.niemeijer](https://forum.atmospherictoolbox.org/user_avatar/forum.atmospherictoolbox.org/sander.niemeijer/32/5_2.png) [@sander.niemeijer](https://forum.atmospherictoolbox.org/u/sander.niemeijer)
#### Post date: [July 22, 2021, 12:49pm UTC](https://forum.atmospherictoolbox.org/t/harp-and-process-nc-files-of-sentinel-5p/372/2 "2021-07-22T12:49:44Z")

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Which product(s) have you used as input?  
You have a very small area, and it could be that there were no ‘valid’ pixels for that area (i.e. validity\>75).