Error: Plot latitude grid should be the same

VISAN
1

Dear,
I’m developing a python script in order to obtain a 7 days average of NO2 values from Sentinel 5p and then dinamically visualize the change over a period of time (5 months). So I merge this 7 days average results keeping the time variable.

It works (apparently) but when I try to visualize the result into VISAN using wplot(product), I get this error:
ValueError: plot latitudeGrid should be the same for all grids

What’s strange is that depending of the products I merge, I don’t get this error.

Could someone help me?

Thanks in advance,

Josep

2

You probably need to explain a bit more what you are doing exactly to generate your ‘product’ variable.
The error you are getting happens if your latitude axis variable is 2 dimensional (time,latitude) and the latitude grid is not the same for different times.
It is recommended to perform a squash(time,(latitude,longitude)) as a final operation to remove the time dimension of your lat/lon axis variables.

3

Dear Sander,

first of all I import the products into harp in that way:

product_name = harp.import_product(base_file + ext,
operations=“latitude > -55 [degree_north]; latitude < 60 [degree_north]; tropospheric_NO2_column_number_density_validity > 75;bin_spatial(271,-55,0.5,721,-180,0.5)”,
post_operations=“bin();squash(time, (latitude,longitude))”)

This happens inside a loop, and the variable product_name change every time.

The products from one week are stored into a list. And when the list is filled with 7 products, I merge them using:

product_bin = harp.execute_operations(products, “”, “bin()”)

And then I export the result of this merge into a NetCDF file.
harp.export_product(product_bin, str(nombre_nc)+".nc")

Finally, I merge the products from several weeks using the command line:

harpmerge week*.nc mosaic.nc

My idea is to visualize the evolution of the weekly NO average.

Thanks for your help.

Josep,

4

Try using:

harpmerge -ap 'squash(time,(latitude,longitude))' week*.nc mosaic.nc

5

Dear @svniemeijer,
thanks for your reply.

But if I execute this harpmerge command, I get this error:

ERROR: variable ‘latitude’ does not exist

6

Then what you have described above is not what you are actually doing.
You should still have latitude and longitude variables.

7

Thanks @svniemeijer,
I’ve made some changes, but now I get this error:
ERROR: variable ‘latitude’ does not have the same values in each subdimension block for squash operation

Do you know what can happen?

Thanks!

8

You probably did not create all files using the same bin_spatial() configuration.
You can’t mix grids with different lat/lon grids.

9

Hi @svniemeijer,
I used the same bin_spatial()
I don’t know what is the reason of this error.

10

Working with products from european region, do you think a bin_spatial like that is correct?

bin_spatial(271,-55,0.5,721,-180,0.5)

Thanks @svniemeijer