topic Re: Dateformat in Data Management Questions

Dateformat

A_n_d_r_e_a — Tue, 13 Apr 2021 16:48:34 GMT

Dear Community,

i want to use Python to create a new date format.

I have found something on the website:

datetime.datetime(2000, 12, 31)

!field1! + datetime.timedelta(days=100)

I want to try it with the both.

Does anybody know, where i should add it in the field calculator.

In the code block?

Sorry for my little informatic knowledge...

Greetings,

Andrea

Re: Dateformat

DavidPike — Tue, 13 Apr 2021 18:02:50 GMT

You could add it in the code block as a function, but it should work just fine in the normal window (just above the code block space).

You do already have a field where you're adding the 100 days to? I'm not sure what you mean by 'new date format', and what is the 31 Dec 2000 for?

If you just want to play with the module, use an IDE or online compiler such as Online Python Compiler (Interpreter) (programiz.com)

then try things such as:

import datetime initial_datetime = datetime.datetime(2000, 12, 31) time_delta = datetime.timedelta(days=100) print(initial_datetime) print(initial_datetime + time_delta)

Re: Dateformat

A_n_d_r_e_a — Tue, 13 Apr 2021 19:49:38 GMT

Hi David,

my mean Problem starts by the default time setting in ArcGIS.

If i import my netCDF than the date is imported incorrect such as double. If i create a new field in a date format, the date begins just as by default 1899 and not like my original 2019.

So i want to calculate a new field to get to my original date which is 2019-01-01 to 2020-12-31.

That 31.Dec 2000 was just an example...

Re: Dateformat

A_n_d_r_e_a — Tue, 13 Apr 2021 20:52:00 GMT

...as you can see in the picture the imported netCDF and the date or "time" is shown up as double, i calculated a new field "Date" in date format with the time field, and its still not 2019...its still no the original date...

Thanks forward!

Greetings,

Andrea

Re: Dateformat

DavidPike — Tue, 13 Apr 2021 20:57:14 GMT

you should just be able to specify an exact date for all the rows in the correct format, such as

2019-01-01 00:00:00

However I can't really comment on NetCDF as I believe the temporal dimension is stored differently.

Hopefully there's some examples with the Make NetCDF Raster Layer tool and the dimension parameter.

Re: Dateformat

DavidPike — Wed, 14 Apr 2021 14:31:58 GMT

From your explanations I still have no idea what you want to do sorry, hopefully someone else can help.

Re: Dateformat

A_n_d_r_e_a — Wed, 14 Apr 2021 15:20:37 GMT

Hi David,

the thing is I choose from a satellite website some Data in netCDF Format. An I set the beginning of my time period on 2019-01-01. But instead of that it is shown up as a double value like you can see in the picture with a red border. And i want to have it like 2019-01-01. I uploaded a picture with my Problem.

Thanks forward!

Greetings,

Andrea

Re: Dateformat

DanPatterson — Wed, 14 Apr 2021 17:10:08 GMT

If your time column is "days" then read on

d = datetime.datetime(2019, 1, 1) # your initial date at the top d datetime.datetime(2019, 1, 1, 0, 0) time_vals = [46, 47, 48, 49] # -- using some of the values I saw in the "time" column # ---- now pretend this is a field calculation # ---- look at the output, this is what would appear as you go down the column for val in time_vals: new_date = d + datetime.timedelta(days = val) print(new_date) 2019-02-16 00:00:00 2019-02-17 00:00:00 2019-02-18 00:00:00 2019-02-19 00:00:00

I think the field calculator expression would be

datetime.datetime(2019, 1, 1) + datetime.timedelta(days = !time!)

Re: Dateformat

A_n_d_r_e_a — Wed, 14 Apr 2021 23:29:29 GMT

Hey Dan,

many thanks for your effort.

That is also an options to calculat an field, but I think I found my solution for my multidimensional data.

I would ask you to check my solution.

I found my solution in the link on the page of ArcGIS...

https://desktop.arcgis.com/en/arcmap/10.3/manage-data/raster-and-images/wkfl-create-a-multidimensional-mosaic-dataset-from-a-set-of-time-series-images.htm

So i create a Variable Field, a Dimension Field with "StdTime". Now there is also a little Problem with understanding Python...

I uploaded a picture with a red mark, which doesnt fit to my date I think...if i put this inside the Code Block and click ok, its written there something with invalid parameter? So the date should retrieved but how which syntax?

Thanks forward!

Greetings,

Andrea

Re: Dateformat

DanPatterson — Wed, 14 Apr 2021 23:40:32 GMT

The codeblock isn't properly formatted in the link.

def getDate(name): year = name[18:22] month = name[23:25] return time.strftime("/".join(["1", month, year]))

Now in your expression you have ....!Name! is that the name of the field? If not replace it with the name of the field you want to use

Also you might want to check or provide a sample of your field because the slicing needs to be checked (eg name[18:22]

Re: Dateformat

A_n_d_r_e_a — Thu, 15 Apr 2021 20:52:02 GMT

Hey Dan,

you know, the Name is the Name of the field with the NO2 concentration. The last sentence i don`t understand. Please can you explain it a little bit more? What is (eg name[18:22]?

Greetings,

Andrea

Re: Dateformat

DanPatterson — Thu, 15 Apr 2021 22:18:53 GMT

for the script to work the field has to contain the date information in it.

I don't see that in your "name" field.

There are no numbers that represent the year or month.

I can't work off screen grabs of information to copy and paste to provide an example.

Nothing so far has helped. Unless you have what is needed by the function, I have nothing further to add.

Re: Dateformat

A_n_d_r_e_a — Fri, 16 Apr 2021 16:10:22 GMT

Hey Dan,

ok now I get you. But what I don`t understand is...

year = name[18:22]

month = name[23:25]

what does these numbers mean?

I can`t read it in the link.

Thanks forward!

Greetings,

Andrea

Re: Dateformat

DanPatterson — Fri, 16 Apr 2021 18:17:20 GMT

the 18 to 22 characters in "name" are the year

the 23 to 25 characters in "name" are the month

Re: Dateformat

A_n_d_r_e_a — Fri, 16 Apr 2021 20:09:04 GMT

Hey Dan,

thanks for the info...I just uploaded a picture. There you can see the Datum field an StdTime which I create. Both in Date format. On the right side there you can see the def getDate(Datum):

def getDate(Datum):
year = Datum[18:22]
month = Datum[23:25]
return time.strftime("/".join(["1", month, year]))

Is that right like this? Than there is also still the Problem to convert it to my orginial time from 2019-2020.

Thanks forward!

Greetings,

Andrea

Re: Dateformat

DavidPike — Fri, 16 Apr 2021 20:55:50 GMT

have you tried the script Dan provided? it looks like it would work exactly as needed using your day integer values.

Re: Dateformat

A_n_d_r_e_a — Sun, 18 Apr 2021 11:54:29 GMT

Your "days" column in which type has it to be?

Re: Dateformat

A_n_d_r_e_a — Mon, 19 Apr 2021 00:07:41 GMT

I just realized now that my date field is a double type, so it should be possible to use the toolbox "convert time field". I just opened the netCDF data with Panoply and the data is there in a 20190101 format and its written there als float type. Does that help? Of course I also have to keep attention to the locale. So I need a formate where I can use also with the time controller. So the best format would be JJJJ/MM/TT hh:mm:ss because I have data for every hour.

Here is the link where I get the information...

https://desktop.arcgis.com/de/arcmap/latest/map/time/convert-string-or-numeric-time-values-into-date-format.htm

https://pro.arcgis.com/de/pro-app/latest/help/mapping/time/supported-field-formats.htm

Thanks forward!

Greetings,

Andrea

Re: Dateformat

A_n_d_r_e_a — Sat, 24 Apr 2021 14:58:12 GMT

Hi Dan,

can you please complete this script with a 24 hours loop? I searched everywhere for that but I can`t find...

So just like

2019-01-01 00:00:00

2019-01-01 01:00:00

2019-01-01 02:00:00

...and so on

End date should be 2020-12-31 23:00:00

Thanks,

Regards,

Andrea