# Color by datetime in plot **URL:** \ **Category:** PyGMT Q&A\ **Created:** [December 5, 2021, 4:06am UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409 "2021-12-05T04:06:09Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![FinniganIK](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/finniganik/32/1587_2.png) [@FinniganIK](https://forum.generic-mapping-tools.org/u/FinniganIK)\ **Post date:** [December 5, 2021, 4:06am UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/1 "2021-12-05T04:06:09Z")
I’m trying to use PyGMT to plot some earthquakes and color them by their origin time I have my earthquake catalogue in a Pandas dataframe and the origin time has been converted to a datetime object using: `catalogue['OriginTime'] = pd.to_datetime(catalogue['OriginTime'])` Then making a color pallete using: `pygmt.makecpt(cmap="hawaii", series=[pd.to_datetime("2015-03-03T00:00:00"),pd.to_datetime("2015-03-16T00:00:00"),1000])` Then try to plot using the color option as follows: `color=catalogue.loc['OriginTime']` However, this gives an error that I’m struggling to find a way around: `TypeError: sequence item 0: expected str instance, Timestamp found` I’ve tried converting the time output into a string using: `color=catalogue.loc['OriginTime'].dt.strftime('%Y-%m-%dT%H:%M:%S')` But that gives a similar error of: `TypeError: sequence item 1: expected str instance, float found` Any ideas? ---
**Author:** ![weiji14](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/weiji14/32/33_2.png) [@weiji14](https://forum.generic-mapping-tools.org/u/weiji14)\ **Post date:** [December 5, 2021, 10:48am UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/2 "2021-12-05T10:48:17Z")
Hmm, you might need to include the time unit in the `pygmt.makecpt` call. Try something like: ```python pygmt.makecpt( cmap="hawaii", series=[ pd.to_datetime("2015-03-03T00:00:00"), pd.to_datetime("2015-03-16T00:00:00"), "1d", ] ) ``` which would set an interval of 1 **d** ay. See [https://docs.generic-mapping-tools.org/6.2/makecpt.html#generate-1d-array](https://docs.generic-mapping-tools.org/6.2/makecpt.html#generate-1d-array) for more details (search for `TIME_UNIT`). If that doesn’t work, please provide the output of `print(df.head())` and your full `fig.plot` command (copy and paste the text please) so that we can see what’s going on. ---
**Author:** ![FinniganIK](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/finniganik/32/1587_2.png) [@FinniganIK](https://forum.generic-mapping-tools.org/u/FinniganIK)\ **Post date:** [December 5, 2021, 7:36pm UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/3 "2021-12-05T19:36:02Z")
No luck with that I’m afraid, here is df.head(): ``` EventID OriginTime ... Magnitude LocationID 0 3217336 2010-01-02 00:58:29.292000+00:00 ... 1.216068 GC 3 3217337 2010-01-02 01:00:50.389000+00:00 ... 1.331515 GC 4 3217344 2010-01-02 01:13:24.555000+00:00 ... 1.344449 GC 5 3217354 2010-01-02 01:34:42.618000+00:00 ... 1.252554 GC 10 2010d000006 2010-01-05 05:28:19.244000+00:00 ... 1.087038 GC [5 rows x 9 columns] ``` and here is the full fig.plot command: ``` pygmt.makecpt(cmap="hawaii", series=[pd.to_datetime("2015-03-03T00:00:00"),pd.to_datetime("2015-03-16T00:00:00"),"1d"]) fig.plot(x=df['Longitude'], y=df['Latitude'], size=df['Magnitude']/7, color=df['OriginTime'].dt.strftime('%Y-%m-%dT%H:%M:%S'), style="cc", pen="black", cmap=True) ``` ---
**Author:** ![weiji14](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/weiji14/32/33_2.png) [@weiji14](https://forum.generic-mapping-tools.org/u/weiji14)\ **Post date:** [December 6, 2021, 12:03am UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/4 "2021-12-06T00:03:37Z")
Right, so the `.dt.strftime` is not necessary, it’s actually better to keep preserve the ‘OriginTime’ column in a `np.datetime64` dtype because PyGMT can pass that data column to GMT using `GMT_DATETIME` (don’t worry if that doesn’t make sense). Here’s some sample code (I had to make up some dummy data for some columns): ```python import numpy as np import pandas as pd import pygmt df = pd.DataFrame( data=dict( OriginTime=[ np.datetime64("2010-01-02 00:58:29.292000"), np.datetime64("2010-01-02 01:00:50.389000"), np.datetime64("2010-01-02 01:13:24.555000"), np.datetime64("2010-01-02 01:34:42.618000"), np.datetime64("2010-01-05 05:28:19.244000"), ], Magnitude=[1.216068, 1.331515, 1.344449, 1.252554, 1.087038], Longitude=[1, 2, 3, 4, 5], Latitude=[6, 7, 8, 9, 10], ) ) # %% fig = pygmt.Figure() pygmt.makecpt( cmap="hawaii", series=[ pd.to_datetime("2010-01-01T00:00:00"), pd.to_datetime("2010-01-05T00:00:00"), "1d", ], ) fig.plot( x=df["Longitude"], y=df["Latitude"], size=df["Magnitude"] / 7, color=df["OriginTime"], style="cc", pen="black", cmap=True, frame=True, # coltypes="i2T", ) fig.colorbar() fig.savefig("datetime_points.png") fig.show() ``` produces: ![datetime_points](https://canada1.discourse-cdn.com/flex047/uploads/gmt/original/2X/d/d1860ada97b8f243a63893ad06b9b1cea7e90f26.png) There’s also a related forum thread at [https://flint.soest.hawaii.edu/t/pygmt-pygmt-makecpt-with-dates-times/2141](https://flint.soest.hawaii.edu/t/pygmt-pygmt-makecpt-with-dates-times/2141) which you might find helpful. The `coltypes` parameter should not be needed, unless you pass in the time column as a `str` dtype, but it’s good to know in case you want to pass in a plaintext data file or something. Oh, and I’m not quite sure how to get the colorbar to display the actual dates rather than the UNIX format time. Might need to ask another GMT guru for help on this. ---
**Author:** ![ecastillot](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/ecastillot/32/1281_2.png) [@ecastillot](https://forum.generic-mapping-tools.org/u/ecastillot)\ **Post date:** [April 7, 2022, 2:33pm UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/5 "2022-04-07T14:33:29Z")
Did you find any way to display the colorbar with the actual dates? Could you tell me how I do it. Thanks. ---
**Author:** ![ecastillot](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/ecastillot/32/1281_2.png) [@ecastillot](https://forum.generic-mapping-tools.org/u/ecastillot)\ **Post date:** [April 7, 2022, 2:54pm UTC](https://forum.generic-mapping-tools.org/t/color-by-datetime-in-plot/2409/6 "2022-04-07T14:54:52Z")
I found it. cb = fig.colorbar(frame=“af”) > [@ecastillot](#): > > Did you find any way to display the colorbar with the actual dates? > > Could you tell me how I do it. > > Thanks.