This week's tip and trick is about using Python to generate a series of images from a map. It's also a bit more technical than the earlier #MapInfoMonday Tips & Tricks.
There are multiple scenarios where you want to create multiple versions of the "same" map. You might have multiple locations, you want to be printed, maybe you want to see the same location but slowly zooming into the location from a larger area, and then there is this scenario where you want to show values for one location as they change over time.
I have downloaded the Covid-19 data
from Johns Hopkins University via the Github repository they have setup. This gives you access to a number of CSV files with data from all over the World as current status or as time series where you get all the numbers since early March.
In my case, I'm using data from early March into Mid-April. You can of course extend this to go all the way up to the most recent dataset. I'm focusing on the United States but you could also have chosen the entire World as that data also is available.
I have opened the CSV file into MapInfo Pro, created points using the Lat/Long values in the data, added the data to a map where I also have the Precisely Iron map, and I have made the Covid-19 data layer invisible. My script will add a thematic layer to the map using data for each of the days which is why I don't need to display the actual data points from the beginning.
Below you can see how my map looks, and you can also see the Python script in the Python console window at the bottom.
Let me take you through the script in some smaller steps.
I'm using the
print statement to write a bit of text to the Message window and specifying the table to be used in the loop later on.
print("Starting now")sTab = 'time_series_covid19_deaths_US'Next, I need to specify the columns to loop through and a more friendly name to be used for the files generated. For this, I'm creating a list containing multiple lists. The inner lists hold two elements; the column name and the friendly name.
themeColumns = [ ['_4_14_20', '2020-04-14'], ['_4_13_20', '2020-04-13'], ['_4_12_20', '2020-04-12'] , ['_4_11_20', '2020-04-11'], ['_4_10_20', '2020-04-10'], ['_4_9_20', '2020-04-09'] , ['_4_8_20', '2020-04-08'], ['_4_7_20', '2020-04-07'], ['_4_6_20', '2020-04-06'] , ['_4_5_20', '2020-04-05'], ['_4_4_20', '2020-04-04'], ['_4_3_20', '2020-04-03'] , ['_4_2_20', '2020-04-02'], ['_4_1_20', '2020-04-01'], ['_3_31_20', '2020-03-31'] , ['_3_30_20', '2020-03-30'], ['_3_29_20', '2020-03-29'], ['_3_28_20', '2020-03-28'] , ['_3_27_20', '2020-03-27'], ['_3_26_20', '2020-03-26'], ['_3_25_20', '2020-03-25'] , ['_3_24_20', '2020-03-24'], ['_3_23_20', '2020-03-23'], ['_3_22_20', '2020-03-22'] , ['_3_21_20', '2020-03-21'], ['_3_20_20', '2020-03-20'], ['_3_19_20', '2020-03-19'] , ['_3_18_20', '2020-03-18'], ['_3_17_20', '2020-03-17'], ['_3_16_20', '2020-03-16'] , ['_3_15_20', '2020-03-15'], ['_3_14_20', '2020-03-14'], ['_3_13_20', '2020-03-13'] , ['_3_12_20', '2020-03-12'], ['_3_11_20', '2020-03-11'], ['_3_10_20', '2020-03-10'] , ['_3_9_20', '2020-03-09'], ['_3_8_20', '2020-03-08'], ['_3_7_20', '2020-03-07'] , ['_3_6_20', '2020-03-06'], ['_3_5_20', '2020-03-05'], ['_3_4_20', '2020-03-04'] , ['_3_3_20', '2020-03-03'], ['_3_2_20', '2020-03-02'], ['_3_1_20','2020-03-01']]Now it's time to do the actual loop where I run through all the lists in the list
themeColumns. I get the two values from the individual elements of the list, use the
do method to pass a Shade statement to MapInfo Pro, create a friendly file name using the nicely formatted date, and then I use another two
do statements; one to export the window into a PNG file and the other to remove the thematic layer from the map window.
for theme in themeColumns: col = theme[0] date = theme[1] do('shade window FrontWindow() 1 with {} ignore 0 graduated 0.0:0 10000:24 Symbol (35,12583104,36,"MapInfo Symbols",0,0) Symbol (35,255,36,"MapInfo Symbols",0,0) vary size by "LOG"'.format(col)) fileName = r'D:\3. Demo\2. Maps\2020\Covid19\04-14 Data April 14\Time Series\US {}.PNG'.format(date) do('Save Window FrontWindow() As "{}" Type "PNG" Resolution 300'.format(fileName)) do('Remove Map Window FrontWindow() Layer 1')And finally, I use another print statement to write the word Finished to the Message window.
print('Finished')I have attached the full source code as a text file below.
A single exported image looks like this
And if you create a GIF from all the files, it can look like this
You can do a lot using a few lines of Python code. Python is one of the most used development languages and we are glad to also be able to give MapInfo Pro users access to using Python as an alternative to and in combination with MapBasic. When you are using the Python Console instead of the MapBasic Window, you get at least two major benefits besides the Python language itself: You can use loops, as I just showed above, and you can also use If statements. These two alone make it way more powerful compared to the MapBasic Window.
I hope you found this tip useful. If you have any questions, or ideas for next week's #MapInfoMonday tip and trick, use the Comments section below.
#MapInfoMonday is your weekly little tip to help you get more from your MapInfo Pro.------------------------------
Peter Horsbøll Møller
Principal Presales Consultant | Distinguished Engineer
Precisely | Trust in Data
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