Extracting data from a web page

Hi, I would like to automatize the extraction of data from different events and I would like some help on how extract the numerical data from this webpage: M 7.2 - 8 km W of Atiquipa, Peru (usgs.gov) like these:

W-phase Moment Tensor (Mww)

Moment:6.955e+19 N-m

Magnitude:7.16 Mww

Depth:17.5 km

Percent DC:96%

Half Duration:8.50 s

Catalog:US

Data Source:US 3

Contributor:US 3

Nodal Planes

NP1

Strike:309°

Dip: 16°

Rake: 57°

NP2

Strike: 164°

Dip:77°

Rake:99°

Principal AxesAxisValuePlungeAzimuthT6.893e+1957°86°N0.123e+199°342°P-7.016e+1931°246°

Principal Axes

T:6.893e+19,57°,86°

N:0.123e+19,9°,342°

P:-7.016e+19,31°,246°

I would appreciate the help

Answer 1

[Umar]

Hi Jorge,

You can use Matlab's web scraping capabilities along with regular expressions to extract the desired numerical data. Here is a sample code snippet that demonstrates how to extract the Moment value from the provided webpage:

% URL of the webpage

url = 'https://earthquake.usgs.gov/earthquakes/eventpage/us7000e7y0/executive';

% Read the webpage content

webpage = webread(url);

% Extract Moment value using regular expressions

moment_pattern = 'Moment:(\d+\.\d+e[+-]\d+) N-m';

moment_match = regexp(webpage, moment_pattern, 'tokens', 'once');

% Display the extracted Moment value

if ~isempty(moment_match)

    moment_value = str2double(moment_match{1});

    disp(['Extracted Moment Value: ', num2str(moment_value)]);

else

    disp('Moment value not found.');

end

Hope that answers your question.

[Jorge Luis]

Hi, thank you for your response. The problem is that the variables are not captured as they are when using the webread function.

[Umar]

Hi Jorge,

When dealing with variables not being captured correctly in the webread function in Matlab, ensure that the URL is properly formatted and that the variables are appropriately encoded. You can use the weboptions function to set parameters like 'MediaType' and 'RequestMethod' to handle different types of data. Additionally, consider encoding the variables using functions like urlencode to prevent any issues with special characters. By adjusting these settings and encoding the variables correctly, you can enhance the accuracy of capturing variables when using the webread function in Matlab.

Let me know if you need further assistance, I will be happy to help.