Magnetic delcination not displaying

[seabilwe]

The parameters of the MD script were updated based on the query reported in the Map Downloader WhatsApp group. However, when testing the updated script on a local QGIS topo project, the MD is not displaying, and the preview values are showing as NULL.

Here is the updated script:

import json
from datetime import datetime
from urllib import parse, request
from urllib.error import HTTPError
from math import floor
import ssl
from qgis.core import QgsMessageLog, Qgis, QgsExpression, QgsGeometry, QgsRectangle
from qgis.utils import qgsfunction

def json_response(url):
    try:
        data = request.urlopen(url)
        error_code = data.getcode()
    except HTTPError as error:
        error_code = error.code
    if error_code == 200:
        response = data.read()
        response_text = response.decode('utf-8')
    else:
        response_text = None
    return response_text


def dd2dms(decimal_degree):
    if type(decimal_degree) != 'float':
        try:
            decimal_degree = float(decimal_degree)
        except:
            print('\nERROR: Could not convert %s to float.' % (type(decimal_degree)))
            return 0
    if decimal_degree < 0:
        decimal_degree = -decimal_degree
        appendix = 'W'
    else:
        appendix = 'E'
    minutes = decimal_degree % 1.0 * 60
    seconds = minutes % 1.0 * 60
    format_degree = int(floor(decimal_degree))
    format_minutes = int(floor(minutes))
    format_seconds = round(seconds, 2)
    return format_degree, format_minutes, format_seconds, appendix


@qgsfunction(args='auto', group='Kartoza')
def map_decl(center_lat, center_long, feature, parent):
    """
    Calculates the magnetic declination of the map centroid.
    <h2>Example usage:</h2>
    <ul>
      <li>map_decl(x(map_get( item_variables('Ortho'), 'map_extent_center')),y(map_get( item_variables('Ortho'), 'map_extent_center'))) </li>
      <li>map_decl('lat_centroid_function','long_centroid_function') </li>
    </ul>
    """
    ssl._create_default_https_context = ssl._create_unverified_context
    now = datetime.now()
    month = now.month
    month_day = now.day
    mag_model = 'IGRF'
    mag_component = 'd'
    params = parse.urlencode({
        'lat1': abs(center_lat), 
        'lon1': abs(center_long), 
        'startDay': month_day, 
        'model': mag_model, 
        'magneticComponent': mag_component, 
        'resultFormat': 'json', 
        'startMonth': month
    })
    mag_url = f"http://www.ngdc.noaa.gov/geomag-web/calculators/calculateDeclination?{params}"
    mag_response_text = json_response(mag_url)
    
    # Debugging line to print the API response
    print(f"API Response: {mag_response_text}")
    
    if mag_response_text is not None:
        try:
            mag_response_json = json.loads(mag_response_text)["result"][0]
        except json.decoder.JSONDecodeError:
            print("There was a problem accessing NOAA Magnetic Declination calculators.")
            formatted_label = 'NOAA Magnetic Declination unavailable'
        else:
            magnetic_declination = mag_response_json["declination"]
            annual_change = mag_response_json["declnation_sv"]
            dms_magnetic_decl = dd2dms(round(magnetic_declination, 4))
            dms_annual_change = dd2dms(round(annual_change, 4))
            mag_declination_value = f" {dms_magnetic_decl[0]}° {dms_magnetic_decl[1]}' {dms_magnetic_decl[3]}"
            mean_annual_change_value = f" {dms_annual_change[0]}° {dms_annual_change[1]}' {dms_annual_change[3]}"
            formatted_label = f'Mean magnetic declination {mag_declination_value} \nMean annual change {mean_annual_change_value} per year'
    else:
        formatted_label = None
    return formatted_label

cc @gubuntu

[gubuntu]

this and other scripts should be in the code repo (one of these two? https://github.com/search?q=repo%3Akartoza%2FSAGTA%20geomag&type=code), not in the issue itself. This is not how you update and merge code changes

[seabilwe]

The md is displaying again:

changes have been made to the magnetic_declination.py and the init.py

@tharanathkartoza please assist with applying these changes

[dimasciput]

PR for this ticket : #86

[dimasciput]

1aeffb3