Replace the coeffs in IGRF-13. Now results after 2010 may be differen…

…t from IGRF-12. The last year that can be calculated extends to 2030.

README.md

@@ -1,6 +1,6 @@
 # pyIGRF
 ## What is pyIGRF?  
-This is a package of IGRF-12 (International Geomagnetic Reference Field) about python version. 
+This is a package of IGRF-13 (International Geomagnetic Reference Field) about python version. 
 We can calculate magnetic field intensity and transform coordinate between GeoGraphical and GeoMagnetic.
 It don't need any Fortran compiler. But it needs NumPy package.  
 
@@ -28,14 +28,14 @@ the response is 7 float number about magnetic filed which is:
 - F: total intensity  
 *unit: degree or nT*
 
-If you want to use IGRF-12 more flexibly, you can use module *calculate*. 
+If you want to use IGRF-13 more flexibly, you can use module *calculate*. 
 There is two function which is closer to Fortran. You can change it for different coordination.
 >```from pyIGRF import calculate```  
 
-Another module *loadCoeffs* can be used to get *g[m][n]* or *h[m][n]* same as that in formula.
->```from pyIGRF.loadCoeffs import getCoeffs``` 
+Another module *load_coeffs* can be used to get *g[m][n]* or *h[m][n]* same as that in formula.
+>```from pyIGRF.load_coeffs import get_coeffs``` 
 
 
 
-## Model Introduction and igrf12-coeffs File Download
+## Model Introduction and igrf13-coeffs File Download
 https://www.ngdc.noaa.gov/IAGA/vmod/igrf.html

pyIGRF/loadCoeffs.py

@@ -33,7 +33,7 @@ def load_coeffs(filename):
         return gh
 
 
-gh = load_coeffs(os.path.dirname(os.path.abspath(__file__)) + '/src/igrf12coeffs.txt')
+gh = load_coeffs(os.path.dirname(os.path.abspath(__file__)) + '/src/igrf13coeffs.txt')
 
 
 def get_coeffs(date):
@@ -42,17 +42,17 @@ def get_coeffs(date):
     :param date: float
     :return: list: g, list: h
     """
-    if date < 1900.0 or date > 2025.0:
+    if date < 1900.0 or date > 2030.0:
         print('This subroutine will not work with a date of ' + str(date))
-        print('Date must be in the range 1900.0 <= date <= 2025.0')
+        print('Date must be in the range 1900.0 <= date <= 2030.0')
         print('On return [], []')
         return [], []
-    elif date >= 2015.0:
-        if date > 2020.0:
+    elif date >= 2020.0:
+        if date > 2025.0:
             # not adapt for the model but can calculate
-            print('This version of the IGRF is intended for use up to 2020.0.')
+            print('This version of the IGRF is intended for use up to 2025.0.')
             print('values for ' + str(date) + ' will be computed but may be of reduced accuracy')
-        t = date - 2015.0
+        t = date - 2020.0
         tc = 1.0
         #     pointer for last coefficient in pen-ultimate set of MF coefficients...
         ll = 3060