diff --git a/docs/source/conf.py b/docs/source/conf.py
index f197f626..e1a99a2a 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 #
 # GeoStatTools documentation build configuration file, created by
 # sphinx-quickstart on Fri Jan  5 14:20:43 2018.
@@ -111,7 +110,7 @@ def setup(app):
 # General information about the project.
 curr_year = datetime.datetime.now().year
 project = "GSTools"
-copyright = "2018 - {}, Sebastian Müller, Lennart Schüler".format(curr_year)
+copyright = f"2018 - {curr_year}, Sebastian Müller, Lennart Schüler"
 author = "Sebastian Müller, Lennart Schüler"
 
 # The version info for the project you're documenting, acts as replacement for
diff --git a/examples/00_misc/02_check_rand_meth_sampling.py b/examples/00_misc/02_check_rand_meth_sampling.py
index dfbfd741..0b23a929 100644
--- a/examples/00_misc/02_check_rand_meth_sampling.py
+++ b/examples/00_misc/02_check_rand_meth_sampling.py
@@ -57,7 +57,7 @@ def plot_rand_meth_samples(generator):
     sample_in = np.sum(rad <= np.max(x))
     ax.hist(rad[rad <= np.max(x)], bins=sample_in // 50, density=True)
     ax.set_xlim([0, np.max(x)])
-    ax.set_title("Radius samples shown {}/{}".format(sample_in, len(rad)))
+    ax.set_title(f"Radius samples shown {sample_in}/{len(rad)}")
     ax.legend()
     plt.show()
 
diff --git a/examples/01_random_field/00_gaussian.py b/examples/01_random_field/00_gaussian.py
index 726ad653..b7bde5f9 100644
--- a/examples/01_random_field/00_gaussian.py
+++ b/examples/01_random_field/00_gaussian.py
@@ -1,4 +1,4 @@
-"""
+r"""
 A Very Simple Example
 ---------------------
 
diff --git a/examples/01_random_field/05_mesh_ensemble.py b/examples/01_random_field/05_mesh_ensemble.py
index 8ff13e4b..1e2f0da8 100755
--- a/examples/01_random_field/05_mesh_ensemble.py
+++ b/examples/01_random_field/05_mesh_ensemble.py
@@ -46,13 +46,13 @@
 # You can specify the field name by the keyword `name`.
 
 for i in range(fields_no):
-    srf.mesh(mesh, points="centroids", name="c-field-{}".format(i), seed=i)
+    srf.mesh(mesh, points="centroids", name=f"c-field-{i}", seed=i)
 
 ###############################################################################
 # Now we generate fields on the mesh-points again controlled by a seed.
 
 for i in range(fields_no):
-    srf.mesh(mesh, points="points", name="p-field-{}".format(i), seed=i)
+    srf.mesh(mesh, points="points", name=f"p-field-{i}", seed=i)
 
 ###############################################################################
 # To get an impression we now want to plot the generated fields.
diff --git a/setup.py b/setup.py
index 4dd06ad7..30fc704b 100644
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """GSTools: A geostatistical toolbox."""
 import os
 
diff --git a/src/gstools/__init__.py b/src/gstools/__init__.py
index 970574ff..6f5a2034 100644
--- a/src/gstools/__init__.py
+++ b/src/gstools/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 Purpose
 =======
diff --git a/src/gstools/config.py b/src/gstools/config.py
index 38f3e7fa..30ac4554 100644
--- a/src/gstools/config.py
+++ b/src/gstools/config.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing global variables.
 
diff --git a/src/gstools/covmodel/__init__.py b/src/gstools/covmodel/__init__.py
index 38414a48..0c61d404 100644
--- a/src/gstools/covmodel/__init__.py
+++ b/src/gstools/covmodel/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a set of handy covariance models.
 
diff --git a/src/gstools/covmodel/base.py b/src/gstools/covmodel/base.py
index 2e366f94..686768fa 100644
--- a/src/gstools/covmodel/base.py
+++ b/src/gstools/covmodel/base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing the base class for covariance models.
 
diff --git a/src/gstools/covmodel/fit.py b/src/gstools/covmodel/fit.py
index b50dad94..2ff5398b 100755
--- a/src/gstools/covmodel/fit.py
+++ b/src/gstools/covmodel/fit.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for the covariance-model.
 
diff --git a/src/gstools/covmodel/models.py b/src/gstools/covmodel/models.py
index 61243486..a2aaf6a3 100644
--- a/src/gstools/covmodel/models.py
+++ b/src/gstools/covmodel/models.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing different covariance models.
 
diff --git a/src/gstools/covmodel/plot.py b/src/gstools/covmodel/plot.py
index 574e0e20..e6453a8d 100644
--- a/src/gstools/covmodel/plot.py
+++ b/src/gstools/covmodel/plot.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing plotting routines for the covariance models.
 
diff --git a/src/gstools/covmodel/tools.py b/src/gstools/covmodel/tools.py
index cfc58636..98ed3b8a 100644
--- a/src/gstools/covmodel/tools.py
+++ b/src/gstools/covmodel/tools.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for the covariance-model.
 
diff --git a/src/gstools/covmodel/tpl_models.py b/src/gstools/covmodel/tpl_models.py
index c173d006..5e980760 100644
--- a/src/gstools/covmodel/tpl_models.py
+++ b/src/gstools/covmodel/tpl_models.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing truncated power law covariance models.
 
diff --git a/src/gstools/field/__init__.py b/src/gstools/field/__init__.py
index aa51bef4..65718bc7 100644
--- a/src/gstools/field/__init__.py
+++ b/src/gstools/field/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for spatial random fields.
 
diff --git a/src/gstools/field/base.py b/src/gstools/field/base.py
index 48fe7e25..903f3893 100755
--- a/src/gstools/field/base.py
+++ b/src/gstools/field/base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a base class for spatial fields.
 
diff --git a/src/gstools/field/cond_srf.py b/src/gstools/field/cond_srf.py
index 70ef6cc6..385216ba 100644
--- a/src/gstools/field/cond_srf.py
+++ b/src/gstools/field/cond_srf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a class for conditioned spatial random fields.
 
diff --git a/src/gstools/field/generator.py b/src/gstools/field/generator.py
index c2de58ff..4e171950 100644
--- a/src/gstools/field/generator.py
+++ b/src/gstools/field/generator.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing generators for spatial random fields.
 
diff --git a/src/gstools/field/plot.py b/src/gstools/field/plot.py
index 009d901d..528cdcc3 100644
--- a/src/gstools/field/plot.py
+++ b/src/gstools/field/plot.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing plotting routines for spatial fields.
 
diff --git a/src/gstools/field/srf.py b/src/gstools/field/srf.py
index 06839779..a8a1e575 100644
--- a/src/gstools/field/srf.py
+++ b/src/gstools/field/srf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a class for standard spatial random fields.
 
diff --git a/src/gstools/field/summator.pyx b/src/gstools/field/summator.pyx
index ecd7ea58..cad20e1d 100644
--- a/src/gstools/field/summator.pyx
+++ b/src/gstools/field/summator.pyx
@@ -1,5 +1,4 @@
 #cython: language_level=3, boundscheck=False, wraparound=False, cdivision=True
-# -*- coding: utf-8 -*-
 """
 This is the randomization method summator, implemented in cython.
 """
diff --git a/src/gstools/field/tools.py b/src/gstools/field/tools.py
index 019f2e58..4b128d8a 100644
--- a/src/gstools/field/tools.py
+++ b/src/gstools/field/tools.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for Fields.
 
diff --git a/src/gstools/field/upscaling.py b/src/gstools/field/upscaling.py
index cf77892d..ac5f49a9 100644
--- a/src/gstools/field/upscaling.py
+++ b/src/gstools/field/upscaling.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing upscaling routines for the spatial random field.
 
diff --git a/src/gstools/krige/__init__.py b/src/gstools/krige/__init__.py
index cc2436cd..9bb17fae 100644
--- a/src/gstools/krige/__init__.py
+++ b/src/gstools/krige/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing kriging.
 
diff --git a/src/gstools/krige/base.py b/src/gstools/krige/base.py
index e48c8fcc..77c6832e 100755
--- a/src/gstools/krige/base.py
+++ b/src/gstools/krige/base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a base class for kriging.
 
diff --git a/src/gstools/krige/krigesum.pyx b/src/gstools/krige/krigesum.pyx
index 41911cef..de3a43b1 100644
--- a/src/gstools/krige/krigesum.pyx
+++ b/src/gstools/krige/krigesum.pyx
@@ -1,5 +1,4 @@
 #cython: language_level=3, boundscheck=False, wraparound=False, cdivision=True
-# -*- coding: utf-8 -*-
 """
 This is a summator for the kriging routines
 """
diff --git a/src/gstools/krige/methods.py b/src/gstools/krige/methods.py
index 280e6811..653785f8 100644
--- a/src/gstools/krige/methods.py
+++ b/src/gstools/krige/methods.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing a class for simple kriging.
 
diff --git a/src/gstools/krige/tools.py b/src/gstools/krige/tools.py
index 183b918f..e3112ae4 100644
--- a/src/gstools/krige/tools.py
+++ b/src/gstools/krige/tools.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for Kriging.
 
diff --git a/src/gstools/normalizer/__init__.py b/src/gstools/normalizer/__init__.py
index f76a490f..24933fc7 100644
--- a/src/gstools/normalizer/__init__.py
+++ b/src/gstools/normalizer/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing normalization routines.
 
diff --git a/src/gstools/normalizer/base.py b/src/gstools/normalizer/base.py
index e8bb0a50..0072d6a9 100644
--- a/src/gstools/normalizer/base.py
+++ b/src/gstools/normalizer/base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing the base class for normalizers.
 
diff --git a/src/gstools/normalizer/methods.py b/src/gstools/normalizer/methods.py
index 3776ba1f..f66cfd19 100644
--- a/src/gstools/normalizer/methods.py
+++ b/src/gstools/normalizer/methods.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing different normalizer transformations.
 
diff --git a/src/gstools/normalizer/tools.py b/src/gstools/normalizer/tools.py
index 2d28bef9..7a5237b7 100644
--- a/src/gstools/normalizer/tools.py
+++ b/src/gstools/normalizer/tools.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for Normalizers.
 
diff --git a/src/gstools/random/__init__.py b/src/gstools/random/__init__.py
index 6c02da31..20fd9c45 100644
--- a/src/gstools/random/__init__.py
+++ b/src/gstools/random/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage for random number generation.
 
diff --git a/src/gstools/random/rng.py b/src/gstools/random/rng.py
index 11caad84..4f698557 100644
--- a/src/gstools/random/rng.py
+++ b/src/gstools/random/rng.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing the core of the spatial random field generation.
 
diff --git a/src/gstools/random/tools.py b/src/gstools/random/tools.py
index 831b1f6a..d61327ea 100644
--- a/src/gstools/random/tools.py
+++ b/src/gstools/random/tools.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for random sampling.
 
diff --git a/src/gstools/tools/__init__.py b/src/gstools/tools/__init__.py
index 730026cf..18892557 100644
--- a/src/gstools/tools/__init__.py
+++ b/src/gstools/tools/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing miscellaneous tools.
 
diff --git a/src/gstools/tools/export.py b/src/gstools/tools/export.py
index af6f61bd..3e522c92 100644
--- a/src/gstools/tools/export.py
+++ b/src/gstools/tools/export.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing export routines.
 
diff --git a/src/gstools/tools/geometric.py b/src/gstools/tools/geometric.py
index 84311447..afdcacaf 100644
--- a/src/gstools/tools/geometric.py
+++ b/src/gstools/tools/geometric.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing geometric tools.
 
diff --git a/src/gstools/tools/misc.py b/src/gstools/tools/misc.py
index 301da075..068200b7 100755
--- a/src/gstools/tools/misc.py
+++ b/src/gstools/tools/misc.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing miscellaneous tools.
 
diff --git a/src/gstools/tools/special.py b/src/gstools/tools/special.py
index b5cd6bd6..c48887ea 100644
--- a/src/gstools/tools/special.py
+++ b/src/gstools/tools/special.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing special functions.
 
diff --git a/src/gstools/transform/__init__.py b/src/gstools/transform/__init__.py
index cffe744f..9f9344c1 100644
--- a/src/gstools/transform/__init__.py
+++ b/src/gstools/transform/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing transformations to post-process normal fields.
 
diff --git a/src/gstools/transform/array.py b/src/gstools/transform/array.py
index e1b88ac6..32005f00 100644
--- a/src/gstools/transform/array.py
+++ b/src/gstools/transform/array.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing array transformations.
 
diff --git a/src/gstools/transform/field.py b/src/gstools/transform/field.py
index 795ed2a1..9ac33b6c 100644
--- a/src/gstools/transform/field.py
+++ b/src/gstools/transform/field.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing field transformations.
 
diff --git a/src/gstools/variogram/__init__.py b/src/gstools/variogram/__init__.py
index 62122ad0..59e10f55 100644
--- a/src/gstools/variogram/__init__.py
+++ b/src/gstools/variogram/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for estimating and fitting variograms.
 
diff --git a/src/gstools/variogram/binning.py b/src/gstools/variogram/binning.py
index b005d466..be490110 100644
--- a/src/gstools/variogram/binning.py
+++ b/src/gstools/variogram/binning.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing binning routines.
 
diff --git a/src/gstools/variogram/estimator.pyx b/src/gstools/variogram/estimator.pyx
index a3f40b5e..55e7b91a 100644
--- a/src/gstools/variogram/estimator.pyx
+++ b/src/gstools/variogram/estimator.pyx
@@ -1,6 +1,5 @@
 #cython: language_level=3, boundscheck=False, wraparound=False, cdivision=True
 # distutils: language = c++
-# -*- coding: utf-8 -*-
 """
 This is the variogram estimater, implemented in cython.
 """
@@ -251,7 +250,7 @@ def unstructured(
     else:
         distance = dist_haversine
         if dim != 2:
-            raise ValueError('Haversine: dim = {0} != 2'.format(dim))
+            raise ValueError('Haversine: dim = {} != 2'.format(dim))
 
     if pos.shape[1] != f.shape[1]:
         raise ValueError('len(pos) = {0} != len(f) = {1} '.
diff --git a/src/gstools/variogram/variogram.py b/src/gstools/variogram/variogram.py
index fc65d8c9..b57e0354 100644
--- a/src/gstools/variogram/variogram.py
+++ b/src/gstools/variogram/variogram.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 GStools subpackage providing tools for estimating and fitting variograms.
 
diff --git a/tests/test_condition.py b/tests/test_condition.py
index 2e70d9c2..e6b0c0cc 100644
--- a/tests/test_condition.py
+++ b/tests/test_condition.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """This is the unittest of CondSRF class."""
 import unittest
 from copy import copy
diff --git a/tests/test_covmodel.py b/tests/test_covmodel.py
index 3b9b5eaa..b4344cc2 100644
--- a/tests/test_covmodel.py
+++ b/tests/test_covmodel.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of CovModel class.
 """
diff --git a/tests/test_field.py b/tests/test_field.py
index c33a78c1..cdb0365d 100644
--- a/tests/test_field.py
+++ b/tests/test_field.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 """
 This is the unittest of SRF class.
 """
diff --git a/tests/test_incomprrandmeth.py b/tests/test_incomprrandmeth.py
index 0403f90c..9156b1b1 100644
--- a/tests/test_incomprrandmeth.py
+++ b/tests/test_incomprrandmeth.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of the RandMeth class.
 """
diff --git a/tests/test_krige.py b/tests/test_krige.py
index afcdf838..a37bf1e1 100644
--- a/tests/test_krige.py
+++ b/tests/test_krige.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of the kriging module.
 """
diff --git a/tests/test_latlon.py b/tests/test_latlon.py
index 6f035a3a..10d9f682 100644
--- a/tests/test_latlon.py
+++ b/tests/test_latlon.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest for latlon related routines.
 """
diff --git a/tests/test_normalizer.py b/tests/test_normalizer.py
index 03480da5..9ab0f45e 100644
--- a/tests/test_normalizer.py
+++ b/tests/test_normalizer.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of the Normalizer class.
 """
diff --git a/tests/test_randmeth.py b/tests/test_randmeth.py
index 0930b0b6..1ed6cc1f 100644
--- a/tests/test_randmeth.py
+++ b/tests/test_randmeth.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of the RandMeth class.
 """
diff --git a/tests/test_rng.py b/tests/test_rng.py
index 23119921..8fe16728 100644
--- a/tests/test_rng.py
+++ b/tests/test_rng.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is the unittest of the RNG class.
 """
diff --git a/tests/test_srf.py b/tests/test_srf.py
index a96e0e6f..eb9468ca 100644
--- a/tests/test_srf.py
+++ b/tests/test_srf.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
 """
 This is the unittest of SRF class.
 """
diff --git a/tests/test_transform.py b/tests/test_transform.py
index 630f9fcd..eb2980e2 100644
--- a/tests/test_transform.py
+++ b/tests/test_transform.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """This is the unittest of the transform submodule."""
 import unittest
 
diff --git a/tests/test_variogram_structured.py b/tests/test_variogram_structured.py
index e1ad1908..e0a3525a 100644
--- a/tests/test_variogram_structured.py
+++ b/tests/test_variogram_structured.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is a unittest of the variogram module.
 """
diff --git a/tests/test_variogram_unstructured.py b/tests/test_variogram_unstructured.py
index 2e873537..10b085bf 100644
--- a/tests/test_variogram_unstructured.py
+++ b/tests/test_variogram_unstructured.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 This is a unittest of the variogram module.
 """