implement null-elevation-fix transformer

6 files changed, 160 insertions, 105 deletions

diff --git a/fietsboek/locale/de/LC_MESSAGES/messages.mo b/fietsboek/locale/de/LC_MESSAGES/messages.mo
index 7092994..6043d8e 100644
--- a/fietsboek/locale/de/LC_MESSAGES/messages.mo
+++ b/fietsboek/locale/de/LC_MESSAGES/messages.mo
diff --git a/fietsboek/locale/de/LC_MESSAGES/messages.po b/fietsboek/locale/de/LC_MESSAGES/messages.po
index dfa2bed..8787ec2 100644
--- a/fietsboek/locale/de/LC_MESSAGES/messages.po
+++ b/fietsboek/locale/de/LC_MESSAGES/messages.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2022-12-10 17:37+0100\n"
+"POT-Creation-Date: 2023-02-15 23:01+0100\n"
 "PO-Revision-Date: 2022-07-02 17:35+0200\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: de\n"
@@ -18,39 +18,39 @@ msgstr ""
 "Content-Transfer-Encoding: 8bit\n"
 "Generated-By: Babel 2.11.0\n"
 
-#: fietsboek/util.py:274
+#: fietsboek/util.py:273
 msgid "password_constraint.mismatch"
 msgstr "Passwörter stimmen nicht überein"
 
-#: fietsboek/util.py:276
+#: fietsboek/util.py:275
 msgid "password_constraint.length"
 msgstr "Passwort zu kurz"
 
-#: fietsboek/models/track.py:543
+#: fietsboek/models/track.py:565
 msgid "tooltip.table.length"
 msgstr "Länge"
 
-#: fietsboek/models/track.py:544
+#: fietsboek/models/track.py:566
 msgid "tooltip.table.uphill"
 msgstr "Bergauf"
 
-#: fietsboek/models/track.py:545
+#: fietsboek/models/track.py:567
 msgid "tooltip.table.downhill"
 msgstr "Bergab"
 
-#: fietsboek/models/track.py:546
+#: fietsboek/models/track.py:568
 msgid "tooltip.table.moving_time"
 msgstr "Fahrzeit"
 
-#: fietsboek/models/track.py:547
+#: fietsboek/models/track.py:569
 msgid "tooltip.table.stopped_time"
 msgstr "Haltezeit"
 
-#: fietsboek/models/track.py:549
+#: fietsboek/models/track.py:571
 msgid "tooltip.table.max_speed"
 msgstr "Maximalgeschwindigkeit"
 
-#: fietsboek/models/track.py:553
+#: fietsboek/models/track.py:575
 msgid "tooltip.table.avg_speed"
 msgstr "Durchschnittsgeschwindigkeit"
 
@@ -438,6 +438,10 @@ msgstr "Bildbeschreibung"
 msgid "page.track.form.image_description_modal.save"
 msgstr "Übernehmen"
 
+#: fietsboek/templates/edit_form.jinja2:166
+msgid "page.track.form.transformer.enable"
+msgstr "Transformation anwenden"
+
 #: fietsboek/templates/finish_upload.jinja2:8
 #: fietsboek/templates/upload.jinja2:6
 msgid "page.upload.title"
@@ -460,47 +464,47 @@ msgstr "Startseite"
 msgid "page.home.total"
 msgstr "Gesamt"
 
-#: fietsboek/templates/layout.jinja2:35
+#: fietsboek/templates/layout.jinja2:36
 msgid "page.navbar.toggle"
 msgstr "Navigation umschalten"
 
-#: fietsboek/templates/layout.jinja2:46
+#: fietsboek/templates/layout.jinja2:47
 msgid "page.navbar.home"
 msgstr "Startseite"
 
-#: fietsboek/templates/layout.jinja2:49
+#: fietsboek/templates/layout.jinja2:50
 msgid "page.navbar.browse"
 msgstr "Stöbern"
 
-#: fietsboek/templates/layout.jinja2:53
+#: fietsboek/templates/layout.jinja2:54
 msgid "page.navbar.upload"
 msgstr "Hochladen"
 
-#: fietsboek/templates/layout.jinja2:62
+#: fietsboek/templates/layout.jinja2:63
 msgid "page.navbar.user"
 msgstr "Nutzer"
 
-#: fietsboek/templates/layout.jinja2:66
+#: fietsboek/templates/layout.jinja2:67
 msgid "page.navbar.welcome_user"
 msgstr "Willkommen, {}!"
 
-#: fietsboek/templates/layout.jinja2:69
+#: fietsboek/templates/layout.jinja2:70
 msgid "page.navbar.logout"
 msgstr "Abmelden"
 
-#: fietsboek/templates/layout.jinja2:72
+#: fietsboek/templates/layout.jinja2:73
 msgid "page.navbar.profile"
 msgstr "Profil"
 
-#: fietsboek/templates/layout.jinja2:76
+#: fietsboek/templates/layout.jinja2:77
 msgid "page.navbar.admin"
 msgstr "Admin"
 
-#: fietsboek/templates/layout.jinja2:82
+#: fietsboek/templates/layout.jinja2:83
 msgid "page.navbar.login"
 msgstr "Anmelden"
 
-#: fietsboek/templates/layout.jinja2:86
+#: fietsboek/templates/layout.jinja2:87
 msgid "page.navbar.create_account"
 msgstr "Konto Erstellen"
 
@@ -626,6 +630,14 @@ msgstr "Anfrage senden"
 msgid "page.upload.form.gpx"
 msgstr "GPX Datei"
 
+#: fietsboek/transformers/__init__.py:130
+msgid "transformers.fix-null-elevation.title"
+msgstr "Nullhöhen beheben"
+
+#: fietsboek/transformers/__init__.py:134
+msgid "transformers.fix-null-elevation.description"
+msgstr "Diese Transformation passt die Höhenangabe für Punkte an, bei denen die Höhenangabe fehlt."
+
 #: fietsboek/views/account.py:54
 msgid "flash.invalid_name"
 msgstr "Ungültiger Name"
@@ -649,15 +661,15 @@ msgstr ""
 msgid "flash.a_confirmation_link_has_been_sent"
 msgstr "Ein Bestätigungslink wurde versandt"
 
-#: fietsboek/views/admin.py:49
+#: fietsboek/views/admin.py:48
 msgid "flash.badge_added"
 msgstr "Wappen hinzugefügt"
 
-#: fietsboek/views/admin.py:73
+#: fietsboek/views/admin.py:72
 msgid "flash.badge_modified"
 msgstr "Wappen bearbeitet"
 
-#: fietsboek/views/admin.py:93
+#: fietsboek/views/admin.py:92
 msgid "flash.badge_deleted"
 msgstr "Wappen gelöscht"
 
@@ -705,43 +717,43 @@ msgstr "E-Mail-Adresse bestätigt"
 msgid "flash.password_updated"
 msgstr "Passwort aktualisiert"
 
-#: fietsboek/views/detail.py:101
+#: fietsboek/views/detail.py:140
 msgid "flash.track_deleted"
 msgstr "Strecke gelöscht"
 
-#: fietsboek/views/profile.py:61
+#: fietsboek/views/profile.py:60
 msgid "flash.personal_data_updated"
 msgstr "Persönliche Daten wurden gespeichert"
 
-#: fietsboek/views/profile.py:79
+#: fietsboek/views/profile.py:78
 msgid "flash.friend_not_found"
 msgstr "Das angegebene Konto wurde nicht gefunden"
 
-#: fietsboek/views/profile.py:85
+#: fietsboek/views/profile.py:84
 msgid "flash.friend_already_exists"
 msgstr "Dieser Freund existiert bereits"
 
-#: fietsboek/views/profile.py:93
+#: fietsboek/views/profile.py:92
 msgid "flash.friend_added"
 msgstr "Freund hinzugefügt"
 
-#: fietsboek/views/profile.py:103
+#: fietsboek/views/profile.py:102
 msgid "flash.friend_request_sent"
 msgstr "Freundschaftsanfrage gesendet"
 
-#: fietsboek/views/upload.py:56
+#: fietsboek/views/upload.py:52
 msgid "flash.no_file_selected"
 msgstr "Keine Datei ausgewählt"
 
-#: fietsboek/views/upload.py:66
+#: fietsboek/views/upload.py:62
 msgid "flash.invalid_file"
 msgstr "Ungültige GPX-Datei gesendet"
 
-#: fietsboek/views/upload.py:189
+#: fietsboek/views/upload.py:182
 msgid "flash.upload_success"
 msgstr "Hochladen erfolgreich"
 
-#: fietsboek/views/upload.py:205
+#: fietsboek/views/upload.py:198
 msgid "flash.upload_cancelled"
 msgstr "Hochladen abgebrochen"
 
diff --git a/fietsboek/locale/en/LC_MESSAGES/messages.mo b/fietsboek/locale/en/LC_MESSAGES/messages.mo
index 7827a62..4f35491 100644
--- a/fietsboek/locale/en/LC_MESSAGES/messages.mo
+++ b/fietsboek/locale/en/LC_MESSAGES/messages.mo
diff --git a/fietsboek/locale/en/LC_MESSAGES/messages.po b/fietsboek/locale/en/LC_MESSAGES/messages.po
index f4b0239..5f3ab68 100644
--- a/fietsboek/locale/en/LC_MESSAGES/messages.po
+++ b/fietsboek/locale/en/LC_MESSAGES/messages.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2022-12-10 17:37+0100\n"
+"POT-Creation-Date: 2023-02-15 23:01+0100\n"
 "PO-Revision-Date: 2022-06-28 13:11+0200\n"
 "Last-Translator: \n"
 "Language: en\n"
@@ -18,39 +18,39 @@ msgstr ""
 "Content-Transfer-Encoding: 8bit\n"
 "Generated-By: Babel 2.11.0\n"
 
-#: fietsboek/util.py:274
+#: fietsboek/util.py:273
 msgid "password_constraint.mismatch"
 msgstr "Passwords don't match"
 
-#: fietsboek/util.py:276
+#: fietsboek/util.py:275
 msgid "password_constraint.length"
 msgstr "Password not long enough"
 
-#: fietsboek/models/track.py:543
+#: fietsboek/models/track.py:565
 msgid "tooltip.table.length"
 msgstr "Length"
 
-#: fietsboek/models/track.py:544
+#: fietsboek/models/track.py:566
 msgid "tooltip.table.uphill"
 msgstr "Uphill"
 
-#: fietsboek/models/track.py:545
+#: fietsboek/models/track.py:567
 msgid "tooltip.table.downhill"
 msgstr "Downhill"
 
-#: fietsboek/models/track.py:546
+#: fietsboek/models/track.py:568
 msgid "tooltip.table.moving_time"
 msgstr "Moving Time"
 
-#: fietsboek/models/track.py:547
+#: fietsboek/models/track.py:569
 msgid "tooltip.table.stopped_time"
 msgstr "Stopped Time"
 
-#: fietsboek/models/track.py:549
+#: fietsboek/models/track.py:571
 msgid "tooltip.table.max_speed"
 msgstr "Max Speed"
 
-#: fietsboek/models/track.py:553
+#: fietsboek/models/track.py:575
 msgid "tooltip.table.avg_speed"
 msgstr "Average Speed"
 
@@ -434,6 +434,10 @@ msgstr "Image description"
 msgid "page.track.form.image_description_modal.save"
 msgstr "Apply"
 
+#: fietsboek/templates/edit_form.jinja2:166
+msgid "page.track.form.transformer.enable"
+msgstr "Apply transformation"
+
 #: fietsboek/templates/finish_upload.jinja2:8
 #: fietsboek/templates/upload.jinja2:6
 msgid "page.upload.title"
@@ -456,47 +460,47 @@ msgstr "Home"
 msgid "page.home.total"
 msgstr "Total"
 
-#: fietsboek/templates/layout.jinja2:35
+#: fietsboek/templates/layout.jinja2:36
 msgid "page.navbar.toggle"
 msgstr "Toggle navigation"
 
-#: fietsboek/templates/layout.jinja2:46
+#: fietsboek/templates/layout.jinja2:47
 msgid "page.navbar.home"
 msgstr "Home"
 
-#: fietsboek/templates/layout.jinja2:49
+#: fietsboek/templates/layout.jinja2:50
 msgid "page.navbar.browse"
 msgstr "Browse"
 
-#: fietsboek/templates/layout.jinja2:53
+#: fietsboek/templates/layout.jinja2:54
 msgid "page.navbar.upload"
 msgstr "Upload"
 
-#: fietsboek/templates/layout.jinja2:62
+#: fietsboek/templates/layout.jinja2:63
 msgid "page.navbar.user"
 msgstr "User"
 
-#: fietsboek/templates/layout.jinja2:66
+#: fietsboek/templates/layout.jinja2:67
 msgid "page.navbar.welcome_user"
 msgstr "Welcome, {}!"
 
-#: fietsboek/templates/layout.jinja2:69
+#: fietsboek/templates/layout.jinja2:70
 msgid "page.navbar.logout"
 msgstr "Logout"
 
-#: fietsboek/templates/layout.jinja2:72
+#: fietsboek/templates/layout.jinja2:73
 msgid "page.navbar.profile"
 msgstr "Profile"
 
-#: fietsboek/templates/layout.jinja2:76
+#: fietsboek/templates/layout.jinja2:77
 msgid "page.navbar.admin"
 msgstr "Admin"
 
-#: fietsboek/templates/layout.jinja2:82
+#: fietsboek/templates/layout.jinja2:83
 msgid "page.navbar.login"
 msgstr "Login"
 
-#: fietsboek/templates/layout.jinja2:86
+#: fietsboek/templates/layout.jinja2:87
 msgid "page.navbar.create_account"
 msgstr "Create Account"
 
@@ -622,6 +626,14 @@ msgstr "Send request"
 msgid "page.upload.form.gpx"
 msgstr "GPX file"
 
+#: fietsboek/transformers/__init__.py:130
+msgid "transformers.fix-null-elevation.title"
+msgstr "Fix null elevation"
+
+#: fietsboek/transformers/__init__.py:134
+msgid "transformers.fix-null-elevation.description"
+msgstr "This transformer fixes the elevation of points whose elevation is unset."
+
 #: fietsboek/views/account.py:54
 msgid "flash.invalid_name"
 msgstr "Invalid name"
@@ -645,15 +657,15 @@ msgstr ""
 msgid "flash.a_confirmation_link_has_been_sent"
 msgstr "A confirmation link has been sent"
 
-#: fietsboek/views/admin.py:49
+#: fietsboek/views/admin.py:48
 msgid "flash.badge_added"
 msgstr "Badge has been added"
 
-#: fietsboek/views/admin.py:73
+#: fietsboek/views/admin.py:72
 msgid "flash.badge_modified"
 msgstr "Badge has been modified"
 
-#: fietsboek/views/admin.py:93
+#: fietsboek/views/admin.py:92
 msgid "flash.badge_deleted"
 msgstr "Badge has been deleted"
 
@@ -700,43 +712,43 @@ msgstr "Your email address has been verified"
 msgid "flash.password_updated"
 msgstr "Password has been updated"
 
-#: fietsboek/views/detail.py:101
+#: fietsboek/views/detail.py:140
 msgid "flash.track_deleted"
 msgstr "Track has been deleted"
 
-#: fietsboek/views/profile.py:61
+#: fietsboek/views/profile.py:60
 msgid "flash.personal_data_updated"
 msgstr "Personal data has been updated"
 
-#: fietsboek/views/profile.py:79
+#: fietsboek/views/profile.py:78
 msgid "flash.friend_not_found"
 msgstr "The friend was not found"
 
-#: fietsboek/views/profile.py:85
+#: fietsboek/views/profile.py:84
 msgid "flash.friend_already_exists"
 msgstr "Friend already exists"
 
-#: fietsboek/views/profile.py:93
+#: fietsboek/views/profile.py:92
 msgid "flash.friend_added"
 msgstr "Friend has been added"
 
-#: fietsboek/views/profile.py:103
+#: fietsboek/views/profile.py:102
 msgid "flash.friend_request_sent"
 msgstr "Friend request sent"
 
-#: fietsboek/views/upload.py:56
+#: fietsboek/views/upload.py:52
 msgid "flash.no_file_selected"
 msgstr "No file selected"
 
-#: fietsboek/views/upload.py:66
+#: fietsboek/views/upload.py:62
 msgid "flash.invalid_file"
 msgstr "Invalid GPX file selected"
 
-#: fietsboek/views/upload.py:189
+#: fietsboek/views/upload.py:182
 msgid "flash.upload_success"
 msgstr "Upload successful"
 
-#: fietsboek/views/upload.py:205
+#: fietsboek/views/upload.py:198
 msgid "flash.upload_cancelled"
 msgstr "Upload cancelled"
 
diff --git a/fietsboek/locale/fietslog.pot b/fietsboek/locale/fietslog.pot
index a86c43b..05bc70a 100644
--- a/fietsboek/locale/fietslog.pot
+++ b/fietsboek/locale/fietslog.pot
@@ -1,14 +1,14 @@
 # Translations template for PROJECT.
-# Copyright (C) 2022 ORGANIZATION
+# Copyright (C) 2023 ORGANIZATION
 # This file is distributed under the same license as the PROJECT project.
-# FIRST AUTHOR <EMAIL@ADDRESS>, 2022.
+# FIRST AUTHOR <EMAIL@ADDRESS>, 2023.
 #
 #, fuzzy
 msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2022-12-10 17:37+0100\n"
+"POT-Creation-Date: 2023-02-15 23:01+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -17,39 +17,39 @@ msgstr ""
 "Content-Transfer-Encoding: 8bit\n"
 "Generated-By: Babel 2.11.0\n"
 
-#: fietsboek/util.py:274
+#: fietsboek/util.py:273
 msgid "password_constraint.mismatch"
 msgstr ""
 
-#: fietsboek/util.py:276
+#: fietsboek/util.py:275
 msgid "password_constraint.length"
 msgstr ""
 
-#: fietsboek/models/track.py:543
+#: fietsboek/models/track.py:565
 msgid "tooltip.table.length"
 msgstr ""
 
-#: fietsboek/models/track.py:544
+#: fietsboek/models/track.py:566
 msgid "tooltip.table.uphill"
 msgstr ""
 
-#: fietsboek/models/track.py:545
+#: fietsboek/models/track.py:567
 msgid "tooltip.table.downhill"
 msgstr ""
 
-#: fietsboek/models/track.py:546
+#: fietsboek/models/track.py:568
 msgid "tooltip.table.moving_time"
 msgstr ""
 
-#: fietsboek/models/track.py:547
+#: fietsboek/models/track.py:569
 msgid "tooltip.table.stopped_time"
 msgstr ""
 
-#: fietsboek/models/track.py:549
+#: fietsboek/models/track.py:571
 msgid "tooltip.table.max_speed"
 msgstr ""
 
-#: fietsboek/models/track.py:553
+#: fietsboek/models/track.py:575
 msgid "tooltip.table.avg_speed"
 msgstr ""
 
@@ -431,6 +431,10 @@ msgstr ""
 msgid "page.track.form.image_description_modal.save"
 msgstr ""
 
+#: fietsboek/templates/edit_form.jinja2:166
+msgid "page.track.form.transformer.enable"
+msgstr ""
+
 #: fietsboek/templates/finish_upload.jinja2:8
 #: fietsboek/templates/upload.jinja2:6
 msgid "page.upload.title"
@@ -453,47 +457,47 @@ msgstr ""
 msgid "page.home.total"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:35
+#: fietsboek/templates/layout.jinja2:36
 msgid "page.navbar.toggle"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:46
+#: fietsboek/templates/layout.jinja2:47
 msgid "page.navbar.home"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:49
+#: fietsboek/templates/layout.jinja2:50
 msgid "page.navbar.browse"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:53
+#: fietsboek/templates/layout.jinja2:54
 msgid "page.navbar.upload"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:62
+#: fietsboek/templates/layout.jinja2:63
 msgid "page.navbar.user"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:66
+#: fietsboek/templates/layout.jinja2:67
 msgid "page.navbar.welcome_user"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:69
+#: fietsboek/templates/layout.jinja2:70
 msgid "page.navbar.logout"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:72
+#: fietsboek/templates/layout.jinja2:73
 msgid "page.navbar.profile"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:76
+#: fietsboek/templates/layout.jinja2:77
 msgid "page.navbar.admin"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:82
+#: fietsboek/templates/layout.jinja2:83
 msgid "page.navbar.login"
 msgstr ""
 
-#: fietsboek/templates/layout.jinja2:86
+#: fietsboek/templates/layout.jinja2:87
 msgid "page.navbar.create_account"
 msgstr ""
 
@@ -617,6 +621,14 @@ msgstr ""
 msgid "page.upload.form.gpx"
 msgstr ""
 
+#: fietsboek/transformers/__init__.py:130
+msgid "transformers.fix-null-elevation.title"
+msgstr ""
+
+#: fietsboek/transformers/__init__.py:134
+msgid "transformers.fix-null-elevation.description"
+msgstr ""
+
 #: fietsboek/views/account.py:54
 msgid "flash.invalid_name"
 msgstr ""
@@ -637,15 +649,15 @@ msgstr ""
 msgid "flash.a_confirmation_link_has_been_sent"
 msgstr ""
 
-#: fietsboek/views/admin.py:49
+#: fietsboek/views/admin.py:48
 msgid "flash.badge_added"
 msgstr ""
 
-#: fietsboek/views/admin.py:73
+#: fietsboek/views/admin.py:72
 msgid "flash.badge_modified"
 msgstr ""
 
-#: fietsboek/views/admin.py:93
+#: fietsboek/views/admin.py:92
 msgid "flash.badge_deleted"
 msgstr ""
 
@@ -689,43 +701,43 @@ msgstr ""
 msgid "flash.password_updated"
 msgstr ""
 
-#: fietsboek/views/detail.py:101
+#: fietsboek/views/detail.py:140
 msgid "flash.track_deleted"
 msgstr ""
 
-#: fietsboek/views/profile.py:61
+#: fietsboek/views/profile.py:60
 msgid "flash.personal_data_updated"
 msgstr ""
 
-#: fietsboek/views/profile.py:79
+#: fietsboek/views/profile.py:78
 msgid "flash.friend_not_found"
 msgstr ""
 
-#: fietsboek/views/profile.py:85
+#: fietsboek/views/profile.py:84
 msgid "flash.friend_already_exists"
 msgstr ""
 
-#: fietsboek/views/profile.py:93
+#: fietsboek/views/profile.py:92
 msgid "flash.friend_added"
 msgstr ""
 
-#: fietsboek/views/profile.py:103
+#: fietsboek/views/profile.py:102
 msgid "flash.friend_request_sent"
 msgstr ""
 
-#: fietsboek/views/upload.py:56
+#: fietsboek/views/upload.py:52
 msgid "flash.no_file_selected"
 msgstr ""
 
-#: fietsboek/views/upload.py:66
+#: fietsboek/views/upload.py:62
 msgid "flash.invalid_file"
 msgstr ""
 
-#: fietsboek/views/upload.py:189
+#: fietsboek/views/upload.py:182
 msgid "flash.upload_success"
 msgstr ""
 
-#: fietsboek/views/upload.py:205
+#: fietsboek/views/upload.py:198
 msgid "flash.upload_cancelled"
 msgstr ""
 
diff --git a/fietsboek/transformers/__init__.py b/fietsboek/transformers/__init__.py
index b22c492..1f084a0 100644
--- a/fietsboek/transformers/__init__.py
+++ b/fietsboek/transformers/__init__.py
@@ -11,6 +11,7 @@ function to load and apply transformers.
 
 from abc import ABC, abstractmethod
 from collections.abc import Mapping
+from itertools import chain, islice
 from typing import TypeVar
 
 from gpxpy.gpx import GPX
@@ -145,7 +146,25 @@ class FixNullElevation(Transformer):
         pass
 
     def execute(self, gpx):
-        print("YALLA YALLA")
+        def all_points():
+            return (
+                point
+                for track in gpx.tracks
+                for segment in track.segments
+                for point in segment.points
+            )
+
+        points = all_points()
+        previous_points = chain([None], all_points())
+        next_points = chain(islice(all_points(), 1, None), [None])
+
+        for previous_point, point, next_point in zip(previous_points, points, next_points):
+            if point.elevation == 0.0:
+                if previous_point:
+                    point.elevation += previous_point.elevation
+                if next_point:
+                    point.elevation += next_point.elevation
+                point.elevation /= sum(1 for pt in [previous_point, next_point] if pt)
 
 
 def list_transformers() -> list[type[Transformer]]: