diff --git a/app/models/champs/carte_champ.rb b/app/models/champs/carte_champ.rb
index 8e5c6bb3d..c7631b1ad 100644
--- a/app/models/champs/carte_champ.rb
+++ b/app/models/champs/carte_champ.rb
@@ -62,6 +62,14 @@ class Champs::CarteChamp < Champ
     end
   end
 
+  def selection_utilisateur_size
+    if geo_json.present?
+      geo_json['coordinates'].size
+    else
+      0
+    end
+  end
+
   def to_render_data
     {
       position: position,
diff --git a/app/views/shared/champs/carte/_geo_areas.html.haml b/app/views/shared/champs/carte/_geo_areas.html.haml
index 03d02e6e8..b2a990f8d 100644
--- a/app/views/shared/champs/carte/_geo_areas.html.haml
+++ b/app/views/shared/champs/carte/_geo_areas.html.haml
@@ -6,7 +6,7 @@
     - elsif champ.value.blank?
       Aucune zone tracée
     - elsif champ.quartiers_prioritaires.blank?
-      = t('errors.messages.quartiers_prioritaires_empty', count: champ.geo_json.size)
+      = t('errors.messages.quartiers_prioritaires_empty', count: champ.selection_utilisateur_size)
     - else
       %ul
         - champ.quartiers_prioritaires.each do |qp|
@@ -20,7 +20,7 @@
     - elsif champ.value.blank?
       Aucune zone tracée
     - elsif champ.cadastres.blank?
-      = t('errors.messages.cadastres_empty', count: champ.geo_json.size)
+      = t('errors.messages.cadastres_empty', count: champ.selection_utilisateur_size)
     - else
       %ul
         - champ.cadastres.each do |pc|
@@ -34,7 +34,7 @@
     - elsif champ.value.blank?
       Aucune zone tracée
     - elsif champ.parcelles_agricoles.blank?
-      = t('errors.messages.parcelles_agricoles_empty', count: champ.geo_json.size)
+      = t('errors.messages.parcelles_agricoles_empty', count: champ.selection_utilisateur_size)
     - else
       %ul
         - champ.parcelles_agricoles.each do |pa|
diff --git a/spec/models/champs/carte_champ_spec.rb b/spec/models/champs/carte_champ_spec.rb
index 7c8c6f0cf..8d0875a88 100644
--- a/spec/models/champs/carte_champ_spec.rb
+++ b/spec/models/champs/carte_champ_spec.rb
@@ -60,4 +60,38 @@ describe Champs::CarteChamp do
       it { is_expected.to eq(render_data) }
     end
   end
+
+  describe '#selection_utilisateur_size' do
+    subject { champ.selection_utilisateur_size }
+
+    context 'when the value is nil' do
+      let(:value) { nil }
+
+      it { is_expected.to eq(0) }
+    end
+
+    context 'when the value is blank' do
+      let(:value) { '' }
+
+      it { is_expected.to eq(0) }
+    end
+
+    context 'when the value is empty array' do
+      let(:value) { '[]' }
+
+      it { is_expected.to eq(0) }
+    end
+
+    context 'when the value is coordinates' do
+      let(:value) { coordinates.to_json }
+
+      it { is_expected.to eq(1) }
+    end
+
+    context 'when the value is geojson' do
+      let(:value) { geo_json }
+
+      it { is_expected.to eq(1) }
+    end
+  end
 end