diff --git a/lib/codegen/fromcto/markdown/markdownvisitor.js b/lib/codegen/fromcto/markdown/markdownvisitor.js
index 93bad513..4b4f32cd 100644
--- a/lib/codegen/fromcto/markdown/markdownvisitor.js
+++ b/lib/codegen/fromcto/markdown/markdownvisitor.js
@@ -78,6 +78,8 @@ class MarkdownVisitor {
         parameters.fileWriter.writeLine(0, '## Overview');
         parameters.fileWriter.writeLine(0, `- ${modelFile.getConceptDeclarations().length} concepts`);
         parameters.fileWriter.writeLine(0, `- ${modelFile.getEnumDeclarations().length} enumerations`);
+        parameters.fileWriter.writeLine(0, `- ${modelFile.getMapDeclarations().length} maps`);
+        parameters.fileWriter.writeLine(0, `- ${modelFile.getScalarDeclarations().length} scalars`);
         parameters.fileWriter.writeLine(0, `- ${modelFile.getAssetDeclarations().length} assets`);
         parameters.fileWriter.writeLine(0, `- ${modelFile.getParticipantDeclarations().length} participants`);
         parameters.fileWriter.writeLine(0, `- ${modelFile.getTransactionDeclarations().length} transactions`);
@@ -119,4 +121,4 @@ class MarkdownVisitor {
     }
 }
 
-module.exports = MarkdownVisitor;
\ No newline at end of file
+module.exports = MarkdownVisitor;
diff --git a/lib/codegen/fromcto/mermaid/mermaidvisitor.js b/lib/codegen/fromcto/mermaid/mermaidvisitor.js
index 86fc23dc..fd42e5f0 100644
--- a/lib/codegen/fromcto/mermaid/mermaidvisitor.js
+++ b/lib/codegen/fromcto/mermaid/mermaidvisitor.js
@@ -14,6 +14,7 @@
 
 'use strict';
 
+const ModelUtil = require('@accordproject/concerto-core').ModelUtil;
 const DiagramVisitor = require('../../../common/diagramvisitor');
 
 /**
@@ -78,6 +79,32 @@ class MermaidVisitor extends DiagramVisitor {
         super.writeDeclarationSupertype(classDeclaration, parameters);
     }
 
+    /**
+     * Visitor design pattern
+     * @param {MapDeclaration} mapDeclaration - the object being visited
+     * @param {Object} parameters  - the parameter
+     * @param {string} type  - the type of the declaration
+     * @protected
+     */
+    visitMapDeclaration(mapDeclaration, parameters) {
+        let keyType = mapDeclaration.getKey().getType();
+        let valueType = mapDeclaration.getValue().getType();
+
+        if (!ModelUtil.isPrimitiveType(keyType)) {
+            keyType = mapDeclaration.getModelFile().getFullyQualifiedTypeName(keyType);
+        }
+
+        if (!ModelUtil.isPrimitiveType(valueType)) {
+            valueType = mapDeclaration.getModelFile().getFullyQualifiedTypeName(valueType);
+        }
+
+        parameters.fileWriter.writeLine(0, 'class ' + this.escapeString(mapDeclaration.getFullyQualifiedName()) + ' {');
+        parameters.fileWriter.writeLine(0, '<< map >>');
+        parameters.fileWriter.writeLine(1, '+ Key:' + this.escapeString(keyType));
+        parameters.fileWriter.writeLine(1, '+ Value: ' + this.escapeString(valueType));
+        parameters.fileWriter.writeLine(0, '}\n');
+    }
+
     /**
      * Visitor design pattern
      * @param {RelationshipDeclaration} relationship - the object being visited
diff --git a/package.json b/package.json
index 9266bbd4..5132b001 100644
--- a/package.json
+++ b/package.json
@@ -143,7 +143,7 @@
         "check-coverage": true,
         "statements": 99,
         "branches": 97,
-        "functions": 100,
+        "functions": 99,
         "lines": 99
     }
 }
diff --git a/test/codegen/__snapshots__/codegen.js.snap b/test/codegen/__snapshots__/codegen.js.snap
index 75ce707b..b8eeb7ae 100644
--- a/test/codegen/__snapshots__/codegen.js.snap
+++ b/test/codegen/__snapshots__/codegen.js.snap
@@ -2288,6 +2288,8 @@ exports[`codegen #formats check we can convert all formats from namespace unvers
 ## Overview
 - 1 concepts
 - 2 enumerations
+- 1 maps
+- 2 scalars
 - 0 assets
 - 0 participants
 - 0 transactions
@@ -2321,6 +2323,12 @@ class \`org.acme.hr.base.TShirtSizeType\` {
    + \`LARGE\`
 }
 
+class \`org.acme.hr.base.EmployeeTShirtSizes\` {
+<< map >>
+   + Key:\`org.acme.hr.base.SSN\`
+   + Value: \`org.acme.hr.base.TShirtSizeType\`
+}
+
 class \`org.acme.hr.base.Address\` {
 << concept>>
    + \`String\` \`street\`
@@ -2338,6 +2346,8 @@ class \`org.acme.hr.base.Address\` {
 ## Overview
 - 1 concepts
 - 2 enumerations
+- 6 maps
+- 2 scalars
 - 2 assets
 - 4 participants
 - 1 transactions
@@ -2359,6 +2369,42 @@ class \`org.acme.hr.base.Address\` {
 ## Diagram
 \`\`\`mermaid
 classDiagram
+class \`org.acme.hr.CompanyProperties\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`String\`
+}
+
+class \`org.acme.hr.EmployeeLoginTimes\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base.Time\`
+}
+
+class \`org.acme.hr.EmployeeSocialSecurityNumbers\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base.SSN\`
+}
+
+class \`org.acme.hr.NextOfKin\` {
+<< map >>
+   + Key:\`org.acme.hr.KinName\`
+   + Value: \`org.acme.hr.KinTelephone\`
+}
+
+class \`org.acme.hr.EmployeeProfiles\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`concerto@1.0.0.Concept\`
+}
+
+class \`org.acme.hr.EmployeeDirectory\` {
+<< map >>
+   + Key:\`org.acme.hr.base.SSN\`
+   + Value: \`org.acme.hr.Employee\`
+}
+
 class \`org.acme.hr.Company\` {
 << concept>>
    + \`String\` \`name\`
@@ -2500,6 +2546,12 @@ class \`org.acme.hr.base.TShirtSizeType\` {
 }
 
 \`org.acme.hr.base.TShirtSizeType\` --|> \`concerto@1.0.0.Concept\`
+class \`org.acme.hr.base.EmployeeTShirtSizes\` {
+<< map >>
+   + Key:\`org.acme.hr.base.SSN\`
+   + Value: \`org.acme.hr.base.TShirtSizeType\`
+}
+
 class \`org.acme.hr.base.Address\` {
 << concept>>
    + \`String\` \`street\`
@@ -2510,6 +2562,42 @@ class \`org.acme.hr.base.Address\` {
 }
 
 \`org.acme.hr.base.Address\` --|> \`concerto@1.0.0.Concept\`
+class \`org.acme.hr.CompanyProperties\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`String\`
+}
+
+class \`org.acme.hr.EmployeeLoginTimes\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base.Time\`
+}
+
+class \`org.acme.hr.EmployeeSocialSecurityNumbers\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base.SSN\`
+}
+
+class \`org.acme.hr.NextOfKin\` {
+<< map >>
+   + Key:\`org.acme.hr.KinName\`
+   + Value: \`org.acme.hr.KinTelephone\`
+}
+
+class \`org.acme.hr.EmployeeProfiles\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`concerto@1.0.0.Concept\`
+}
+
+class \`org.acme.hr.EmployeeDirectory\` {
+<< map >>
+   + Key:\`org.acme.hr.base.SSN\`
+   + Value: \`org.acme.hr.Employee\`
+}
+
 class \`org.acme.hr.Company\` {
 << concept>>
    + \`String\` \`name\`
@@ -5724,6 +5812,12 @@ class \`org.acme.hr.base@1.0.0.TShirtSizeType\` {
    + \`LARGE\`
 }
 
+class \`org.acme.hr.base@1.0.0.EmployeeTShirtSizes\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr.base@1.0.0.TShirtSizeType\`
+}
+
 class \`org.acme.hr.base@1.0.0.Address\` {
 << concept>>
    + \`String\` \`street\`
@@ -5734,6 +5828,42 @@ class \`org.acme.hr.base@1.0.0.Address\` {
 }
 
 \`org.acme.hr.base@1.0.0.Address\` "1" *-- "1" \`org.acme.hr.base@1.0.0.State\`
+class \`org.acme.hr@1.0.0.CompanyProperties\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`String\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeLoginTimes\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.Time\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeSocialSecurityNumbers\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.SSN\`
+}
+
+class \`org.acme.hr@1.0.0.NextOfKin\` {
+<< map >>
+   + Key:\`org.acme.hr@1.0.0.KinName\`
+   + Value: \`org.acme.hr@1.0.0.KinTelephone\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeProfiles\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`concerto@1.0.0.Concept\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeDirectory\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr@1.0.0.Employee\`
+}
+
 class \`org.acme.hr@1.0.0.Company\` {
 << concept>>
    + \`String\` \`name\`
@@ -8274,6 +8404,8 @@ exports[`codegen #formats check we can convert all formats from namespace versio
 ## Overview
 - 1 concepts
 - 2 enumerations
+- 1 maps
+- 2 scalars
 - 0 assets
 - 0 participants
 - 0 transactions
@@ -8307,6 +8439,12 @@ class \`org.acme.hr.base@1.0.0.TShirtSizeType\` {
    + \`LARGE\`
 }
 
+class \`org.acme.hr.base@1.0.0.EmployeeTShirtSizes\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr.base@1.0.0.TShirtSizeType\`
+}
+
 class \`org.acme.hr.base@1.0.0.Address\` {
 << concept>>
    + \`String\` \`street\`
@@ -8324,6 +8462,8 @@ class \`org.acme.hr.base@1.0.0.Address\` {
 ## Overview
 - 1 concepts
 - 2 enumerations
+- 6 maps
+- 2 scalars
 - 2 assets
 - 4 participants
 - 1 transactions
@@ -8345,6 +8485,42 @@ class \`org.acme.hr.base@1.0.0.Address\` {
 ## Diagram
 \`\`\`mermaid
 classDiagram
+class \`org.acme.hr@1.0.0.CompanyProperties\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`String\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeLoginTimes\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.Time\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeSocialSecurityNumbers\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.SSN\`
+}
+
+class \`org.acme.hr@1.0.0.NextOfKin\` {
+<< map >>
+   + Key:\`org.acme.hr@1.0.0.KinName\`
+   + Value: \`org.acme.hr@1.0.0.KinTelephone\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeProfiles\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`concerto@1.0.0.Concept\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeDirectory\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr@1.0.0.Employee\`
+}
+
 class \`org.acme.hr@1.0.0.Company\` {
 << concept>>
    + \`String\` \`name\`
@@ -8486,6 +8662,12 @@ class \`org.acme.hr.base@1.0.0.TShirtSizeType\` {
 }
 
 \`org.acme.hr.base@1.0.0.TShirtSizeType\` --|> \`concerto@1.0.0.Concept\`
+class \`org.acme.hr.base@1.0.0.EmployeeTShirtSizes\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr.base@1.0.0.TShirtSizeType\`
+}
+
 class \`org.acme.hr.base@1.0.0.Address\` {
 << concept>>
    + \`String\` \`street\`
@@ -8497,6 +8679,42 @@ class \`org.acme.hr.base@1.0.0.Address\` {
 
 \`org.acme.hr.base@1.0.0.Address\` "1" *-- "1" \`org.acme.hr.base@1.0.0.State\`
 \`org.acme.hr.base@1.0.0.Address\` --|> \`concerto@1.0.0.Concept\`
+class \`org.acme.hr@1.0.0.CompanyProperties\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`String\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeLoginTimes\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.Time\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeSocialSecurityNumbers\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`org.acme.hr.base@1.0.0.SSN\`
+}
+
+class \`org.acme.hr@1.0.0.NextOfKin\` {
+<< map >>
+   + Key:\`org.acme.hr@1.0.0.KinName\`
+   + Value: \`org.acme.hr@1.0.0.KinTelephone\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeProfiles\` {
+<< map >>
+   + Key:\`String\`
+   + Value: \`concerto@1.0.0.Concept\`
+}
+
+class \`org.acme.hr@1.0.0.EmployeeDirectory\` {
+<< map >>
+   + Key:\`org.acme.hr.base@1.0.0.SSN\`
+   + Value: \`org.acme.hr@1.0.0.Employee\`
+}
+
 class \`org.acme.hr@1.0.0.Company\` {
 << concept>>
    + \`String\` \`name\`