diff --git a/documentation/ER_diagram.gaphor b/documentation/ER_diagram.gaphor
new file mode 100644
index 0000000..8367b3f
--- /dev/null
+++ b/documentation/ER_diagram.gaphor
@@ -0,0 +1,182 @@
+
+
+
+
+
+New model
+
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+
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+
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+
+
+New diagram
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+
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+cls
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+
+New Diagram
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+HeightMap
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+
+
+(1.0, 0.0, 0.0, 1.0, 213.8203125, 137.04296875)
+
+
+(0.0, 0.0)
+
+
+100.0
+
+
+100.0
+
+
+
+
+
+0
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+
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+
+
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+
+
+
+x
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+
+int
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+
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+
+
+
+y
+
+
+int
+
+
+
+
+
+
+
+heights
+
+
+
+
+Countor
+
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+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+(1.0, 0.0, 0.0, 1.0, 374.1523132324219, 137.04296875)
+
+
+(0.0, 0.0)
+
+
+100.0
+
+
+108.0
+
+
+
+
+
+0
+
+
+
+
+
+
+
+
+
+
+x
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+y
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+cases
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\ No newline at end of file
diff --git a/documentation/ER_diagram.svg b/documentation/ER_diagram.svg
new file mode 100644
index 0000000..5d5779a
--- /dev/null
+++ b/documentation/ER_diagram.svg
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+
+