System Dynamics

Diagram Model saved in JSON format:

{ "class": "go.GraphLinksModel",
          "linkLabelKeysProperty": "labelKeys",
          "nodeDataArray": [
        {"key":"grass", "category":"stock", "label":"Grass", "loc":"30 220", "label_offset":"0.5 0.5 0 30"},
        {"key":"cloud1", "category":"cloud", "loc":"200 220"},
        {"key":"sheep", "category":"stock", "label":"Sheep", "loc":"30 20","label_offset":"0.5 0.5 0 -30"},
        {"key":"cloud2", "category":"cloud", "loc":"200 20"},
        {"key":"cloud3", "category":"cloud", "loc":"-150 220"},
        {"key":"grass_loss", "category":"valve", "label":"grass_loss","label_offset":"0.5 0.5 0 20" },
        {"key":"grazing", "category":"valve", "label":"grazing","label_offset":"0.5 0.5 45 0" },
        {"key":"growth", "category":"valve", "label":"growth","label_offset":"0.5 0.5 0 20" },
        {"key":"sheep_loss", "category":"valve",  "label":"sheep_loss","label_offset":"0.5 0.5 0 20" },
        {"key":"k1", "category":"variable",  "label":"good weather", "loc": "-80 100"},
        {"key":"k2", "category":"variable",  "label":"bad weather", "loc": "100 150"},
        {"key":"k3", "category":"variable",  "label":"wolves", "loc": "150 -40"}
          ],
          "linkDataArray": [
        {"from":"grass", "to":"cloud1", "category":"flow", "labelKeys":[ "grass_loss" ]},
        {"from":"sheep", "to":"cloud2", "category":"flow", "labelKeys":[ "sheep_loss" ]},
        {"from":"grass", "to":"sheep", "category":"flow", "labelKeys":[ "grazing" ]},
        {"from":"cloud3", "to":"grass", "category":"flow", "labelKeys":[ "growth" ]},
        {"from":"grass", "to":"grass_loss", "category":"influence"},
        {"from":"sheep", "to":"sheep_loss", "category":"influence"},
        {"from":"grass", "to":"growth", "category":"influence"},
        {"from":"grass", "to":"grazing", "category":"influence"},
        {"from":"sheep", "to":"grazing", "category":"influence"},
        {"from":"k1", "to":"growth", "category":"influence"},
        {"from":"k1", "to":"grazing", "category":"influence"},
        {"from":"k2", "to":"grass_loss", "category":"influence"},
        {"from":"k3", "to":"sheep_loss", "category":"influence"}
          ]
        }