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+#Data model
+## Organisms (crops, pests, diseases and weeds)
+Crops, pests, diseases and weeds are all organisms subject to [classification](https://en.wikipedia.org/wiki/Taxonomy_(biology)#Modern_system_of_classification). In VIPS, they are all placed in the organisms table. Following the rules of the classification system, the table is a tree structure. So each node (bar the root/top nodes) have a parent organism - which may be a family, genus etc.
+
+### Crop categories
+Each organization (NIBIO, Jordbruksverket, ADAS etc.) has their own set of crop categories. They can be e.g. cereals, fruit, vegetables. Each of these links to one or more organisms.
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