Hi Kat, It sounds to me that you could solve this by using an iterator to loop over field values. In that case you would be executing your model several times, with only changing source and destinations. Suppose you have a field with unique values (1 - 34) of your sources/destinations, then you can use the 'Iterate Field Values' for 33 times (skip the last). Each iteration will give you the value of a single source. By using this value in the definition query (UniqueValue = iterationValue) of the tool 'Make Feature Layer (Data Management)' you can create a source layer (not a physical file) that only contains this single location. Use the Make Feature Layer tool again with a different definition query (UniqueValue > iterationValue) to create the destination layer. Execute the cost distance with these layers. Some reading on iterators: A quick tour of using iterators Examples of using iterators in ModelBuilder Kind regards, Xander Hi Xander, Could you please expand on what you mean by the "definition query" of the Make Feature Layer tool? Also, should this tool be input into the model or should the temporary field be created beforehand? Thank you, Ashley Manning
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