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4. Block Definition File (block.dat) OPTIONALThis optional file can be used to group targets together or to use the facility thatallows the goal to be set as a proportion without calculating the actual amount inarea, length or number of occurrences. When using this file, the type of eachtarget must be set in the spec.dat file. If no grouping is necessary, the type namescan remain the same as the target id. If you are using a block definition file, it ishighly recommended that you read Game and Grantham (2008) to gain a betterunderstanding of how this file works. The contents of this file are:type targe t target2 targetocc sepnum sepdistance prop spfthe typeTheMini mum The number Target MinimumAn Thefor whichgoal clump ofnumber distance at alternativepenaltythe otherfor the size. If a occurrences of which to target. factorattributestarget clump of a of the target mutually planning This is the for thatare of the number of required. separated units proportiontarget.DEFAULTdefined given planningThis can be planning holding the of the(-1)CRITICALtype. units with used in units in target are totalDEFAULT(-1) the given conjunction valid considered amount oftarget is with or clumps. to be the targetDEFAULT (-1)below this instead ofseparated. whichDEFAULT (-1)size then it ‘target’.must beDEFAULT (-1)does notpreserved.count(N/A)toward thegoal.DEFAULT (-1)The values are separated by commas. The file structure looks like:type,target,target2,targetocc,sepnum,sepdistance,prop,spf1,-1,-1,-1,-1,-1,0.25,100002,-1,-1,-1,-1,-1,0.30,100005. Boundary Length File (bound.dat) OPTIONALThe boundary length file contains information on the boundary costs of adjacentplanning units. Although this is an optional file, it is highly recommended to usesince it helps set the level of fragmentation in the solution. Whereas this cost istypically the actual length of the boundary it can be modified to a ‘cost’ or‘effective length’ value to takeinto account boundaries that are particularlydesirable or undesirable. Bound.dat can be created automatically using theMarxan Input Generator. This table can have tabs or commas between thecolumns. If you see repeating PU ids in the bound file - these are "edge" planningunits and repeating them in the bound.dat file helps to avoid bias in the BLMbecause they have shorter 'shared' boundaries. It is not necessary to specifyboundary lengths for all planning units (where they are not specified, Marxan willassume there is no boundary between planning units). However any missingvalues within the file will prevent Marxan from running, for instance if ‘id1’ andTNC Protected Area Tools (PAT) Version 3.0The Nature Conservancy, August 200954