3.1 INTRODUCTION
For some scenarios it is interesting to define areas where land use changes are
restricted because of spatial policies, e.g. the conservation of nature. In Section 2.3 we
have seen that spatial policies should be defined in an ‘area restriction’ file. This file
contains a map of the study area indicating the extent of the case-study area and the
zones of the case-study area where spatial restrictions apply.
The ‘area restriction’ file is located in the installation directory and called ‘region*.fil’
where * can be defined by the user to indicate the conditions specified in the file. With
the DEMO version of CLUE-S three different area restriction files are supplied, one
without any spatial policy and two file indicating different extents of a nature reserve.
Import these ‘area restriction’ files in ArcView using File | Import Data Source | ASCII
Raster.
In this exercise we will create a new ‘area restriction’ file to simulate a scenario of the
effects of a strict protection of all remaining lowland forest on Sibuyan island. Therefore
we assume that during the simulations it is not possible to convert any of the remaining
forest areas below an altitude of 100 meter.
PREPARATION OF THE AREA RESTRICTION FILE
To make the area restriction file we need to identify:
The extent of the case study
The locations below 100 meter altitude
The locations with forest at the start of the simulations
Therefore it is needed to import the land use map of year 0 (the start of the simulations)
in ArcView. This land use map shows the extent of the study area (all grid-cells that are
designated to a land use type) and the locations with forest at the start of the
simulations. This land use map can be found (in ASCII format) in the installation
directory and is called .
To identify the locations below 100 meter an altitude map is needed. Since altitude is
one of the location factors used in the simulations for Sibuyan island this map is already
present in the installation directory. For this case study altitude is location factor number
7 in file ‘sc1gr7.fil’.
Import the ASCII files of land use at the start of the simulation and altitude in ArcView
or ArcMap.
Select all locations with forest located below an altitude of 100 meter at the start of the
simulation by a ‘map query’ (Analysis | Map Query) or ‘raster calculation’ (Figure 17).
This will result in a new theme indicating all selected locations.
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Figure 17. Map query with ArcView
In the ‘area restriction’ file the following coding should be used:
0: all grid cells that belong to the study area outside the ‘restricted
area’
-9998: all grid cells for which land use conversions are not allowed during
the simulations (the ‘restricted area’)
‘No Data’ or -9999: all other grid cells (outside the simulation area)
Prepare an ‘area restriction’ file. You can follow the steps below or use your own
procedure:
Classify the land use map of year 0 to identify all cells inside the case study area
(reclassify all land use types to 0; Analysis | Reclassify).
Overlay the result with the forest areas below 100 meter. This can be done by the Map
Calculator (Analysis | Map Calculator).
The result only needs to be reclassified to the coding system of the area restriction file,
as listed above (Analysis | Reclassify).
Save this theme as a grid (Theme | Save Data Set).
Export this theme as an ASCII file (File | Export Data Source) into the installation
directory with a name following ‘region*.fil’ (where * can be defined by the user).