Using Meff Tool

After going over the instructions on how to use the effective mesh size tool in ArcGIS, I attempted to try it for myself. Here's a screenshot of the tool with the selected layers.



To my understanding, the ny_footprint layer should be put in the barrier layer field since it's the one with all the linear features. A new field (patch) was created in the attribute table. The instructions mentions that the areas that are not covered by fragmenting elements (the suitable patches) should be coded as 1 in some fields (barrier layer field). Hence, since these are all fragmenting elements, all fields were coded as 0. I'm a little confused if this layer is the appropriate one to use in this instance given that there are no features representing habitat patches, which would be represented by 1's. However, upon running the tool I noticed that the following fields all had values of 0: "AreaIntSct", "AreaMult", "AreaIntSq". As a result, I ran the tool once more with all values in the new field "patch" as 1's and a whole set of values appeared in the three fields listed above.

The nypr_lmu_mar08 layer with the different LMUs and sub-units was used as the map unit layer given that it represents the planning unit areas that will be used to calculate the effective mesh size. A new field was also created in the attributes table since a unique numerical value was needed for each different value (SUB_NAME) for the map unit field. The new field is called SUM_LMU. The output directory c:\Patrick\ was used and the resulting folder (Run Name) was called intersect. The tool ran successfully and the resulting layer "intersect" was added automatically. Buffers around all features are now shaded for this layer.

The next step is to figure out what exactly the fields in the intersect layer's attribute table mean. Upon viewing the attribute table, I noticed there were numerous blank fields. I may be wrong, but these might represent polygons resulting from the added buffers. I need to confirm if I ran the tool with the correct layers.

Also, I will need to figure out how to isolate certain features in order to create different fragmentation geometries (i.e. seismic lines).

To do:

• Do further reading on effective mesh size in order to understand how to interpret it;
• Start written report as mentionned yesterday.