Output textfiles

 

Results of the centrality analyses are output as tab-delimited text files (.tab) of the format:

 

hex_id value

 

Output shapefiles

 

Shapefiles are produced by the Toolkit when the .asc file is initially converted to the hexmap format used by the Toolkit. These shapefiles allow the text file of results to be represented spatially.

 

In order to display the results spatially, the text file (or files if several different analyses were run) will need to be joined to the 'hex_id' field of the shapefile created during the analysis process (see below). In ArcGIS, you can access data in delimited text files and work with them as tables using either ArcCatalog or the Add Data dialog box in ArcMap. Files with a .tab extension should be automatically interpreted as tab delimited by ArcGIS.

 

You can join the table to a shapefile using either the Add Join function (under Data Management) or the Join Data dialog box, accessed by right-clicking a layer in ArcMap.

 

Alternately, using ArcGIS Workstation, you can create an INFO file from the textfile and use JOINITEM to join it to a coverage created from the shapefile.

 

We are considering development of a ArcGIS Toolbox to facilitate postprocessing of Toolkit output. If you have suggestions for this, please post comments to the Google Groups forum.

 

Hexmaps files represent a format used internally by the Toolkit (and Hexsim, a program for spatial population viability analysis [see Related Resources])

 

Graph format files

 

Various types of graph format files are produced in the course of analysis. Each one is appropriate to a different set of connectivity analysis methods. Thus it is possible to get meaningless results by producing the wrong input graph format for the analysis desired.

 

The types of graph format files available are:

 

LEMON graph format files (LGF)

Nodes are listed first. Then edges (arcs) are listed.

There are five fields per line in the edge section of the lgf: source_node, target_node, edge_label, edge_capacity, edge_cost.

 

1) LGF Directed - Used for time-series analysis using min-cost-max-flow

 

2) LGF Undirected - Used for min-cost-max-flow analyses (non-time-series, i.e., of a single map)

 

Example of lgf file

 

@nodes

1

2

...

@arcs

     label capacity cost

1 2 0 1000 1000

1 63 1 1000 1000

2 3 2 1000 1000

2 64 3 1065 1000

2 63 4 1000 1000

2 1 5 1000 1000

3 4 6 1000 1000

 

Edgelist textfiles

Each line represents an edge.

There are three fields per line: from_node, to_node, attribute

 

3) Edge list with Distance attribute - Used for shortest-path betweenness analyses

 

4) Edge list with Conductance attribute - Used for current flow betweenness analyses

 

5) Edge list - Directed - Used for PageRank analyses  (experimental)

 

 

Example of edgelist file

 

1 2 642.6068

1 157 644.6428

2 3 726.2068

2 158 704.6395

2 157 695.9301

2 1 642.6068

3 4 669.7904

3 159 679.8489

3 158 736.9523

3 2 726.2068

4 5 615.8793

4 160 612.6219

...