Problem:  Find probable locations of Civil War Mobile Army Surgical Units during the Battle of Gettysburg.

Prodcedure Log:

Data shapefiles from the NPS and the PHPS

	SOILSPOL.shp, SOILSPOL.shx, SOILSPOL.dbf
	STREAMS.shp, STREAMS.shx, STREAMS.dbf
	ROADSARC.shp, ROADSARC.shx, ROADSARC.dbf
	HISTLAND.arc, HISTLAND.shx, HISTLAND,dbf
	battles1.shp, battles1.shx, battles2.dbf
	battles2.shp, battles2.shx, battles2.dbf
	artifacts.shp, artifacts.shx, artifacts.dbf
	coordinate data stored in:  meters

Add shapefiles to ArcMap; set map units to meters

Merge battles1 and battles2 layers together:  Tools > GeoProcessing Wizard

	Layers to merge together:  battles1-Polygon, battles2-Polygon
	Use fields from:  battles1-Polygon
	Output shapefile:  battlesmerge.shp

Create 2000 foot battlesmerge buffer: Tools > Buffer Wizard:

	Layer to buffer: battlesmerge.shp
	Buffer distance: 2000 feet
	Dissolve barriers: yes
	Create buffers so they are:  Outside polygons and include inside
	Output shapefile: battlebuffer.shp (1 record)

Use Select by Attributes to select the residential areas in the HISTLAND layer:

	Layer to select from:  HISTLAND.shp
	Method:  Create a new selection
	Query:  "LAND_USE"='residnt'
	Result:  127 records selected from HISTLAND.shp

Create new (selection) layer of residential areas - name: residential.shp (127 records)

Create 2000 foot residential buffer: Tools > Buffer Wizard:

	Layer to buffer: residential.shp
	Buffer distance: 2000 feet
	Dissolve barriers: yes
	Create buffers so they are:  Outside polygons and include inside
	Output shapefile: resbuffer.shp (1 record)

Clip the battlebuffer layer by using the resbuffer layer:  Tools > GeoProcessing Wizard

	Input layer to clip:  battlebuffer.shp
	Polygon clip layer:  resbuffer.shp
	Output shapefile:  battleres.shp (2 records)

Dissolve SOILSPOL layer: Tools > GeoProcessing Wizard:

	Input layer: SOILSPOL
	Attribute on which to dissolve: SLOPE
	Output shapefile: slopedissolve.shp
	Additional fields: (accept default)

Use Select by Attributes to select where SLOPE is classified as 'A' in the slopedissolve layer:

	Layer to select from:  slopedissolve.shp
	Method:  Create a new selection
	Query:  "SLOPE"='A'
	Result:  1 records selected from slopedissolve.shp

Create new (selection) layer of slopedissolve - name: slopeA.shp (1 record)

Clip the battleres layer by using the slopeA layer:  Tools > GeoProcessing Wizard

	Input layer to clip:  battleres.shp
	Polygon clip layer:  slopeA.shp
	Output shapefile:  bareslopeA.shp (89 records)

Create 200 foot artifacts buffer: Tools > Buffer Wizard:

	Layer to buffer: artifacts.shp
	Buffer distance: 200 feet
	Dissolve barriers: yes
	Output shapefile: artifactsbuffer.shp (49 records)

Clip the bareslopeA layer by using the artifactsbuffer layer:  Tools > GeoProcessing Wizard

	Input layer to clip:  bareslopeA.shp
	Polygon clip layer:  artifactsbuffer.shp
	Output shapefile:  bareslopeArt.shp (33 records)

Create 500 foot ROADSARC buffer: Tools > Buffer Wizard:

	Layer to buffer: ROADSARC.shp
	Buffer distance: 500 feet
	Dissolve barriers: yes
	Output shapefile: roadbuffer.shp (2 records)

Clip the roadbuffer layer by using the bareslopeArt layer:  Tools > GeoProcessing Wizard

	Input layer to clip:  roadbuffer.shp
	Polygon clip layer:  bareslopeArt.shp
	Output shapefile:  robareslopeArt.shp (20 records)

Create 200 foot STREAMS buffer: Tools > Buffer Wizard:

	Layer to buffer: STREAMS.shp
	Buffer distance: 200 feet
	Dissolve barriers: yes
	Output shapefile: streambuffer.shp (12 records)

Clip the streambuffer layer by using the robareslopeArt layer:  Tools > GeoProcessing Wizard

	Input layer to clip:  streambuffer.shp
	Polygon clip layer:  robareslopeArt.shp
	Output shapefile:  strobareslopeArt.shp (8 records)

Determine area of each suitable area polygon (strobareslopeArt.shp):

	Open strobareslopeArt attribute table and add field:
		Name: area_sqmet
		Type: Double
		Precision: 12
		Scale: 2

	Calculate values for area_sqmet field: Pre-Logic VBA Script Code:
		Dim dblArea as double
		Dim pArea as IArea
		Set pArea = [shape]
		dblArea = pArea.area
		In text box: area_sqmet = dblArea

Find the polygon in the strobareslopeArt layer that has the largest contiguous area (primary dig site):

	Open strobareslopeArt attribute table and right-click the area_sqmet field;
	Select Sort Descending and the top record will have the largest contiguous area in the area_sqmet field.
	Result:  The primary dig site to locate a Civil War Mobile Army Surgical Unit has an area of 7591.71 sq. meters.