intro. to gis pre-lab spatial analysis april 1 st , 2013
DESCRIPTION
Intro. To GIS Pre-Lab Spatial Analysis April 1 st , 2013. Spatial Analysis. The application of operations to coordinate and related attribute data Maps are great, but this is the real power of GIS Spatial analysis is used to explore or solve a problem using a variety of geoprocessing tools. - PowerPoint PPT PresentationTRANSCRIPT
Intro. To GISPre-Lab
Spatial AnalysisApril 1st , 2013
Spatial Analysis
• The application of operations to coordinate and related attribute data
• Maps are great, but this is the real power of GIS
• Spatial analysis is used to explore or solve a problem using a variety of geoprocessing tools
Calculate Geometry• Length, Area, or
X,Y coordinates• Choose coordinate
system of source or data frame
• Pick units of measurement
• Make sure field has units in the name
Types of Analysis
Layer 1
Function 1 Layer 2
Function 2 Layer 3
Function
Layer 2
Layer 1Layer
3
Dissolve Tool– Similar to the merge function in Editor
toolbar
Dissolve Tool
• Input Features• Output Feature Class• Dissolve field(s)
(optional)• Statistics (optional)
• Create multipart features (optional)
Buffering• Buffering creates a polygon using a
specified distance from a point, line, or other polygon
Buffer Tool
• Input Features• Output Feature
Class• Distance– Linear unit (pick
units)– Field (attribute table)
• Side/End type• Dissolve Type
Buffer application• 500 ft.
buffer applied to houses
• Buffer overlaps transfer station
Multiple-Ring Buffer• Creates buffers for many distances at
once• Dissolve option makes them non-
overlapping
Near Tool
• Calculates distance from input features to nearest feature in other layer(s)
Near Tool• Output has field with ID
and distance of feature
• Multiple near layers can be calculated at once
• Options to include:– Location (X,Y)– Angle (degrees)
Intersect
• Polygons split at feature boundaries of both datasets
• Only overlapping areas are kept
• Attribute tables are combined in output
Identity• Similar to
intersect but input features are not clipped
• Features split along identity polygon edges
• Attribute tables are combined in output
Union• Like Intersect
but both input and union features are retained
• Output features have attributes from both input and union layers
Intersect / Identity / UnionWhich function is which?