2002 ESRI Conference Highlights

George Lienkaemper

ArcGIS Spatial Analyst

Effects Toolbar

  • Adjust Contrast, Brightness, and Transparency

    Options>Analysis Environment

  • Working Directory - for temporary files
  • Mask - mask areas out of analysis
  • Spatial Reference - must be established
  • Analysis Extent - choose a portion of the display for analysis
  • Cell Size - defaults to larger cell size

    Data Exploration

  • Histogram can be developed from selection or from a graphic

    Temporary Data Sets

  • Everything created in an analysis session is stored as a temporary data set
  • Choose Make Permanent from the Context Menu

    Map Projections

  • On-the-fly projections are approximations used to speed up display
  • Don't export to Data Frame projection, use projection wizard or ArcInfo WS

    Analysis Tools

    Raster Calculator
  • Mathematical Operators and Functions used with layers in the dialog
  • Grid Map Algebra can also me used in dialog
  • Most grid functions and operators can be typed in (not commands)
    Distance and Proximity Analysis
  • Straight Line Distance
  • Allocation for proximity
  • Cost weighted path
  • Shortest path
    Density Mapping (not the same as surface interpolation)
  • Result is points per unit area

    Neighborhood Analysis

  • Cell functions - moving window for filtering, smoothing, data aggregation
  • Neighborhood - block statistics (in a variety of shapes)
  • Zonal Overlay - statistics by zones described as shapes, polys, or grids

    Interpolation and Contouring Tools

  • Minimum spline
  • IDW (inverse distance weighting)
  • Kriging

    Reclassification - Dialog used in both symbology and reclassification (Save & Load Reclass tables)

    Hydro and Ground Water Extension available through ArcObjects OnLine

    Statistical Modeling Tools available soon through ArcObjects OnLine

    Managing Raster Data in ArcSDE

    Excellent write-up of the information covered in these technical workshops in July issue of ArcUser.
    Online at arc user article

    Raster Characteristics

  • Spatial Resolution - cell size, numbers of rows and columns
  • Pixel Values
  • Data Depth - number of bits determines amount of data that can be stored
  • Data Type
  • Statistics
  • No Data Values (supported)
  • Bands - number of bands

    Raster Tables

  • Attribute table - description of values
  • Colormap table - lookup for data display
  • Spectral Resolution - which part of electromagnetic spectrum
  • Temporal Resolution - when data were collected
  • Spatial Reference - coordinate system / projection
  • Internal - .aux files (Grid, .img, GeoTiff, MrSid)
  • External - associated world file, no projection (jpeg, bmp)
  • Resampling - pyramid layers used in display
  • Discrete - scanned or classified data (nearest neighbor resampling)
  • Continuous - photos, dems, images (bilinear or cubic convolution)
  • Raster Compression - save disk space, faster i/o
  • Lossless (moderate compression ratios - 3:1)
  • Use for analysis or where original data must stay intact
  • Run-length encoding - LZ77
  • Lossy (high compression rations - 10, 20 or even 50:1)
  • Use for background data/images
  • JPEG or MrSid

    Raster Dataset Management

  • Mgmt in ArcCatalog
  • Export
  • MrSid
  • Geodatabase
  • Other Formats
  • Import using ArcToolbox
  • MrSid - ArcGis will read any size MrSid file
  • Writing rasters to MrSid has 50MB limit
  • Images can be mosaicked with Export
  • Rendering - unique, classified, stretched, RGB
  • Display manipulation - Check out Effects ToolBar
  • Projection-on-the-fly - use ArcToolbox or WS to reproject rasters
  • Georeferencing - GeoReferencing ToolBar
  • Calibrate - transformation is created and stored, no resampling
  • Rectification

    Rasters in Geodatabase

  • Raster stored inside RDBMS - enhances data sharing and speed
  • Centralized management, common format, data protection
  • Features pyramid layers, internal tiling, spatial indexing, and data compression
  • Supports large data sets as:
  • Seamless mosaics
  • All rasters stored as single row in table
  • Data without overlap, infrequent updating
  • Faster processing
  • Raster catalogs

    Each raster stored as separate row in table, can be accessed separately

  • Overlapping data where data must be maintained
  • Data that change frequently

    3D Analyst - ArcScene

  • Drape DOQ and extruded layer over tin to animate scene to create fly-through
  • Tips and Tricks
  • Don't save thumbnails by default
  • Learn control key functions
  • Avoid on-the-fly projection
  • Turn off layer visibility by default
  • Use bilinear interpolation in raster rendering

    Topology in ArcGIS

    See arcnews article
    Implemented in 8.3 release
    Set of integrity rules that define the behavior of spatially related features
    Spatial constraints you want to apply to your data
    Topology wizard to select which feature classes will participate and define the properties
    Coverage model automatically enforces up to 15 topology rules (depending on feature type)
    ArcGIS model provides 26 topology rules with more rule type to come
    Topology Properties
    Cluster tolerance (similar to fuzzy tolerance)
    Distance range in which verticies are considered coincident
    Coordinate accuracy ranks
    Establishes hierarchy for feature classes and controls how much a feature might move when topology is validated
    Validation
    Snaps features based on cluster tolerance
    Checks for rule violations - Error Inspector displays errors and exceptions
    Exceptions are rule violations that are determined to be OK