USGS - science for a changing world

Alaska Science Center

white dothome: white dotscience: white dothighlights: white dotmaps, products & publications: white dotpartners & education: white dotcontact us:   white dotinternal:

DOUGLAS ARGOS-FILTER ALGORITHM

ANIMAL MOVEMENT


SPATIAL TOOLS

SPATIAL TOOLS ARCVIEW EXTENSION

Introduction
Data Format
Views
Bibliography

Loading this Extension:  Spatial Tools is an ArcView  program extension which must be run simultaneously with Spatial Analyst.  After downloading, unzip the .avx file directly (or unzip to a temp directory, then copy) to the ArcView EXT32 folder.  Start the ArcView program, click on "file" and go to "extensions".  From the list of available extensions, select Spatial Analyst, then Spatial Tools and click "ok".  The collection of new functions  will now be available through  menu choices, tools, and buttons described below. When installing version 3.2 (10/99), Spatial Analyst will automatically load after selecting the Spatial Tools 3.2 extension.

Note...you must install the g2i.dll file in to the $AVBIN directory (which is now included in the latest version, v. 3.2).

Using this documentation:  Click on the menu bar above to go to the major headings and then click on either the subheading list or the image map of menu choices or buttons.  Click on the return button to get back to the subheading list.

For any questions or problems regarding this documentation, contact elizabeth_solomon@nps.gov.
 

Introduction

Spatial tools is an ArcView extension which provides a collection of grid tools made available through the program's  GUI (Graphical User Interface).  Menus, Tools, and buttons provide access to various spatial modeling and analysis capabilities such as geometric transformations, mosaicking, resolution alteration, data clean-up and spatial analysis.   Spatial Analyst  must be loaded simultaneously.

Requirements: ArcView and Spatial Analyst. This program will work in versions of ArcView on PC, UNIX and Macintosh hardware.  On the PC platform it is recommended that a Pentium or Pentium Pro 200 or faster be used with this program and at least 32 megabytes of memory, since Spatial Analyst must be running simultaneously.

Other grid operations and functions not currently available through Spatial Analyst or Spatial Tools menus can be accessed through the use of the additional extensions and Avenue Requests.  Help for these requests and extensions can be found in the ArcView On-Line Help Documentation and/or at  http://www.esri.com/.
 

Hydrologic Modeling Extension (v1.1)
Flow Accumulation
Flow Direction 
Flow Length 
Delineate Watershed
Area/Perimeter/Length of watersheds
Focal Flow
Snap Pour Point 
Stream Order
Identify/Fill Sinks 
Flow Length by Watershed
Shape Factor by Watershed
Centroid as Point Shape 
Pour Points as Point Shape
Mean Watershed Elevation/Slope/CurveNumber/Precipitation

Visibility Extension
Line of Sight
 

Other Avenue Requests
Flip
Mirror
Shrink
Expand
CostDistance
CostPath
ReturnCostPath
Curvature
Lookup
BlockStats
Focal Stats
Slice
ZonalFill

 

 
 
Data Format

The majority of functions in Spatial Tools operate primarily on grid theme data (ARC GRID format).  The exceptions are the Profile and Profile with Feature Points operations which require a combination of active grid, line and point feature themes, and  Clip Grid, which requires a selected graphic object as well as an active grid theme to perform the analysis.  The menu choices Set to View and Set from View  each require a separate existing view in the project and the Type in to Link and Type in from Link work  with an existing table (which can be created using the Create Link Table option).

Menu choices are performed on selected (active) feature themes, after which the user is prompted to enter or select from a list of variables.  Tool buttons are utilized by clicking the tool and then clicking in the view to perform the function.
 


 
 
Views

VIEW MENU CHOICES

Select a Menu Item


 
 
 
 
 
 
 
 
 
 
 

Addition to Version 3.2 menu (10/99):

Changes to Version 3.0 menus include the following: Select a Button

Select a Tool



TRANSFORMATION MENU

Merge Grids

Runs the MergeGrid request based on user input; Merges two or more adjacent grids into one grid.
Cells in common or overlapping areas are assigned values based on the sequence of grids entered (highest priority goes to the grids entered first).

Mosaic

Runs Mosaic request based on user input.  Creates one grid from two or more adjacent grids, Overlapping or common areas between grids are "smoothed" using a calculated weighted average.  The maximum number of grids that can be combined is 50.

In the following example, 3 grids were mosaiced to create a new grid with smooth boundaries.

Combine Grids

Combines the first selected grid with grids selected from the file dialog to create a grid of unique values.

Clip Grid

Extracts a new grid by clipping to the inside or outside of an overlaying graphic object.

Select graphic object

Choose "clip inside" or "clip outside'

The following set of tools are used in the georeferencing/warp operation for grid data sets:
Note...Online help for the warp procedure is available from ArcView's Help Menu

Set From View
Specifies the view to be used as the From View in the Warp operation.

Set To View
Specifies the View to be used as the To View in the warp operation.

Set Link Table
Specifies the Table to be used as the Link Table (a table containing "from" and "to" link coordinates) in the warp operation.

Create Link Table
Creates (and sets) an empty Link Table to be used in the warp operation.

Type in From Link
Allows the user the option to manually type in a "from" link coordinate in to the Link Table instead of clicking in the "From View".

Type in To Link
Allows the user the option to manually type in a "to" link coordinate into the Link Table instead of clicking in the "To View".

Warp
Starts the warp calculation on an active grid theme.  After creating/setting the "From" and "To" views, creating/setting the link table, and building a list of coordinates in the table, the user must select the "From View", and is prompted to enter the polynomial order to be used, as well as the desired resampling method (Nearest Neigbor, Bilinear, or Cubic Convolution).The new dataset will be added to the "to" view and named "Warp of (original grid theme)".
 
 

Aggregate

Aggregates a grid using the selected method.  Using a user-prompted statistical method (maximum, mean, medium, minimum or sum), this function alters the resolution of a grid by performing aggregation calculations on groups of cells with the same value.  The result is a new grid resampled to a coarser resolution.

The following bathymetry grid was aggregated using maximum values for depth and a cell factor of 3.  The resulting grid been resampled to a coarser resolution.


 

Grid to Image

Takes a grid or set of grids that were created from a true color image and converts them into a BSQ, BIL, BIP, JPG or TIFF image.
All of the grids must be from the same source image and must be of the integer type.  Cell values cannot exceed 255.

The g2i.dll file must be placed into the bin32 directory to work properly.

CLEAN UP MENU

Majority Filter

Runs MajorityFilter request on active grid theme.
Smoothes data by replacing cell values in the active grid with the majority (most frequent) value of neighboring cells.  Select diagonal neighbors (true/false)  and halfok (majority or half) options to decide which and how many of the  neighboring cells will be used to determine majority values.

In the following example, the majority filter function has smoothed out the data by replacing misclassified cells (dark green areas of vegetation occurring in water) with new values using the most frequently occurring values of neighboring cells.
 
 

Region Group

Runs RegionGroup request on active theme.
Creates a region for every contiguous group of cells with the same value.

Extract by Count

Runs grid ExtractByAttribute request on active grid theme; Prompts to enter TheCount (Cells < TheCount are set to NoData in the new theme, otherwise cells retain their original values).

In the following landcover grid, the original values which represent  "shadows"  (displayed in black) were set to to No Data by entering a count of 1500.  The new grid represents the original values for all  data with a count greater than 1500.

Nibble

Prompts for mask grid, analysis grid, and request variables; runs the Nibble request, ignores active themes.
Uses a mask grid to replace NoData cell values of the active grid (input grid) with the values of the nearest neighboring cell.

Boundary Clean

Runs BoundaryClean request on active grid theme.
Cleans (smoothes) transition areas between grid zones using expand and shrink methods.

Thin

Runs Thin request on active grid theme.
Shrinks linear features in the active grid to one pixel width.  Prompts for the following variables:

notBinary (TRUE = all values other than No Data are thinned.  FALSE =  only values greater than 0 are thinned).
doFilter (TRUE =  the Grid is filtered to smooth the boundaries between values. FALSE = no filter is used).
sharpenCorners (TRUE = rectangular corners and junctions are preserved. FALSE = all corners and junctions are smoothed).
maxThickness (can be a Number or Nil, that defines the maximum thickness, in map units, of linear features in the Grid. If maxThickness is set to Nil a value 10 times the cell size of aGrid is used).



ANALYSIS MENU

Resample

Changes the resolution of the active grid by interpolating values using a chosen resampling method (nearest-neighbor, bilinear, or cubic).

  • NEAREST NEIGHBOR:  Fastest of the 3 interpolation methods. It is mainly used for categorical data, as it will not change cell values. The maximum spatial error will be one half the cell size.
  • BILINEAR:  Determines the new value of a cell based upon a weighted distance average of the four nearest input cell centers. It can be used for continuous data, and will cause some smoothing of the data.
  • CUBIC CONVOLUTION:  Determines the new value of a cell based upon a weighted distance average of the sixteen nearest input cell centers. It is used for continuous data and is geometrically less distorting than the Grid achieved by running the nearest neighbor method.  This method require the most processing time.
In the following example, the grid was resampled to a larger cell size using the nearest-neighbor method.


 

Random Grid
This function creates a random grid.  The user selects either a uniform random or a normal random grid, and is prompted as to whether or not the values are to be adjusted.

The following histograms illustrate the default values used in creating  uniformly and normally distributed random grids:
 

Uniform: Values are between 0 and 1 Normal:  Mean = 0 and Standard Deviation = 1

 

Pycnophylactic Interpolation
The program performs pycnophylactic interpolation on a categorical grid.
The analysis variable in the VTAB of the grid should represent a phenomenon that changes continuously over space.

Zonal Geometry Table

Creates a table containing various geometric calculations for each zone in the active grid.

Profile
 Used to create chart profiles of line features (streams, roads, trails, etc.) using a line theme and an an elevation grid theme.  Requires two active themes, the first a line theme (with records selected) and the second an elevation grid theme.  Merges selected lines, then finds interval points along the merged line at equal intervals.  User is queried for how many divisions of merged line.  Outputs a dbf file of distances starting at the lowest interval point and including all interval points and corresponding z values.  Outputs a line graph (profile) of distance from origin vs. z values if no more than about 100 interval points are produced.

In this example, the selected stream (shown highlighted in yellow) was profiled, using 5 equal divisions.  The chart below shows distance and corresponding elevation values.
 
 


 

Profile With Feature Points

Used to create elevation profiles of selected lines and selected point features.  Requires three active themes, the first a point theme (the feature points), the second a line theme and the third an elevation grid theme.User is queried for how many divisions of merged line.  Outputs a dbf file of distances starting at the lowest inerval point and including all interval points, feature points and corresponding z values.  Dbf table contains a "Type" field indicating whether a distance is an interval point or a feature point.  Outputs a scatter diagram graph (the line profile) of distance from origin vs. z values if no more than baout 50 points are produced.
 
 

Line or Point File Visibility

Conducts a visibility analysis of a line or point file.  This function requires the following fields in the input FTab, which are used to control the visibility analysis. These Fields are SPOT, OFFSETA, OFFSETB, AZIMUTH1, AZIMUTH2, VERT1, VERT2, RADIUS1 and RADIUS2.

If not specified, the default values in the Visibility Tool are are set as follows:
 
 

SPOT INTERPOLATED FROM THE INPUT GRID
OFFSETA 1
OFFSETB 0
AZIMUTH1 0
AZIMUTH2 360
VERT 90
VERT2 -90
RADIUS1 0
RADIUS2 INFINITY

 

 
 


  

VIEW TOOLS



Creates Warp start points (creates a "from link" in the "from" view).  Click on a location in the ungeoreferenced dataset to start building a list of "from links" (Points will automatically be labelled).  Use the delete links button to remove incorrect links from the table.

Creates Warp desired points (creates a "to link" in the "to" view).  Click on the desired location in the georeferenced dataset to start building a list of "to links" (Points will automatically be labelled).  Use the delete links button to remove incorrect links from the table.
 

Shifts the active grid to a new location  by clicking in the view to move its point of origin.Click the tool, then click on the desired location to shift to in the view.
 
 
 


VIEW BUTTONS
Deletes one or many links from the current link table.  Click the button, then select one or many links to delete from the table.

Rotates the active grid in a clockwise motion around the lower left-hand corner.

Click the button, then enter the number of degrees desired (and the resampling method to be used if multiples of 90 degrees are not used).  (See previous section on Resampling methods, for a description of the 3 types of interpolation).

In this example, a new grid was created, rotated 90 degrees around the original grid's lower laft-hand corner.
 
 


 


 
Bibliography

 

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://alaska.usgs.gov/science/biology/spatial/gistools/spatialtools_doc.php
Page Contact Information: ascweb@usgs.gov
Page Last Modified: June 23 2011 12:42:56.