Adv_GIS

1
Tables and Attributes

• Week3, Fall 2003

2
Object model for tables

• the table document you use in ArcView is a user
  interface for a VTab (a virtual table). You can
  only do a few things with the table document
  itself (sort and promote), the majority of your
  work will be with VTab
• The VTab is built from one or more physical
  tabular sources on disk (INFO,dBASE or txt). The
  sources are presented to you as a single virtual
  table. You can edit,query and extend your
  tables.
• Each VTab has two Bitmaps, a selection Bitmap and
  a definition Bitmap

3
Add theme from xy coords

• Create a text file (xy_table.txt) with No. X, Y
  as headings and (1,-85.71,36.17),(2,-85.39,36.21)
  , (3, -85.29, 36.02), (4, -85.63,36.04). Use
  Notepad and save the file with txt extension
  (xy_table.txt) to your folder.
• Create a New Project and Add New View (you may
  use the script from your previous homework) and
  name the View as Putnam
• Add putshape.shp from the folder
  U\4850_5850\Data_Center\week4 using script (from
  your previous homework) See demo.
• theFileName "c\4850\data_center\week3\xy_table.
  txt".AsFileName
• theVTab VTab.Make(theFilename, false, false)
• myTable Table.Make(theVTab)
• myTable.SetName(XY_Table)
• myTable.GetWin.Open 'Open the new table document

skipFirst line
forWrite
4
VTab.Make(aFileName,ForWrite,SkipFirst)

• Makes the VTab from aFileName. aFileName may be
  either an INFO file, a dBASE file, or a text
  file.
• If forWrite is TRUE, the VTab will start out
  editable. If aFileName is a text file, forWrite
  must be FALSE.
• If skipFirst is TRUE, the VTab will not include
  the first record of the disk file this feature
  is useful for polygon attribute tables because it
  drops the universe polygon.
• Use VTab.MakeNew if you want to create a new file.

5
Create Point theme

• theViewav.FindDoc(Putnam County") finding
  Putnam County for theView, you can use
  GetActiveDoc
• theVTabav.GetProject.FindDoc(XY_Table").GetVTab
• xFieldtheVTab.FindField(X")
• yFieldtheVTab.FindField(Y")
• xySourceXYName.Make(theVTab,xField,yField)
• theThemeTheme.Make(xySource)
• ptTheme theView.AddTheme(theTheme)
• theTheme.SetVisible(true)

6
Creating, Opening and Closing a File

• The Make request to the TextFile or LineFile
  classes creates new files or opens existing
  files. Lets create a text file
• Create a text file to write to and read from
• if the file exists, overwrite it.
• myTextFile TextFile.Make(myTextFilename,,
  FILE_PERM_WRITE)
• Open a line file for reading.
• myLineFile LineFile.make(myLineFilename,
  FILE_PERM_READ)

7
Create a new Table file

• If you need a completely new table to store data
  you dont already have on disk, youll need to
  create a file on disk, a new VTab object, and
  then the Table object.
• Create a new Table file
• myFile FileDialog.Put(xyz.dbf.AsFilename,.,
  File)
• theVTab VTab.MakeNew(myFile,dbase)
• myTable Table.Make(theVTab)
• myTable.SetName(xyz)
• VTab.MakeNew (aFileName, aClass) - Make a new
  table and give a filename and file type dbase,
  info, or dtext

8
FileDialog.Put(defaultFileName,aPattern,
FileWinTitle)

• Creates a file window for making new files. The
  FileName defaultFileName serves as the default
  value. The path of the defaultFileName is the
  beginning directory for the Put. aPattern defines
  the pattern for similar files. Use an asterisk as
  a wild card character (".ave"). FileWinTitle is
  the file window title. If no title is specified,
  it defaults to Save. If the user names or selects
  a file then clicks OK, Put returns a FileName for
  that file. If the user names an existing file,
  Put queries to replace the existing file. If the
  user clicks Cancel, Put returns nil.

FileDialog.Show(.shp, Shape Files , )
9
Create fields/Add Values

• We have a table w/o fields. To create fields in
  the dBASE file, we must create fields in the
  VTab. Field is a class associated with VTab. The
  following script creates two new field objects,
  then adds them to the VTab, and thus to the file
  on disk.
• 'Create two fields.. one integer, one character
• myTable av.FindDoc("xyz")
• theVTab myTable.GetVTab
• f1 Field.Make("ID",FIELD_SHORT,5,0)
• f2Field.Make("Name",FIELD_CHAR,13,0)
• 'Add Fields
• theVTab.AddFields(f1,f2)
• 'Add 100 records and set initial values to match
  ID value
• for each i in 1 .. 100
• rec theVTab.AddRecord
• theVTab.SetValue(f1,rec,i)
• theVTab.SetValue(f2,rec,"Cookeville"
  i.AsString)
• end

10
Field.Make

• Field.Make (aName, aFieldType, aWidth,
  aPrecision)
• For numeric fields, aWidth includes a count for
  the decimal point the field containing 123.4567
  is 8 wide with precision 4. For non-numeric
  fields, aPrecision must be 0.

• aVTab.SetValue (aField, aRecordNumber, anObj)
• Sets the current value of aField (if editable) of
  record aRecordNumber to anObj.

11
Sorting and Promoting

• myTable.PromoeSelection move selected records to
  top
• myTable.Sort(aField, ascending) sort table on
  field

12
Exercise

• Creating a table with file name Radius_Area.dbf
  
• Add three fields in the table named
• f1 Field.Make("ID",FIELD_SHORT,5,0)
  f2Field.Make(Radius,FIELD_DECIMAL, 5,2),
  f3Field.Make(AreaFIELD_DECIMAL,14,2)
• have 10 records in each field and calculate the
  areas of the circle with radius from 1 to 10)
  radius ID 2, Area 3.14RadiusRadius
• Bring it into the current project, and
• SetName(Radius_Area)

13
Exercise create table with ID, Two random
numbers and populated with 5 points

• Use the following script
• theMaxX -85.26
• theMinX -85.68
• theMaxY 36.22
• theMinY 36.08
• nBig 100
• XRandom Number.MakeRandom(0, nBig)/nBig
  (theMaxX - theMinX) theMinX
• YRandom Number.MakeRandom(0, nBig)/nBig
  (theMaxY - theMinY) theMinY
• MsgBox.Info("The XRandom is " XRandom.AsString,
  "X Random")
• MsgBox.Info("The YRandom is " YRandom.AsString,
  "Y Random")
• 'msgBox.ListAsString(theMinX.AsString,
  TheMaxX.AsString, theMinY.AsString,
  theMaxY.AsString, XRandom.AsString,
  YRandom.AsString, "", "")
• theRandomPoint Point.Make(XRandom, YRandom)

14
Flashing shapes

• theView av.FindDoc("Putnam County")
• theDisplay theView.GetDisplay
• theXYTheme theView.FindTheme("XY")
• theFTab theXYTheme.GetFTab
• theShapeField theFTab.FindField("Shape")
• Milliseconds 500
• Times 1
• for each i in 0..4
• theShape theFTab.returnValue(theShapeField,
  i)
• '
• aGraphic GraphicShape.Make(theShape)
• theSymbol aGraphic.GetSymbol
• theDisplay.FlashShape(theShape, theSymbol,
  Milliseconds, Times)
• end

15
Run script from another script

• ChineseZodiac MsgBox.Input(What is your
  Chinese Zodiac symbol?,Symbol,)
• av.Run(AnotherScriptName,valuesToPass)

16
Homework 3

• Due on midnight of 9/18/03