Geographic Information Systems Using ESRI ArcGIS 9.3 Advanced Editing: Attribute Table.

GeographicInformation

SystemsUsing

ESRI ArcGIS 9.3Advanced Editing:

Attribute Table

ATTRIBUTE TABLEMultiple field editing

Field calculator

Editing one field inserting a single value or basing upon a formula

right click on the field name

ATTRIBUTE TABLEMultiple field editing

Field calculator

Editing all the record or only the selected ones

ATTRIBUTE TABLEMultiple field editing

Field calculator

Simply type in the new value/label

Text must be placed between quotation marks

ATTRIBUTE TABLEMultiple field editing

Field calculator

Run the calculator

ATTRIBUTE TABLEMultiple field editing

Field calculator

Entering a single value in one fieldfor all the selected records

Result

ATTRIBUTE TABLEMultiple field editing

Field calculator

Editing using formulas

Type in the formula (generally referring to another field)

ATTRIBUTE TABLEMultiple field editing

Field calculator

Editing using formulas

On the right, the available funcions for the selected type of data is listed

ATTRIBUTE TABLEMultiple field editing

Field calculator

Editing using formulas

Result

ATTRIBUTE TABLEMultiple field editing

Field calculator

Activating the “Advanced” function it is possible to make complex calculation

The VBA (Visual Basic for Application) programming language is to be used

ATTRIBUTE TABLEMultiple field editing

Field calculator

Examples of VBA scripts can be found in the help file.Internet gives the possibility to download a huge number of useful scripts for many purposes.

ATTRIBUTE TABLEMultiple field editing

Field calculator

It is possible to run the Field Calculator also outside of an Editing session;in this case, changes cannot be undone.

A warning message is shown

ATTRIBUTE TABLECalculate Geometry

It is possible to calculate gometrical features of the objects, storing them in a field of the attribute table

ATTRIBUTE TABLECalculate Geometry

Points

The only geometrical features for points are the X and Y position(i.e. the coordinates)

ATTRIBUTE TABLECalculate Geometry

Points

Add two new fieds to store the coordinates (double precision, at least 7 digist to the left of the digital point)

ATTRIBUTE TABLECalculate Geometry

Points

Right click on the field name and select “Calculate Geometry”

ATTRIBUTE TABLECalculate Geometry

PointsSelect the desired geometric property, the coordinate system and the unit

ATTRIBUTE TABLECalculate Geometry

Points

Result

ATTRIBUTE TABLECalculate Geometry

Polylines

For polylines, more properties are available:

Length,

Coords of startpoint

Coords of endpoint

Coords of centroid

ATTRIBUTE TABLECalculate Geometry

Polygons

For polygons, it is possible to calculate:

Area

Perimeter

Coords of centroid

ATTRIBUTE TABLECalculate Geometry

Polygons

For polygons, it is possible to calculate:

Area

Perimeter

Coords of centroid

ATTRIBUTE TABLEThe attribute table of every shapefile is stored as a .dbf file (i.e. as a file that can be handled by a spreadsheet, such as Excel)

ATTRIBUTE TABLEThe attribute table of every shapefile is stored as a .dbf file

ATTRIBUTE TABLEThe dbf file associated with shapefiles can be handled by a spreadsheet, such as Excel.This allows to modify, create and erase fields, make calculations and draw graphs.