Introduction to attributes in ArcGIS

1. Introduction to Attributes
Prof. Dr. Sajid Rashid Ahmad
sajidpu@yahoo.com
Atiqa Ijaz Khan _ Demonstrator
atiqa_ss09@yahoo.com

2. Intro to Attributes
• “Non-spatial information about a geographic feature in a GIS, usually stored in a
table and linked to the feature by a unique identifier.” (ESRI)
• Attributes defines how information that specifies a particular feature will be
displayed and labeled on a map.
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3. Examples
• For vectors:
• It is usually associated back-end information, like, name, population, length, width, etc.
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4. Examples
• For raster:
• Each cell associated with unique properties like rainfall, temperature, slope, etc.
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5. Who ‘ll define the image?
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6. Types of Attributes
• Following are the types of attributes that are used in Arc GIS data fields:
• Number
• Text
• Date/Time
• BLOB (Binary Large Object)
• GUIDs (Globally Unique Identifiers)
• Geometry
• Raster
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ArcGIS data type Access data type Notes
OBJECTID Long Integer OBJECTID is an AutoNumber field.
SHORT INTEGER Integer
LONG INTEGER Long Integer
FLOAT Single
DOUBLE Double
TEXT Text
DATE Date/Time
BLOB OLE Object*
GUID Number Replication ID, duplicates allowed
GEOMETRY OLE Object*
RASTER Long Integer
*OLE: Object Linking and Embedding: That are created in other applications and then linked with database.

8. Numbers
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• One can store numbers in one of four numeric data types:
• Short integer
• Long integer
• Float (single-precision floating-point numbers)
• Double (double-precision floating-point numbers)
• One has to chose between:
• Whole numbers and fractional
• Long or short integer
• Double or float

9. 9 Data type Storable range Size (Bytes) Applications
Short integer -32,768 to 32,767 2
Numeric values without
fractional values within
specific range; coded
values
Long integer
-2,147,483,648 to
2,147,483,647
4
Numeric values without
fractional values within
specific range
Float (single-precision
floating-point number)
approximately -3.4E38 to
1.2E38
4
Numeric values with
fractional values within
specific range
Double (double-precision
floating-point
number)
approximately -2.2E308 to
1.8E308
8
Numeric values with
fractional values within
specific range
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10. • If you just need to store whole numbers, such as 12 or 12,345,678, specify a
short or long integer. If you need to store fractional numbers that have decimal
places, such as 0.23 or 1234.5678, specify a float or a double.
• If you need to store integers between -32,768 and 32,767 only, specify the short
integer data type, because it takes up only 2 bytes, whereas the long integer data
type takes up 4.
• If you need to store fractional numbers between -3.4E38 and 1.2E38 only, specify
the float data type, because it takes up 4 bytes, whereas the double data type
takes up 8.
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11. Text
• A text field represents a series of alphanumeric symbols. This can include street
names, attribute properties, or other textual description.
• The characters used for text vary by language.
• To allow text to more easily convert between languages, ArcGIS uses Unicode to
encode characters.
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12. Date/Time
• The date data type can store dates, times, or dates and times.
• The default format in which the information is presented is:
• mm/dd/yyyy hh:mm:ss and
• a specification of AM or PM.
• When you enter date fields in the table through ArcGIS, they are converted to this
format.
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13. BLOB
• A BLOB is data stored as a long sequence of binary numbers.
• ArcGIS stores annotation and dimensions as BLOBs, and items such as images,
multimedia, or bits of code can be stored in this type of field.
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14. Geometry
• In ArcGIS, the geometry data type indicates
the type of geometry:
point, line, polygon, multipoint, or multi-patch
• The field stored as geometry type is called SHAPE
when created through ArcGIS.
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15. Precision and Scale
Specifying the precision and scale allows one to restrict the range of values and
number formats a field can accept, giving one a greater control.
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16. • Precision:
• Defines the overall field length.
• Scale:
• Defines the decimal values.
• These properties are associated with Numeric fields.
• In all of the sub-fields of numbers (i.e. float, double etc), these two properties
have to be defined with each of them.
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Serial No. Data Type Precision Scale
01. Short Integer 1-5 0
02. Long Integer 6-10 0
03. Double 1-6
04. Float 7+ 0+

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Range Data type
Precision (field
length)
Scale (decimal
places)
0 to 99 Short integer 2 0
-99 to 99* Short integer 3 0
0 to 32,767* Short integer 5 0
32,768 to 99,999 Long integer 5 0
0.001 to 0.999 Float 4 3
1,000.00 to 9,999.99 Float 6 2
-123,456.78 to 0* Double 9 2
0 to 1,234.56789 Double 9 5
* Negative numbers require additional precision to store the sign

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