COMPNENTS OF ARCGIS•ArcGIS is a collection of software products for building complete geographic information systems (GIS).

•Unlike other versions of Environmental Systems Research Institute (ESRI) GIS software (e.g., ArcView 3.x), ArcGIS 8 and 9 provide an integrated GIS, combining object-oriented and traditional file-based data models with a set of tools to create and work with geographic data.

•The ArcGIS software suite comprises the following three applications:

ARCMAP ARCTOOLBOX ARCCATALOG

ARCMAP

ARCTOOLBOX

ARCCATALOG

MAP PROJECTIONS

Because the earth is round and maps are flat, getting information from a curved surface to a flat one involves a mathematical formula called a map projection, or simply a projection.

This process of flattening the earth will cause distortions in one or more of the following spatial properties: •Distance •Area •Shape •Direction

No projection can preserve all these properties; as a result, all flat maps are distorted to some degree. Fortunately, you can choose from many different map projections. Each is distinguished by its suitability for representing a particular portion and amount of the earth's surface and by its ability to preserve distance, area, shape, or direction. Some map projections minimize distortion in one property at the expense of another, while others strive to balance the overall distortion. As a mapmaker, you can decide which properties are most important and choose a projection that suits your needs.

South America in selected projections at identical scale.

Types of projections

Generally classified by the spatial attribute they preserve Conformal maintains shape

Example - Lambert Conformal Conic Equal-area maintains area

Example - Albers Equal Area Conic Equidistant maintains distance

Example - Equidistant Conic Direction or Azimuthal maintains some directions

Example - Lambert Equal Area Azimuthal

PROJECTION & COODINATES

Different Projections have different coordinates for same location.

LONGITUDE LATITUDE X Y X Y1 Kottayam 76.52423669 9.585246694 667275.7428 1059927.031 -659272.2305 1101497.8772 Palghat 76.63742928 10.79925088 679021.8264 1194262.057 -641711.5903 1235630.013 Trivandram 76.95270319 8.486958605 714963.3132 938673.2964 -616387.9774 977468.16134 Kozhikhode 75.78122822 11.2465035 585275.1335 1243349.052 -733237.4846 1288870.1065 Kannur 75.36752129 11.87188879 540027.0798 1312413.824 -775186.5924 1359904.746 Palai 76.68192972 9.711659029 684517.2912 1073989.727 -641357.2963 1114880.2137 Allepy 76.32811431 9.483577245 645791.7395 1048594.286 -681346.8733 1091045.9848 Ollyar 76.23832022 10.4871652 635517.2297 1159542.574 -686767.1882 1202784.59 Trichur 76.207717 10.513224 632156.581 1162411.401 -690004.9711 1205806.129

10 Mattancheri 76.24668109 9.952482646 636660.6592 1100415.805 -688236.2508 1143474.62411 Ernakulam 76.29098788 9.969122808 641511.1421 1102274.633 -683288.6962 1145125.44612 Quilon[Kollam] 76.59515972 8.886040009 675406.6178 982630.3632 -654407.3743 1023416.477

LCCTOWNNAMESNO

GEOGRAPHIC UTM

From the above table its very clear that only coordinate information will not be sufficient to plot the points on the map. We need to have coordinate & the corresponding projection information to correctly plot the features on the map.

PROJECTION TOOLS There will be 2 tools that will be frequently used in

Projection.• Define Projection• Project

• Define ProjectionDefine projection will assign the projection

information to a given file. Before assigning a projection the user must be aware of coordinates of the file so that the correct projection is assigned.

The projection information will be stored in the file after the projection is defined & the same can be checked in the properties of the file or in the Metadata.

• ProjectThis tool will be used to change from one projection to another projection.

This tool will ask for a input file ( projection must be already defined for the input file ), output file & the output file’s projection.

• Exercise on Define Projection & Project tools

SPATIAL DATA REPRESENTATION

Vector data

Raster data

Rows

Co

lum

ns

X,YX,Y

X,YX,Y X,Y

X,Y

X,Y

Two common data structures: Vector and Raster

Real world Vector (points, lines, and polygons)

Raster (grid cells)

SPATIAL DATA FORMATS ArcGIS can work with spatial data in multiple formats

CAD

Coverage

Geodatabase

Shapefile

Raster Tables

ArcGIS

DATA FORMATS – SHAPE FILE

Single feature class Attributes stored in dBASE table

Donutshapefile

Shapefile .dbf table

• Exercise – Display Shape file through Windows Explorer. File Renaming etc

DATA FORMATS – COVERAGE A folder containing multiple feature classes

Can store point, line, polygon feature classes, and more

Attributes stored in a separate INFO table

landusecovcoverage

Coverage INFO table

• Exercise – Display Coverage through Windows Explorer

DATA FORMATS – GEODATABASE Stores spatial features and their attributes in the same RDBMS

Feature classes can be stand-alone or grouped in a feature dataset

Feature datasets model spatial relationships

RDBMS table

Coffeegeodatabasefeature class

Municipalfeature dataset

• Exercise – Display Geodatabase through Windows Explorer

DATA FORMATS – CAD FILES (DWG, DGN ETC) Computer Aided Design files (DXF, DWG, DGN)

Logical collection Access one or all feature class(es) at a time

Edit after conversion to coverage or geodatabase feature class

CAD file (read-only attribute tables)

• Exercise – Open Cad file in ARCMAP

DATA FORMATS – TABLES Table to point feature class

Table with raw coordinates

Table with addressesNew feature class

New feature class

DATA FORMATS – IMAGES & GRIDS Rows and columns of equal-sized cells

Each cell stores a value Detail depends on cell size

Grids (the ESRI native raster format)

Images (tiff, bmp, sid, jpeg, ERDAS)

• Exercise – Display Grid & IMG in ARCMAP

• NOTE : - The details of the file format can be seen in the Metadata of the corresponding file

ATTRIBUTE TABLE

Descriptive information about features

Each feature class has an associated table

One row for each geographic feature

Right-click

ATTRIBUTE TABLE - PROPERTIES

Basic table properties Records/rows and fields/columns Column types can store numbers, text, dates Unique column names

Columns

RowsAttributevalues

ATTRIBUTE TABLE - PROPERTIES Different field types store different kinds of values

Choose the right field type for the right value

Field types vary according to table format

Name: Jupiter

Moons: 16

Diameter: 142,984 km

Date of Comet Shoemaker-Levy impact: 7/16/1994

Rotation period: 9.8 hr

Text Date Short Long Float

Jupiter 7/16/1994 16 142984 9.8

ATTRIBUTE TABLE - MANIPULATION Open table in ArcMap or preview in ArcCatalog

Sort ascending or descending Freeze/Unfreeze columns Statistics

In ArcMap

Select records

Modify table values

ATTRIBUTE TABLE – ADD FIELD Open table in ArcMap

Click on Options Button Select Add field Option

Add field window appears

Enter Field Name Select the field type Update the field properties as required. Click OK.

ATTRIBUTE TABLE – CALCULATE VALUES Open Attribute table in ArcMap

Right On the field in which the attribute to be updated.

Select Calculate Values

Field Calculator window appears, enter the data to be updated in field calculator. There are 3 major ways of calculating the attributes.

Calculate the attributes with a fixed value / data

This will update all the records in the Statename field as “Punjab”

Calculate the attributes with respect to the data available in other field

In this the user has to select an existing field. In the above case the data available in TOWNCODE field will be updated in CODE field

Calculate the attributes using functions

This will update the values available DICTRICTNA field into Proper case

Some of the points to remember while calculating values If any records are already selected in the attribute table, calculated data will be updated only to the selected

records If no records are selected in the attribute table, calculated data will be updated to all the records in the

attribute table. Other than SDE featureclass, records can be calculated without going into editing mode. Before calculating, ensure that the right value is being calculated, records to be updated for selected

records or all the records. Because you can’t undo the calculate values operation if the updation was done in non editing mode.

During calculate operation the operator must be aware on the data type of the field which is being updated i.e. the operator shouldn’t try to updated TEXT values in a numeric field or while updating a TEXT field the values must be given within a double quotes ( “ ” ).

ATTRIBUTE TABLE – CALCULATE VALUES, POINTS TO REMEMBER

• Exercise : - • Create Fields and try updating attributes as show in the Slide “ATTRIBUTE TABLE -

PROPERTIES“• Calculate values using all the 3 types of updation.

SELECTION BASED ON ATTRIBUTES Open attribute table in ArcMap

Click on Options Button Select By Attributes option

Use an SQL statement to select features

Save and reload selection expressions SELECTION METHOD

• Exercise : - Perform attribute query using various logical operators & selection method

SUMMERIZE ATTRIBUTES Open Attribute table in ArcMap

Right On the field to be summarized.

Select summarize option

Summarize window appears

FIELD BEING SUMMARIZED

OUTPUT FILE HAVING THE SUMMERIZED RESULT

DETAILS REQUIRED BY USER IN OUTPUT

ON SELECTING THIS OPTION, DATA WILL BE SUMMARIZED FOR SELECTED RECORDS ONLY

This option allows a table of summary information to be generated for the fields in the selected table. Unique values from a specified field are used as a basis for the summary information.

• Exercise : - Given the Villages of Punjab with Census 2001 data. Generate a District wise report containing the details like Number of villages, Total Population in the District, Max & Min village population in that district, average village population.

STATISTICS

Open Attribute table in Arc Map

Right On the field for which the statistics to be seen.

This can be performed on Numeric Fields only

A window containing the statistics of the selected field appears as shown below.

Statistics will provide, how many values the column has, as well as the sum, minimum, mean, maximum, and standard deviation of those values. A histogram is also provided showing how the column's values are distributed. Statistics are calculated for all numeric columns in the table.

JOIN – FROM TABLES

Add the Layers / Tables in ARCMAP

Right On the Layers / Tables which is to be joined.

Select Joins & Relate Join

A Join data table window appears.

Joining involves appending fields (items) of one table to those of another through an attributes or field common to both tables. A join is usually used to attach more attributes to the attribute table of a geographic layer

Join Data Table appears

Select Join attribute from a table option.

Chose the common field in the Input file

Chose the Layer / Table to be joined

Chose the common field in the join file

• Click on Advanced button

• Select options like “Keep All Records” or “Keep Only Matching Records”

• Type of outputs on selecting each option is shown below

• Exercise : - Join attributes of Census 2001 data with Village locations

JOIN – BASED ON SPATIAL LOCATION

• Exercise : -• Transfer the Attributes of available in the Taluka Boundary to the the village Points.• Identify the Nearest Railway Station & National Highway for the Given villages. Then conclude which is the

nearest ( NH or Railway Station )

The process remains similar till to the “Join – From Tables” till “Join Data Table appears”. Once the Join Data Table appears, follow the steps mentioned below

Select “Join data from another Layer” option.

Chose the Layer to be joined

Chose the Spatial Join Options

Output File containing the Result

THE OUTPUT DEPENDS ON THE TYPE OF SPATIAL JOIN OPTION SELECTED

Join based on spatial location Find the nearest feature Find what's inside a polygon Find what intersects a feature

Appends attributes and calculates distance

RELATE Define relationship between two tables. Tables remain independent

Add the Layers / Tables in ARCMAP

Right On the Layers / Tables which is to be related.

Select Joins & Relate Relate

A Relate window appears.

COMMON FIELD IN THE INPUT FILE

COMMON FIELD IN RELATE FILE

RELATE FILE

RELATE NAME

Open related table

• Exercise : - Provided City Boundary & Pincode Boundaries. Compare these layers & generate a report having cities not having pincode boundaries, cities not having city boundaries & cities having both.

Point-in-polygon Line-in-polygon Polygon-on-polygon

Different from select by location

Overlay layer

Output layer inherits overlay layer’s attributes

Input layer

OVERLAY ANALYSIS

OVERLAY ANALYSIS - INTERSECT

Computes a geometric intersection of the input features. Features or portion of features common to all layers and/or feature classes will be written to the output.

• Exercise : - Provided Reserve forest Boundary Layer, Proposed Pipeline Layer & Area for proposed pipeline layer. Find out the area of land covered in Reserve Forest for the proposed pipeline.

OVERLAY ANALYSIS - UNION

Computes a geometric intersection of the input features. Features or portion of features common to all layers and/or feature classes will be written to the output.

• Exercise : - Provided Landuse Layer & Slope Layer, identify Areas with Landuse as Open Space & Slope Class as 1

OVERLAY ANALYSIS - CLIP

Computes a geometric intersection of the input features. Features or portion of features common to all layers and/or feature classes will be written to the output.

• Exercise : - Provided Several Layers of Hyderabad City, the user requires the data only for Begumpet Pin code Boundary.

DISSOLVE

Computes a geometric intersection of the input features. Features or portion of features common to all layers and/or feature classes will be written to the output.

• Exercise : - Provided Village Boundaries of Kerela containing Taluka & District names, generate Taluka & District Boundaries Layer.