# Digitization, Symbology, Export Symbology, Clip Vector Analysis Tool and Summarize in Attribute

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## Digitization

It is a process of converting information into digital format. If we have a raster file and need to extract information from that, we will do digitize for that. Digitization mainly a vector-oriented process.

There are three tools for digitization purpose

• Point – For single feature like electric pole, ATM etc.
• Line – For continuous feature like railway, road etc.
• Polygon – For discrete but large areal feature like buildings, forest, agricultural land etc.

## Symbology

• Symbols are used to design a map or visualization purpose of a map. Whenever we make a map styles and symbology plays important role for representation.
• Each mapping elements or features like point, line and polygon have individual identity of representation, for that purpose styles and symbols are used which are varied by color, size, texture etc.

## Export Symbology

A symbol file always has the extension of “. lyr” file that is represented as a Layer file. If we export the symbols of a feature class, we can use it by importing the data as per our necessity.

## Clip Vector Analysis Tool

For the vector analysis part, mainly for extraction purpose there are some tools present in ESRI Arc GIS software, are as Clip, Extract, Select etc. Clip tool (analysis) is mainly used for cutting or extract the area of interest from a feature class.

## Summarize in Attribute

On the basis of any field of the attribute table, we can summarize the data in Database table format. We can use it for calculation purpose.

## Statistics

The statistics gives the overview of the particular field of the attribute, such as mean, max, min etc.

## Calculate Geometry

We use this function basically to calculate the area of a vector file of given several units.

## Field Calculator

It is used to calculate the whole field or column with a particular single attribute.

## Structured Query Language

• A SQL represents to build a query expression in the attributes of a database. In Arc GIS, queries are made in “Select by Attribute” window with standard query language. These expressions are used to operate or perform within a database layer or table records.
• The SQL is mainly used to working with large number of datasets, are feasible with numbers, characters etc. Even people can make own query expression in Arc GIS SQL with proper knowledge.

## The Definition Query in Arc GIS

One of the very important SQL part is “Definition Query” , through which the desired added data can be appeared only in the view bar. If we added a big or large amount of dataset, but our working portion is very limited then we can delimit it with the definition query in the view bar. The definition queries are the SQL, with the help of it we make our queries.

• Very first we know about the information of the layers.
• The source file of the added layer
• The Turn off or on layer
• The selectable and non-selectable layer
• Lastly the viewing properties of the added layers

## Buffer

This is a proximity vector analysis tool to measure the affected area or specified certain covered area with predefined boundary. This tool can work in different feature datasets like point, line and polygon.

## Intersect

This is a mapping overlay tool to perform the selection and extract the information of the overlaying or intersecting part of two or more features.

## Union

It is also a mapping overlay tool that adds or combines two different datasets or features into a single feature. With the help of this tool the data from all the layers are included, meaning the overlapping and non-overlapping areas.

## Merge

Merge tool use when there are multiple features as input sources that need to be combined or merged into one feature class with the identity in the attributes.

## Georeferencing

Georeferencing means adding geographic or spatial information to an image or dataset. With the help of georeferencing we are able to place the dataset into the physical world; it simply gives the location identity. To solve a real-world problem and give it appropriate solution, the location must be needed of a dataset.

## Image to Image Georeferencing

Image to image georeferencing is one of important type of georeferencing. When we have a dataset having no coordinates with the help of a master image, we can give spatial reference to the unknown image or dataset.

Manishika