#
Heat Map

Heat Map is the graph that uses colors to show the numbers in the table.

##
Use of Heat Map

Heat Map is used in various ways.

###
To Show Large Data Table

The tabel below is the part of 1000-10 size table.
We cannot see full of them.

Heat Map for this table is below.
The left side is made by
seaborn
.
The right side is made by R (code is below).

Colors shows numbers of the table.

If the line up of data has the meaning of space or time, heat map could be the
Graph for Change
.

###
To Show Multi Dimensional Data

If the table is the multi dimensional data. heat map is the multi dimensional graph.
Generally, 3-dimension is the limit of graphical way.
But heat map shows more than 3 dimension **easily**.

In this way, heat map can be used for the method of
Correlation Analysis for Multi-Variable
.

###
To Show 3-Dimension Data

Heat map is used to show 3-dimension data using
"X : Column, Y : Row, Z : Color".

###
To Show 2-Dimension Data

If we make frequency or density data by the range in the X and Y,
heat map is used as
Histogram
of 2D.
And it covers the weakness of
2-Dimension Scatter Plot
.

##
By R

**setwd("C:/Rtest")** # Change directory

**Data <- read.csv("Data.csv", header=T)** # Input data

**DataM <- as.matrix(Data)** # Make data as matrix

**heatmap(DataM, Colv = NA, Rowv = NA)** # Make heat map

If the last code is

**heatmap(DataM)**

,
Cluster Analysis
is done.

NEXT Graphs for 2-Dimension Distribution and Relationship