What is isometric drawing & Process and instrumentation drawing?

Isometric drawing is a method for visually representing three-dimensional objects in two dimensions in technical and engineering drawing.

P&ID is a flow diagram which indicates general flow of of plant process and equipments

Isometric dwg is for fabrication & P&ID dwg are  for erection 

Isometric Drawing have the accurate length and path ,but in the P&ID Drawing only having the path from where to where the pipe line connection,and also showing the instruments which are on those pipe line connection

Drawing made on 45 degree. three dimentional drawing and schematic drawing.

isometric drawing is a way to presenting drawings in a three dimensions.

process/instrumentation drawing are more Details and show up the way the process to install or produce somthing.mostly 2D with lettering

ISOMETRIC 3D

P&ID 2D DRAWING WITH MORE DETAILS,DIMENSIONS,....ETC