Editing Indirect fire (section)

==Related issues==
[[File:USMC-081021-M-0007C-008.jpg|thumbnail|right| A [[USMC|United States Marine]] [[lance corporal]] plots the direction and elevation of a [[mortar (weapon)|mortar]] before firing.]]
Before a gun or launcher can be aimed, it must be oriented towards a known [[azimuth]], or at least towards a target area. Initially, the angle between the aiming point and target area is deduced, or estimated, and set on the [[azimuth sight]]. Each gun is then laid on the aiming point, with this angle in order to keep them aimed roughly parallel to each other. However, for [[artillery]] another instrument, called either a director (United Kingdom) or [[aiming circle]] (United States), became widespread and eventually the primary method of orienting guns in most if not all armies. After being oriented and pointed in the required direction a gun recorded angles to one or more aiming points. Such early directors were the progenitors of the later general class of [[director (military)|directors]].

Indirect fire needs a command and control arrangement to allot guns to targets and direct their fire. The latter may involve ground or air observers or technical devices and systems. Observers report where shots fall so that aim may be corrected. In the First World War an important task for aircraft — both heavier-than-air or balloons — was [[artillery spotting]]. In naval use several ships may be shooting at the same target, making identifying the fall of shot from a particular ship difficult; different-coloured dyes for each ship were often used to help with spotting.<ref>{{Cite web |title=Definitions and Information about Naval Guns - Ammunition Definitions - Splash Colors|last=DiGiulian |first=Tony |website=NavWeaps |date=2 March 2021 |url= http://www.navweaps.com/Weapons/Gun_Data_p2.php}}</ref>

Fire may be "adjusted" or "predicted". Adjusting (originally "ranging") means some form of observation is used to correct the fall of shot onto the target; this may be required for several possible reasons:
* geospatial relationship between gun and target is not accurately known;
* good quality data for prevailing conditions is unavailable; or
* the target is moving or expected to move.

[[Predicted fire]], originally called "map shooting", was introduced in World War I. It means that firing data is calculated to include corrections for the current prevailing conditions. It requires the target location to be precisely known relative to the gun location.

Adjusted and predicted fire are not mutually exclusive, the former may use predicted data and the latter may need adjusting in some circumstances.

There are two approaches to the azimuth that orients the guns of a battery for indirect fire. Originally "zero", meaning 6400 mils, 360 degrees or their equivalent, was set at whatever the direction the oriented gun was pointed. Firing data was a deflection or switch from this zero.

The other method was to set the sight at the actual grid bearing in which the gun was oriented, and firing data was the actual bearing to the target. The latter reduces sources of mistakes and made it easier to check that the guns were correctly laid. By the late 1950s, most armies had adopted the bearing method, the notable exception being the United States.