I am trying out a slightly different format for this post. Instead of attempting to describe everything in the text and being forced to use clunky directional adjectives (ex: "200 m south-west of the western-most garage), I am now directly annotating the screenshots from Google-Earth which will hopefully allow a much more precise analysis of imagery.
The 81st armored division is based in Iran's Kermanshah province on their border with Iraq. Naturally they were among the first forces to come into contact with the invading Iraqi army in 1980. At the outbreak of the war, their three brigades in Kermanshah, Sarpol-e Zahab and Eslamabad Gharb were outfitted with Chieftain MBTs and M113 APCs. (1) Today the situation is less clear; some evidence suggests that one of these brigades has been moved to a base nearer to Kermanshah in Bistoon. (2)
There are, however, two unaccounted-for armored brigades in Eslamabad Gharb, and in Sarab Ghale Shahin. While they most likely belong to the IRGC's 4th ID(3), it is extremely unusual that an infantry division would be so heavily mechanized. One distinguishing feature unique to these two bases compared to their Artesh equivalents is that they all appear to be undergoing some form of construction during the mid-2000s, typically centered around garages. Another possibility (however unlikely), is that the Artesh's armored divisions are much stronger than previously imagined and what we're seeing is merely the 81st AD.
All three brigades are co-located on the east-west Road 48 that leads to the Iraqi border.
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The divisional HQ is located on northern side of the Road 48 leading east out of the city. The compound can be identified as belonging to the 81st division because of the markings on a small hill facing the highway which reads "Artesh".
On the far-eastern side of the motor-pool is a large battalion - 38 - of BMP IFVs (#9 on the map). Although the size of this formation more closely mirrors a BTR battalion (which we've seen on parade in Kermanshah), the dimensions and appearance are more similar to a BMP. Even though they all appear to be BMPs, there are differences between the IFVs in the western-most column and the rest of the vehicles. Though the following cannot be confirmed, this may be a difference between the visually similar BMP-1 and BMP-2.
North of the motor-pool are a wide array of firing ranges and fighting positions. In between the motor-pool and the firing ranges are a handful of concrete ramps dug into the earth with tracks leading to and from them. It is unclear what the purpose of such a feature is but it may be to practice quick movement to and from firing positions; a tactic we know to involve underground ramps thanks to imagery from exercises. They can be found in armored brigades across the province which makes it a fairly distinctive feature.
Although Bistoon is described as the divisional HQ, the configuration and relative sizes of each compound points to the lion's share of 81st division's assets being based out of Kermanshah as there are several distinct administrative and support sections which are absent at Bistoon. One explanation is that Kermanshah is the former divisional headquarters (which is supported by the historical record) and that the facilities at Bistoon are more recent and as of yet underdeveloped.
One of these areas in question is marked #12 on the map. It contains a number of "T" shaped buildings which are common at military compounds across the country and are usually associated with garrison facilities. It also includes a number of long, narrow barracks-like buildings, motor-pools with tractor-trailers and parade yards. Combined with the fact that the compound sits outside the entry-control point for the main base, this evidence may indicate that it functions in some sort of separate capacity to the 2nd brigade. This is purse supposition however.
An army aviation facility is also located in Kermanshah.
Smaller than either the garrisons in Bistoon or Kermanshah, the compound at Sarpol-e Zahab is rather atypical. Rather then having a rigid organization, buildings here are often small and clustered in disorganized patterns. There are three main types of buildings, a) large, flat-roofed structures; at least a few may be garages or wharehouses, b) multi-winged, flat-roofed buildings; may be barracks, and c) brick/mud buildings with domed roofs similar to buildings at the 1st brigade HQs for the 88th AD in Zahedan. Entering the compound, there are four main clusters of buildings that the roads lead to, two on either side of the main road.
(3) While the IRGC has since been reorganized, doing away with the numbered system of brigades and divisions, the imagery dates from before this shift in force structure. Compiled from various sources during the Open Source Intelligence Project.