A) most of the empire is Forrest's. Not flat terrain. So row or map doesn't help there. B) row absolutely can do stuff that you couldn't without, like move troops over a marsh, or explode.
Like, if mathy could only have invented one of the two i would take map more often then not, because it's a) reliable and b) Multi-Wind castable.
Reikland: Reikwald to the north, Skrag Hills to the north, Hagercryps to the south, Grissenwald at the southern border, Marshes on the northern border, mountains and rocky terrain on the western border to the Grey Mountains, Vorbergland between the mountains and hils, being a nice area of plains. Marshes around the River Reik, particularly around Altdorf, which also includes the Bloodpine Woods and the Amber Hills.
Wissenland: A valley between the rivers Sol and Reik where most inhabitants live, incredibly rocky/hilly around the north, west, south and southeast as it approaches the Grey and Black Mountains and the Vaults.
Averland: Primarily plains and lowlands. Primary cavalry base where many horses are grazed and raised with a good environment for them. Lots of farmland, surrounded on three sides by rivers and one by mountains with a pretty wide pass as a result of volcanic activity. Has a few hills as it transitions into the other provinces.
Stirland: Primarily hilly land, with two major hill ranges in the form of the Stirhugel in the West and the Hunter Hills in the east. There are also smaller hills in the south in the Moot and one in the north around central stirland. Has a couple woods and smaller forests around the northern edges, primarily in Central and Eastern Stirland. Has lots of wetlands in Eastern Stirland (Sylvania). Turns mountaineous as it approaches the World's Edge on the south/southeast.
Ostermark: Has great plains for raising horses known as the Veldt, which is their flatest and most arable area. Otherwise, Ostermark is bordered by the World's Edge on the east, thick forests to the west/northwest/southwest in the form of the Dead Wood and Gryphon Woods, which transitions into the Shirokij in Kislev which it borders. The centre is largely dominated by hills in the form of the Bleak Moors and Eerie Downs.
Ostland: Mountaineous around the southwest as it approaches the Middle Mountains, which is where a great deal of Ostland's towns and settlements exist. Has a small connection of hills to the south around the River Talabec. Primarily forest until it transitions into plains which could perhaps be described as a Steppe between the border of Nordland to Kislev, which then transitions into the rocky coastline of the Sea of Claws.
Nordland: Southeast borders the Middle Mountains and is therefore mountaineous. Has lots of hills, although many of them are actually controlled by Laurelorn. 2/3rds Laurelorn forest. A good portion of the eastern border is part of the Forest of Shadows. What's left is largely hilly with some flat spots until it hits the coastline. Marshes exist between Nordland and Mddenland, although it would be more accurate to say between Laurelorn and Middenland.
Middenland: Marshes to the north, rocky/mountaineous around the northeast as it transitions into the Middle Mountains. Both the southeast and southwest is hilly with the Howling Hills and Midden Moors, which also happens to be pretty marshy, respectively. A great portion of it is forested, split between Drakwald and Laurelorn.
Hochland: Very hilly and mountaineous around the north, forested for the rest of it, and a good portion of the centre-east is dominated by the Weiss Hills. Flattest portion is around the rivers bordering the province.
Talabecland: Three giant hilly portions in the centre from left to right with the Barren, Farlic and Kolsa Hills. Most of the rest, including all of Talabecland's borders leading to the rivers, is the Great Forest. Some marshland exists here.
My geography primer for the Empire, outlining broad strokes of what it looks like.