In case you were wondering what was going on in the vicinity of the spot where we’ve selected to camp out for a week, here is a map I’ve made from 3/357IR and 315FA’s battalion journals. The highlighted spot is Les Tourelles farm at Orglandes. It seems clearly situated on the German LOC. Judging by the lines drawn 15 June 1944, and the fact that German battalion mortars are about a kilometer from the line of contact (the ones that 315FA spotted anyway) it looks as if the enemy were already withdrawing from the sector by the time Sam Williams’s attack was launched. Also of note, this was the first time 343 and 315FA were able to get it together to fire preparation on Gourbesville center.
Taking out a little time to look at Grass GIS. The objective here is to do a simple (heh-heh) floodplain map for Sèves St. Germain. These are the catchment basis as calculated from SRTM30 data via QGIS/GRASS, which will serve as a basis (I hope) for a flow model. Downstream is to the north east (right in the static image. Here’s a 3D model.)
So why does an historian, even an amateur one care about land areas contributing to runoff toward a given flow? Well, this is the terrain that first and second battalions of 358IR attacked across. The plan called for crossing tanks, only there was a pretty big rainstorm in the evening. The crossing was already contested and the water high, but should have been possible the following morning. If I can track down divisional G2 meteorological information from 1944, I should be able to feed it into the model and come up with a better visualization of exactly how high the water was.
Lots of caveats here. The SRTM was taken in the 1990s and the streambed has probably changed a bit since. Metaled (paved) roads are now the norm, which changes the flow coefficients. But enough. I just want a better idea of how high the water was back then. And it is keeping with my design objective to bring as much data to this design as I can.
Click through to a manipulable 3D visualization of Le Bourg St. Léonard, the fourth battle in From the Ground Up. Terrain relief is exaggerated 30m SRTM data. The building footprints are from Open Street Map before I visually compared them with my field notes and the 1947 aerial survey photo of the IGN. The Z height of the buildings is a database merge based on my field notes and an aerial photo from 1944. This is a very preliminary model. Later on, I’ll tease out polygons for the ground cover and assign heights when I next have some time to devote to making further progress in QGIS. For the moment, I’m hammering out artillery and campaign rules.