[SHOM-IGN] Coastline _ Histolitt®

The coastline corresponds to the high seas leash in the case of an astronomical tide of 120 coefficient and under normal weather conditions (no offshore wind, no atmospheric depression likely to raise sea level). The TCH product models this theoretical entity by a set of 2D polylines. The TCH is composed of elements from: — elements from TC25000. The TC25000 is the result of digitisation by a Marine Card operator at scales greater than 1/25000. In some port areas, maps on scales of 1/5000 have been used. For the area of the coast of Les Landes, only maps on 1/50000 are available. The charts used are taken from the SHOM portfolio of 1992. The SHOM Marine Chart Coastline uses: 1. photogrammetric restitution of the SHOM 2. Topographical Minutes 3. IGN cards at 1/25 000 — elements of the class [leashbone] of the product BDTopo®Pays version 1.2 whose value of the attribute ‘NATURE’ is ‘High seas’. — elements entered in 2D on background BDOrtho® image. The process is to update the TC25000 from TCBDTOPO and BDOrtho® product. The result obtained is the TCH. The most up-to-date versions of TCBDTOPO and BDOrtho® at the date of this production process have been used. On the occasion of this process, the topology was built: continuity of the TCH which is nevertheless cut into several polylines into remarkable points of the rib line. The islands represented in a surface form are closed polylines. The sections of identical attributes are merged.