Generation of STNnetwork from flow accumulation grid and flow direction grid
(process used for generation of Gulf of Maine 1 min STNnetwork)
Data used - Hydro1k
1) Creation of sub -basin grid to guide STN development from flow accumulation grid.
-In RGIS:
1) IMPORTed Lambert projection flow direction grid (hydro1k dataset)
2) Created Virtual Station Locations using ANALYSE->STATION LOCATION subbasin area = 50
km2, tolerance = 10%
3) LINKed virtual station coverage to network
4) Ran STN CHARACTERISTICS for station coverage
5) Ran SUBBASIN function to create grid of subbasins associated with stations
-EXPORT subbasin grid to arcinfo
-Project in geographic coordinate system
-EXPORT geo_subbasin grid to RGIS
2) Resampling of Flow Accumulation grid to preserve flow values (ArcInfo)
g_fa15sec=project(g_fawin,na_lanbert_geo,nearest,[calc 0.25/60])
g_05sec=project(g_fawin,na_lambert_geo,nearest,[calc 5/3600])
remove arc_insterted null values
g_fa15secwin=setnull(g_fa15sec == 0, g_fa15sec * -1)
aggregate flow accumulation to imin resolution, keeping high values
g_Fa1min = aggregate(g_fa15secwin,4,min)
(for 5sec) g2_fa1min = aggregate(g_05secwin,12,min)
gridascii g_fa1min
import to RGIS
3) Link subbasin to flow accumulation grid, CREATE NETWORK
Edit network if necessary to remove fragmented basins (partial river networks).