The NHDPlus data model has some shared identifiers that can span very large distances. For example, the “Level Path Identifier” identifies an entire river from headwater to outlet using the “hydrologic sequence identifier” of the outlet. Similarly, the “Terminal Path Identifier” identifies an entire basin using the hydrologic sequence identifier of the terminal flowline (to the ocean or an inland sink). When creating subsets of NHDPlus data, many times, these attributes can identify flowlines that are not included in the subset. For most applications, this is not a problem, but in some cases, it is advantageous to adjust identifiers such that the subset appears to be a complete drainage basin with a true terminal outlet. make_standalone() accomplishes this task.
On a one by one basis, this may seam insignificant, but for workflows that need to work with arbitrary subsets and start from basin outlets, this functionality is useful. It has little impact on the data and is applied by default.
The example below shows how the outlet is modified. As described in the documentation os make_standalone() all related attributes upstream are also fixed such that the network is intact for further use.
+
demo <- get_nhdplushr(hr_data_dir, layers = "NHDFlowline",
min_size_sqkm = 100, check_terminals = FALSE)
@@ -297,71 +291,69 @@
fixed_outlet <- dplyr::select(st_drop_geometry(standalone_demo_outlet),
Hydroseq, TerminalPa, TerminalFl, LevelPathI)
-print(data.frame(broken_outlet))
#> Hydroseq TerminalPa TerminalFl LevelPathI
-#> 1 22001000000414 22000100000212 0 22000300045683
-
-#> Hydroseq TerminalPa TerminalFl LevelPathI
-#> 1 22001000000414 22001000000414 1 22001000000414
-
-(broken <- dplyr::filter(demo$NHDFlowline, TerminalPa == demo_outlet$Hydroseq))
#> Simple feature collection with 0 features and 57 fields
-#> Bounding box: xmin: NA ymin: NA xmax: NA ymax: NA
-#> Geodetic CRS: NAD83
-#> # A tibble: 0 x 58
-#> # ... with 58 variables: Permanent_Identifier <chr>, FDate <dttm>,
-#> # Resolution <int>, GNIS_ID <chr>, GNIS_Name <chr>, LENGTHKM <dbl>,
-#> # REACHCODE <chr>, FlowDir <int>, WBArea_Permanent_Identifier <chr>,
-#> # FTYPE <int>, FCODE <int>, MainPath <int>, InNetwork <int>,
-#> # VisibilityFilter <int>, Shape_Length <dbl>, COMID <dbl>, VPUID <chr>,
-#> # Enabled <int>, Shape <GEOMETRY [°]>, StreamLeve <int>, StreamOrde <int>,
-#> # StreamCalc <int>, FromNode <dbl>, ToNode <dbl>, Hydroseq <dbl>,
-#> # LevelPathI <dbl>, Pathlength <dbl>, TerminalPa <dbl>, ArbolateSu <dbl>,
-#> # Divergence <int>, StartFlag <int>, TerminalFl <int>, UpLevelPat <dbl>,
-#> # UpHydroSeq <dbl>, DnLevel <int>, DnLevelPat <dbl>, DnHydroseq <dbl>,
-#> # DnMinorHyd <dbl>, DnDrainCou <int>, FromMeas <dbl>, ToMeas <dbl>,
-#> # RtnDiv <int>, Thinner <int>, VPUIn <int>, VPUOut <int>, AreaSqKM <dbl>,
-#> # TotDASqKM <dbl>, DivDASqKm <dbl>, MaxElevRaw <dbl>, MinElevRaw <dbl>,
-#> # MaxElevSmo <dbl>, MinElevSmo <dbl>, Slope <dbl>, SlopeLenKm <dbl>,
-#> # ElevFixed <int>, HWType <int>, HWNodeSqKm <dbl>, StatusFlag <chr>
-
-(standalone <- dplyr::filter(standalone_demo, TerminalPa == standalone_demo_outlet$Hydroseq))
#> Simple feature collection with 5358 features and 57 fields
-#> Geometry type: MULTILINESTRING
-#> Dimension: XY
-#> Bounding box: xmin: -90.68076 ymin: 41.27482 xmax: -88.1999 ymax: 43.74949
-#> Geodetic CRS: NAD83
-#> # A tibble: 5,358 x 58
-#> Permanent_Identi~ FDate Resolution GNIS_ID GNIS_Name LENGTHKM
-#> * <chr> <dttm> <int> <chr> <chr> <dbl>
-#> 1 156038282 2012-03-19 01:32:25 2 004155~ Pecatonica~ 1.34
-#> 2 155714162 2014-10-28 19:00:00 2 004248~ Fairfield ~ 0.417
-#> 3 156035374 2012-03-19 01:35:08 2 015619~ Gordon Cre~ 0.39
-#> 4 145600320 2012-03-19 01:34:47 2 004168~ Rock Creek 0.352
-#> 5 155712981 2012-03-19 02:05:43 2 <NA> <NA> 0.034
-#> 6 137417698 2012-03-18 13:07:30 2 015750~ Sugar River 0.798
-#> 7 156037500 2012-03-19 01:33:10 2 <NA> <NA> 0.009
-#> 8 145599800 2012-03-19 01:34:47 2 004145~ North Fork~ 0.665
-#> 9 143246785 2012-03-18 12:56:42 2 004168~ Rock River 0.165
-#> 10 155712415 2012-03-19 02:05:51 2 004241~ Willow Cre~ 2.11
-#> # ... with 5,348 more rows, and 52 more variables: REACHCODE <chr>,
-#> # FlowDir <int>, WBArea_Permanent_Identifier <chr>, FTYPE <int>, FCODE <int>,
-#> # MainPath <int>, InNetwork <int>, VisibilityFilter <int>,
-#> # Shape_Length <dbl>, COMID <dbl>, VPUID <chr>, Enabled <int>,
-#> # Shape <MULTILINESTRING [°]>, StreamLeve <int>, StreamOrde <int>,
-#> # StreamCalc <int>, FromNode <dbl>, ToNode <dbl>, Hydroseq <dbl>,
-#> # LevelPathI <dbl>, Pathlength <dbl>, TerminalPa <dbl>, ArbolateSu <dbl>,
-#> # Divergence <int>, StartFlag <int>, TerminalFl <dbl>, UpLevelPat <dbl>,
-#> # UpHydroSeq <dbl>, DnLevel <dbl>, DnLevelPat <dbl>, DnHydroseq <dbl>,
-#> # DnMinorHyd <dbl>, DnDrainCou <int>, FromMeas <dbl>, ToMeas <dbl>,
-#> # RtnDiv <int>, Thinner <int>, VPUIn <int>, VPUOut <int>, AreaSqKM <dbl>,
-#> # TotDASqKM <dbl>, DivDASqKm <dbl>, MaxElevRaw <dbl>, MinElevRaw <dbl>,
-#> # MaxElevSmo <dbl>, MinElevSmo <dbl>, Slope <dbl>, SlopeLenKm <dbl>,
-#> # ElevFixed <int>, HWType <int>, HWNodeSqKm <dbl>, StatusFlag <chr>
-
-
+print(data.frame(broken_outlet))
+#> Hydroseq TerminalPa TerminalFl LevelPathI
+#> 1 22001000000414 22000100000212 0 22000300045683
+print(data.frame(fixed_outlet))
+#> Hydroseq TerminalPa TerminalFl LevelPathI
+#> 1 22001000000414 22001000000414 1 22001000000414
+
+(broken <- dplyr::filter(demo$NHDFlowline, TerminalPa == demo_outlet$Hydroseq))
+#> Simple feature collection with 0 features and 57 fields
+#> Bounding box: xmin: NA ymin: NA xmax: NA ymax: NA
+#> Geodetic CRS: NAD83
+#> # A tibble: 0 x 58
+#> # ... with 58 variables: Permanent_Identifier <chr>, FDate <dttm>,
+#> # Resolution <int>, GNIS_ID <chr>, GNIS_Name <chr>, LENGTHKM <dbl>,
+#> # REACHCODE <chr>, FlowDir <int>, WBArea_Permanent_Identifier <chr>,
+#> # FTYPE <int>, FCODE <int>, MainPath <int>, InNetwork <int>,
+#> # VisibilityFilter <int>, Shape_Length <dbl>, COMID <dbl>, VPUID <chr>,
+#> # Enabled <int>, Shape <GEOMETRY [°]>, StreamLeve <int>, StreamOrde <int>,
+#> # StreamCalc <int>, FromNode <dbl>, ToNode <dbl>, Hydroseq <dbl>,
+#> # LevelPathI <dbl>, Pathlength <dbl>, TerminalPa <dbl>, ArbolateSu <dbl>,
+#> # Divergence <int>, StartFlag <int>, TerminalFl <int>, UpLevelPat <dbl>,
+#> # UpHydroSeq <dbl>, DnLevel <int>, DnLevelPat <dbl>, DnHydroseq <dbl>,
+#> # DnMinorHyd <dbl>, DnDrainCou <int>, FromMeas <dbl>, ToMeas <dbl>,
+#> # RtnDiv <int>, Thinner <int>, VPUIn <int>, VPUOut <int>, AreaSqKM <dbl>,
+#> # TotDASqKM <dbl>, DivDASqKm <dbl>, MaxElevRaw <dbl>, MinElevRaw <dbl>,
+#> # MaxElevSmo <dbl>, MinElevSmo <dbl>, Slope <dbl>, SlopeLenKm <dbl>,
+#> # ElevFixed <int>, HWType <int>, HWNodeSqKm <dbl>, StatusFlag <chr>
+(standalone <- dplyr::filter(standalone_demo, TerminalPa == standalone_demo_outlet$Hydroseq))
+#> Simple feature collection with 5358 features and 57 fields
+#> Geometry type: MULTILINESTRING
+#> Dimension: XY
+#> Bounding box: xmin: -90.68076 ymin: 41.27482 xmax: -88.1999 ymax: 43.74949
+#> Geodetic CRS: NAD83
+#> # A tibble: 5,358 x 58
+#> Permanent_Identi~ FDate Resolution GNIS_ID GNIS_Name LENGTHKM
+#> * <chr> <dttm> <int> <chr> <chr> <dbl>
+#> 1 156038282 2012-03-19 01:32:25 2 004155~ Pecatonica~ 1.34
+#> 2 155714162 2014-10-28 19:00:00 2 004248~ Fairfield ~ 0.417
+#> 3 156035374 2012-03-19 01:35:08 2 015619~ Gordon Cre~ 0.39
+#> 4 145600320 2012-03-19 01:34:47 2 004168~ Rock Creek 0.352
+#> 5 155712981 2012-03-19 02:05:43 2 <NA> <NA> 0.034
+#> 6 137417698 2012-03-18 13:07:30 2 015750~ Sugar River 0.798
+#> 7 156037500 2012-03-19 01:33:10 2 <NA> <NA> 0.009
+#> 8 145599800 2012-03-19 01:34:47 2 004145~ North Fork~ 0.665
+#> 9 143246785 2012-03-18 12:56:42 2 004168~ Rock River 0.165
+#> 10 155712415 2012-03-19 02:05:51 2 004241~ Willow Cre~ 2.11
+#> # ... with 5,348 more rows, and 52 more variables: REACHCODE <chr>,
+#> # FlowDir <int>, WBArea_Permanent_Identifier <chr>, FTYPE <int>, FCODE <int>,
+#> # MainPath <int>, InNetwork <int>, VisibilityFilter <int>,
+#> # Shape_Length <dbl>, COMID <dbl>, VPUID <chr>, Enabled <int>,
+#> # Shape <MULTILINESTRING [°]>, StreamLeve <int>, StreamOrde <int>,
+#> # StreamCalc <int>, FromNode <dbl>, ToNode <dbl>, Hydroseq <dbl>,
+#> # LevelPathI <dbl>, Pathlength <dbl>, TerminalPa <dbl>, ArbolateSu <dbl>,
+#> # Divergence <int>, StartFlag <int>, TerminalFl <dbl>, UpLevelPat <dbl>,
+#> # UpHydroSeq <dbl>, DnLevel <dbl>, DnLevelPat <dbl>, DnHydroseq <dbl>,
+#> # DnMinorHyd <dbl>, DnDrainCou <int>, FromMeas <dbl>, ToMeas <dbl>,
+#> # RtnDiv <int>, Thinner <int>, VPUIn <int>, VPUOut <int>, AreaSqKM <dbl>,
+#> # TotDASqKM <dbl>, DivDASqKm <dbl>, MaxElevRaw <dbl>, MinElevRaw <dbl>,
+#> # MaxElevSmo <dbl>, MinElevSmo <dbl>, Slope <dbl>, SlopeLenKm <dbl>,
+#> # ElevFixed <int>, HWType <int>, HWNodeSqKm <dbl>, StatusFlag <chr>
+
+plot(st_geometry(standalone))
