Distribution Units Craig Johnston NHD Plus Training Series Objectives Understand how NHDPlusV2 data is organized and distributed Using the context of NHDPlusV2 processing and distribution units ID: 723411
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NHDPlusV2 Processing and Distribution UnitsCraig Johnston
NHDPlus Training SeriesSlide2
ObjectivesUnderstand how NHDPlusV2 data is organized and distributedUsing the context of NHDPlusV2 processing and distribution units:Review where to obtain NHDPlusV2 dataReview the NHDPlus directory structureLearn about the BoundaryUnit shapefile1ObjectivesSlide3
AgendaDrainage areasVector Processing Unit (VPU)Raster Processing Unit (RPU)Directory StructureGlobal Data BoundaryUnit2AgendaSlide4
NHDPlusV2 is Distributed by Major Drainage Areas of the United States Drainage areas3Slide5
Drainage areasVector Processing Unit (VPU)Raster Processing Unit (RPU)Within each Drainage AreaNHDPlusV2 data componentsare packaged by:4Slide6
Vector Processing Units (VPU) Vector Processing Units (VPU)of NHDPlusV2A Drainage Area is composed of one or more VPUsMississippi, Colorado, and South Atlantic Drainage Areas have multiple VPUsVector data and attribute tables are distributed at the VPU level. NHDPlus Catchment grid also distributed as one file for each VPU5Slide7
NHDPlus Vector Processing Units (VPU)of the Major Drainage Areas6Slide8
7VPUs are shown on the NHD
PlusV2Data access website7Slide9
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NHDPlus
Version 2.1
Drainage area ID
VPU ID
Component
Name_vv
vv
= data content version
for component
NHDPlusV2 Distribution Filename Key
VPU 07
Upper Mississippi
NHD
Plus
V2 data components
by VPU
packaged
as compressed files
Vector Processing Units (VPU)
8Slide10
Note: The catchment grid is distributed at the VPU levelRaster Processing Units (RPU) Raster Processing Units (RPU)of NHDPlusV2A VPU is composed of one or more RPUsRaster data for a VPU is divided by RPU areas and distributed at the RPU levelHydroDEMFdr and Fac gridsFdrNullFilledAreasNED SnapshotCatseed9Slide11
10NHDPlus V2 Raster Processing Units (RPU) nested in VPUs of the Major Drainage Areas10Slide12
11Data Components for RPUs are accessible from the NHDPlusV2 Data downloadwebsite for the associated VPU11Slide13
12
NHDPlus
Version 2.1
Drainage area ID
VPU ID
Component
Name_vv
vv
= data content version
for component
NHDPlusV2 Distribution Filename Key
RPU ID
Elev_cm
grid
from the
NED Snapshot data component
07c
07b
07a
NHD
Plus
V2 data components by RPU
packaged as compressed files
Raster Processing Units (RPU)
12Slide14
NHDPlusV21/Drainage Area WorkspacesDirectory Structure at the highest levelDrainage Area WorkspacesDirectory structure13Slide15
NHDPlusV21/NHDPlusMS/Within each Drainage Area workspace are the VPU workspacesVPU Workspaces for theMississippi (MS) Drainage AreaDirectory structure within a Drainage AreaWorkspaceDirectory structure14Slide16
15NHDPlusV21/NHDPlusMS/NHDPlus07
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RPU workspaces
V
PU workspaces
VPU and RPU Data Component folders for the Upper Mississippi VPU 07
Directory structure
Directory Structure within a VPU workspace
VPU and RPU folders
15Slide17
Click here to download NHDPlusV21_NHDPlusGlobalData Drainage Areas, VPU, and RPU boundaries are available from the NHDPlus “Global” LinkNHDPlus: Global Data16Slide18
NHDPlusV21/NHDPlusGlobalDataContains overlapping geometry for VPU and RPU boundariesWhen adding BoundaryUnit.shpto ArcMap, the boundaries show the VPUs, however RPU boundaries are also included in this shapefileBoundaryUnit.shpGlobal Data Boundary Unit17Slide19
Example Query Expressions for BoundaryUnit.shp"DrainageID" = 'MS' AND "UnitType" = 'VPU'Select all VPUs in the Mississippi Drainage Area"UnitType" = ‘RPU'Select all RPUs
"UnitID" LIKE '17%' AND "UnitType" = 'RPU''Find all RPUsin VPU17
Global Data Boundary Unit18Slide20
ResourcesAdditional information on NHDPlus is available from the NHDPlus website documentation page. You are encouraged to read and reference the NHDPlusV21 User Guide and other NHDPlus documentation.The NHDPlus team maintains a user email list and periodically sends emails regarding new tools, data, documentation, and events. If you would like to be on the user list, send an email to nhdplus-support@epa.govThe NHDPlus team also provides technical support to users of the data and tools. If you have a technical support question, please send a detailed email to nhdplus-support@epa.gov19Slide21
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