1 / 22

Map-Making with the NHD

Map-Making with the NHD. Bill Wheaton Research Triangle Institute wdw@rti.org, (919) 541-6158. Mapmaking with the NHD. Topics Map Design and Layout Using NHD Content in Maps Displaying Other Data with NHD. Map Design and Layout.

maddox
Télécharger la présentation

Map-Making with the NHD

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Map-Making with the NHD Bill Wheaton Research Triangle Institute wdw@rti.org, (919) 541-6158

  2. Mapmaking with the NHD • Topics • Map Design and Layout • Using NHD Content in Maps • Displaying Other Data with NHD

  3. Map Design and Layout • Modern Tools Don’t Alleviate the Need for Proper Map Design and Layout • Who is the audience? • What is the map communicating? • What are the uses for the map? • Colors, projections, use of white space, etc.

  4. Feature Issues • What are the NHD Feature Classes? • Region.wb : Waterbodies • Region.rch : Waterbody Reaches • Region.lm : Area Landmarks • Route.drain : Network Features • Route.rch : Linear Reaches • Route.lm : Linear Landmarks • nhdpt.pat : Point features • nhdduu.patdom : Digital Update Units (quad/cu bdy)

  5. Feature Issues • Unusual Features

  6. Feature Issues • Overlapping Features • Most common between lake/ponds and 2-D reaches • Other Cases: • 2-D: • swamp/marsh and lake/pond; • foreshore and sea/ocean; • rapids and 2-d stream/river • 1-D: • Bridge, Overpass, Canal • Issue: within same feature class (drawing order issue) or different feature class (no drawing order issue)

  7. Feature Issues • Overlapping Features (continued) • How to know: • Examine the NHD.RXP file • Where poly# is duplicated, you have overlapping features • Select out RCH features, then perform a frequency…Those records with count gt 1 are overlapping. • DEMONSTRATION….

  8. Finding Overlapping 2-D Features NHD.RXP File Select All but RCH Summarize by Poly# Count gt 1 are Overlaps

  9. Feature Issues • Overlapping Features (continued) • How to symbolize: • Choose ‘see through’ symbols • OR– choose which feature you care about more • Demo...

  10. 2-D Overlaps... Submerged Stream/River Lake/Pond Foreshore Sea/Ocean

  11. Feature Issues • Artificial Paths on Coastlines… • Problems: • Around Some Islands, Not Around Others • May Not Want to See Them Anyway • How to ‘Hide’ them • Reselect Reaches Having ‘Non-Flowing’ Connections • Do Left/Right Analysis to Find APs that Have Land on One Side AP on Coast

  12. Using NHD Attributes • NHD.FCODE • Contains Every Unique Combination of Feature and Attributes • Used for Distinguishing Between Perennial and Intermittent (e.g.) • Relate by FCODE, 5-digit code present in feature tables

  13. Feature Types vs. Attributes

  14. Using the NHDDUU Coverage • Contains the “Digital Update Units” • Currently the 1:100K Quads and CU that Make Up the Dataset • NHDDUU.PATDOM : Region Feature Class Containing Those Boundaries • With Future Updates, Could be Any Geographic Area

  15. FOD-ifacts • 2-D Features that Touch CU Boundary are Not Split… • Clever Use of DUU Can Hide Them… • Mask Areas by Selecting DUU Polys • Symbolize with Background Color (white) • Draw Those Polys on Top of 2-D Features

  16. Labeling NHD Features • Names are on: • Route.RCH: streams/rivers • Region.RCH: lake/pond • Region.WB: Other 2-D waterbodies • Region.LM: Big Dams, etc. • Route.LM: Small Dams, etc. • NHDPT: Springs, Seeps, Waterfalls, etc.

  17. Handling Multiple CUs • “One at a Time” is Tedious for Large Areas • Use append_NHD (available on NHD Web Site) • AML • Initial Release or Flow Validated Inputs, but Not a Mixture • Handles Overlaps/Duplicate Features, and Other Nastiness

  18. Displaying Reaches • What’s the Point Unless You Have Additional Information Related to Them? • Displaying Events • Displaying Flow, Displaying Stream Order, etc.

  19. Projections • NHD Delivered in “non-projected”, Decimal-Degree Coordinates • Project On-the-fly or Permanently for Proper Maps

  20. Scale Issues • At Small Scales, May not Want to Show 2-D Stream/Rivers, Use Drains Only, Symbolize APs Like Stream/Rivers • Make 2-D Feature Outlines Invisible • At Very Large Scales, May See APs Outside their 2-D Features • Quad Edge Problems More Apparent at Large Scales...

  21. Using NHD with Other Sources • The Usual Issues: • Registration • Scale • Source • DRGs • DOQQs • DEM/NED

  22. Happy Mapping!

More Related