1. The NHD for the Trinity River Basin: Appending CUs and Linear Referencing
November 28th, 2000
Kristina Schneider

2. Introduction Study Area & Focus Area NHD Workspaces The Append Aml
Linear Referencing
Summary

3. Study Area: The Trinity River Basin
Focus Area

4. Feature Attribute Table
NHD Workspaces
Spatial Data Set
Contents
Feature Attribute Table
Coverage: NHD
Route DRAIN
Network Element Theme
NHD.RATDRAIN
Route RCH
Transport and Coastline Reach Theme
NHD.RATRCH
Route LM
Line Landmark Theme
NHD.RATLM
Region WB
Waterbody Theme
NHD.PATWB
Region RCH
Waterbody Reach Theme
NHD.PATRCH
Region LM
Area Landmark Theme
NHD.PATLM
Nodes
NHD underpass features exist on some nodes
NHD.NAT
Coverage: NHDPT
Points
Point Landmark Theme
NHDPT.PAT
Coverage: NHDDUU
Region.dom
Digital Update Unit Theme
NHDDUU.PATDOM
Have a Complex Integrated Data Structure
3 Route Systems
3 Region Systems
3 Route System
Drain : route subclass theme
Rch: Transport: pathway for flow in a drainage network & Coastline: represents a coastline, segments of a surface water with similar hydrologic characteristics
LM: Landmark Features are shown here. Ex. Walls, Tunnels, Gates, Bridges
3 Region Systems
WB: regions of areal waterbody features
RCH: reaches consist of more that one waterbody region, way in which to relate additional information to the waterbody
LM: Area landmarks: induation zones, bays, inlets, hazards zone

5. The Append Aml What is Aml? What is the purpose of the Append Aml?
Arc Marco Language
What is the purpose of the Append Aml?
Integration of Adjacent NHD Workspaces
Removal of Duplicate Information
Marcos are used in GIS as they are used in any other program, to simplify processing and to perform calculations and other activities that would other wise be too time consuming.  
It can combine up to 500 NHDinArc workspaces into a single workspace.

6. &run append_nhd area_test batch huc_input.txt
The Append Aml
How do we use Append?
Verify Data has been unzipped correctly
Use the program
&run append_nhd area_test batch huc_input.txt
The program is available from the NHD website
Be sure to use Winzip 8.0 or above or another zipping program
The reason is that in some Cus some datasets are 0k files because they are empty
Must use a program that unzipps a 0k file because Append requires that all basic data sets are available
Name the coverage you would like to create
Batch or browse – like batch better (just have to create txt file in the folder that contains append)
Running time will be about 25 minutes for 2 CUS and more for others

7. Append Results
Is there a difference between Appended Networks and Unappended Networks?

9. Comparison of Appended & Unappended Cus
Unappend CUs
Attributes
3930
3932
Network
Traced
3830
3831
Notes about values: They still need to be verified

10. Linear Addressing Types of General Linear Addressing
Absolute Addressing
Relative Addressing
Linear Addressing on the NHD
3 Route systems but only 1 Linear Referencing system Reach Routes
Absolute: In meters, actual distance
Relative: As a percentage of the total distance

11. Measures on the NHD
Measured in an order that opposes the direction of the coordinates
Relative Measure
Linear Reaches: Any ordinary reach in river
Discontinuous Reaches: Occur in Swamps/marches, It is bit hard to see but the pond that is connected to this reach is disconnected from the main stem.
Branched reaches: Occur in water bodies
When there are 2 or more inflows and/or 2 or more outflows

12. Where are we on the River?
Use the Editor toolbar in ArcInfo 8.1
Click on the desired reach and right
click onto
Properties
This what will come up in the properties

13. Where are we on the River?
Decide on which points to reference.
Create a table in ArcCatolog for the points.
In ArcMap enter in m-values already found using the Editor.
Create an Event Table and Display the Route Events
Points: Note M value Rch_com_id, other needed information

14. Example Results on the Trinity
Found two rapids in the focus area and decided to follow the procedure explained before
They are at the same measures, locally since I created one from the other
A word of caution, when creating the table for the events be sure to allow the m-value to carry decimal places.
The Route Events are located at the same measures as the Originals.

15. Summary
Successfully implemented the Append Aml on the focus area of the NHD.
Compared Appended and Unappended Networks.
Explored Linear Addressing on the NHD.
Verified a methodology to create Route Events from the NHD point Coverage.