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

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

Study Area: The Trinity River Basin Focus Area

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

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.  

&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

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

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

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

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

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

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

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.

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.