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Trinity River Network Development

Trinity River Network Development. Kim Davis 6 MAY 1999. Outline. Data Needs Methods Results Conclusions. Modified Trinity River RF3 Jona Finndís. Data Used. SWQM Stations TNRCC. TMDL Segments TNRCC. Methods. Create Network Connectivity Test (Arc/Info) Topology (Dr. Olivera)

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Trinity River Network Development

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  1. Trinity River Network Development Kim Davis 6 MAY 1999

  2. Outline • Data Needs • Methods • Results • Conclusions

  3. Modified Trinity River RF3 Jona Finndís Data Used • SWQM Stations • TNRCC • TMDL Segments • TNRCC

  4. Methods • Create Network • Connectivity Test (Arc/Info) • Topology (Dr. Olivera) • Orientation • Attach Points (Richard Gu) • Dynamic Segmentation • RIT-Reach Indexing Tool

  5. Trial and Lots of Errors Nothing worked right until I re-performed this step!!! Lowered the tolerance value for network simplification (to preserve detail) Connectivity Test Arc/Info traces paths that flow to outlet Branches that are connected can be displayed Create Network

  6. Create Network • Topology • Gives each stream a unique number • Gives each stream intersection a unique number • Allows streams to have an orientation (upstream v. downstream)

  7. Create Network • Orientation • Based on Topology • Too slow! • Memory Intensive

  8. Orientation Based on Topology Based on DEM Too many flat spots Hard to error-check Create Network

  9. Create Network • Orientation • Based on Topology • Based on DEM • Back to Topology • Used a different way of ‘looking up’ streams • Easy to error-check

  10. Create Network • Attach Points • Small errorsmake points falloff the stream • Attach them without changingtheir position--create “virtualpoints”

  11. Dynamic Segmentation • Useful for properties that change with distance on a line

  12. Dynamic Segmentation • What on earth is it? • A way to display spatial information without having to store the spatial data • A flexible way to show the characteristics of spatial data

  13. Dynamic Segmentation • What that last bit meant • Every GIS map has a table of data with it • Dynamic Segmentation makes it possible to make the table smaller • You can display the data spatially without storing the shapes

  14. Dynamic Segmentation This column is what makes the map draw in GIS

  15. Dynamic Segmentation These columns allow the following spatial display of this non-spatial data

  16. Dynamic Segmentation • A line shape in a GIS table can only have one value assigned along its length. • Example: a reach 5 miles long can only store a single velocity value • That line can be dynamically segmented to store values at various points along its length

  17. Results • Topologically coherent dendritic river network with attached points and dynamic segmentation of (some) TMDL segments

  18. Conclusions • We have the basis of a good set of network manipulation tools • Future work • Exploiting dynamic segmentation • Error-checking current work • Points • Orientation

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