Flow on Networks Hydrologic networks Linear referencing on networks Some slides in this presentation were prepared by Dr Francisco Olivera ArcGIS Resource Centers httpresourcesarcgiscom Desktop ID: 1022731
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1. Hydro Networks in GISNetwork modelFlow on NetworksHydrologic networksLinear referencing on networksSome slides in this presentation were prepared by Dr Francisco Olivera
2. ArcGIS Resource Centershttp://resources.arcgis/comDesktopHelpGetting to Readings in ArcGIS Resource Center Help for Desktop 10
3. Reading (1)ArcGIS Resource Center/Desktop 10/Help/Professional Library/Data Management/Geographic Data Types/Geometric Networks – What are geometric networks, A quick tour of geometric networks, Essential geometric networkshttp://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_are_geometric_networks/002r00000001000000/
4. Reading (2) ArcGIS Resource Center/ Desktop 10/Help/Professional Library/Guide books/Linear Referencing- What is linear referencing; Essential linear referencinghttp://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/What_is_linear_referencing/003900000001000000/
5. Key Concepts from Exercise 4"smdem" - 10 * “flowLineReclas" - 0.02 * (500 - "distance") * ("distance" < 500) Subtract 10 at all stream grid cellsSubtract an amount that tapers from 0.02*500=10 when distance is 0, to 0 when distance is 500 from streamOnly do taper when distance is less than 500, otherwise this is 0 and nothing is subtracted5005001010DEM Reconditioning as an example of quantitative raster analysisVector to RasterDistanceRaster CalculationVolume removed analysis
6. smdemsmrecondiff3D Analyst Profiles
7. Construct the Analysis LayerFillFlow DirectionFlow AccumulationStream DefinitionStream LinksCatchments
8. Convert to VectorVector streamsVector catchmentsAttribute feature with raster zonal statisticsGeometric NetworkTracing Selection statistics
9. Raster to Vector TransitionDuring the last week, you have been dealing with the flow of water through the landscape based on the raster data structuresToday we are making a transition in which we are going to use vector network data to describe water pathways. We will connect the land and water flow systems by attaching the catchments and watersheds derived from raster data processing to our vector networks
10. Four Key ConceptsFour key constructsCell to cell water movement on DEMsLine to Line water movement on networksArea flows to line (connect land and water systems – Reach Catchments)Area flows to point on line (Watershed delineation from designated points)
11. Cell Flows to a CellCore concept of flow on digital elevation models
12. Line Flows to a LineGeometric Network of NHDFlowlines
13. Area Flows to a LineReach Catchments from NHDPlusFlowline and Catchment have the same COMID
14. Area Flows to a Point on a LineWatersheds for USGS Gages
15. Network DefinitionA network is a set of edges and junctions that are topologically connected to each other.
16. Network Model in GISThree componentsGeometric model: (x,y,z,m) coordinates of edges and junctionsLogical model: which edges are connected to what junctionsAddressing model: location on the network using measure
17. Edges and JunctionsSimple feature classes: points and linesNetwork feature classes: junctions and edgesEdges can beSimple: one attribute record for a single edgeComplex: one attribute record for several edges in a linear sequenceA single edge cannot be branchedNo!!
18. Polylines and Edges
19. JunctionsJunctions exist at all points where edges joinIf necessary they are added during network building (generic junctions)Junctions can be placed on the interior of an edge e.g. stream gageAny number of point feature classes can be built into junctions on a single network
20. Connectivity TableJ124J125J123J126E1E3E2J123J124, E1J124J123, E1J125, E2J126, E3J125J124, E2J126J124, E3JunctionAdjacent Junction and EdgeThis is the “Logical Network”
21. Build Network TablesEstablishes connectivity of Edge and Junction featuresEnables tracingGenerates Generic JunctionsGeometric Network Wizard in ArcCatalog
22. Snapping Features
23.
24. Network Sources and SinksEach junctionfeature classin a network can have junctionswhich are sourcesor sinks for flowUse complex edge so that junction can be interior to edge
25. Flow to a sink
26. Flags
27. Trace Solvers
28. Upstream Trace Solvers
29. Hydrologic NetworksHydrologic data includes:Single-line streamsDouble-line streamsBraided streamsManmade channel systemsWaterbodies
30. Flow LineTraces movement of water in a one-dimensional flow system
31. Location of the Flowline
32. Introduction to the Hydro NetworkHydro Edge – think of ArcHydro Junction – think of NodeWaterbody – think of Polygon
33. Flow NetworkA connected set of flow edgesEdgeJunction
34. Network BuildingDefine flow-paths within double-line streams and waterbodies.Define network sinks and sources.
35. Network ConnectivityFind connectedFind loops
36. Network Flow DirectionEnable flow in flow-paths.Disable flow in shorelinesSinkFlow direction is unknown
37. Network Flow DirectionEnable flow in flow-paths.Disable flow in shorelinesSinkFlow direction is known
38. Uninitialized Flow Direction
39. Assigned Flow Direction
40. Network TracingTrace UpstreamTrace Downstream
41. Trace PathFind the shortest pathbetween two points on the network
42. Hydro Network for Holland
43. Hydro Network for Colorado River Basin around Lake Travis
44. Network Tracing on the Guadalupe Basin
45. Some terminologyHydrography – the mapping of water featuresBlue line features on topographic maps (streams, rivers, lakes,…)More generally, hydrography also includes the mapping of bathymetry and extent of estuaries and coastal watersNational Hydrography Dataset (NHD) – a data model for storing topographic map hydrographyMedium resolution (1:100K) is complete for USHigh resolution (1:24K) is complete for most of the USNHDPlus – a new data model integrating 1:100K resolution NHD with catchments and derived attributes from the National Elevation Dataset
46. National Hydrography DatasetFive feature classes withNHDFLowline built intoA geometric networkNHDPoint, NHDLine,NHDArea are point, lineand area water features on map apart from flowlinesand waterbodiesKey feature classes
47. National Hydrography Dataset
48. NHD Waterbody
49. NHD Geometric Network
50. NHDPlus Reach Catchments ~ 3km2About 1000 reach catchments in each 8-digit HUCAverage reach length = 2km2.3 million reaches for continental US
51. Reach AttributesSlopeElevationMean annual flowCorresponding velocityDrainage area% of upstream drainage area in different land usesStream order
52.
53. United States Experience with DEM ImprovementError in delineated watershed area5%0.5%3 arcsec: 90 m1 arcsec: 30 mDEM Cell Size1990’s2000’s
54. National Elevation Dataset for Australia9 Arc Second – 250 m1 Arc Second – 30 m1 cell81 cellsExistingNewTwo orders of magnitude improvement! Wow!Images: John Gallant, CSIRO
55. National River Network for AustraliaLine flows to LineGeometric NetworkGeometry model: Where am I? (x,y coordinates)Logical model: Who am I connected to? (topology)Addressing model: Where are things on me? (linear referencing)Image: Elizabeth McDonald, BoM
56. A challenge: those messy Aussie rivers have lots of loops and branchesImage: Michael Hutchinson, ANU
57. A fundamental innovation: Connecting the Cell to Cell and Line to Line ModelsFlow divergences have multiple flow directions on a single DEM cellImage and Research: Janet Stein, ANUCell flows to Cell
58. Reach Catchments Every stream reach has a local drainage areaArea flows to LineFundamental connection between the water and land systemsImage: Elizabeth McDonald, BoM
59. Contracted Nodes and CatchmentsContracted NodesContracted CatchmentsContracted nodes persist through successive versions of the geofabric Area flows to a point on a lineA standardized tessellation of the landscape – one chosen among the infinite number of tessellations possibleImages: Elizabeth McDonald, BoM
60. Linear ReferencingWhere are we on a line?
61. Addressing
62. Coordinates of a 2-D Polyline
63. Coordinates of a 2-D Polyline M
64. Setting Line Measure
65. Proportional AliasingDistance is measured Relative to the length of the line as a percentage0% – 100%
66. Setting Percent MeasurepMSeg.SetAndInterpolateMsBetween 0, 100 pMSeg.SetAndInterpolateMsBetween 100, 0 0 – 100 going upstream0 – 100 going downstream
67. Point and Line Events
68. Summary ConceptsFour key constructsCell to cell water movement on DEMsLine to Line water movement on networksArea flows to line (connect land and water systems – Reach Catchments)Area flows to point on line (Watershed delineation from designated points)
69. Summary Concepts (2)A network is a connected set of points (junctions) and lines (edges) that supports tracing functionsThree data model componentsGeographic (x,y,z)Logical (point-line topology connections)Addressing (position m along the line)
70. Summary Concepts (3)Linear referencing can be used to locate point and line “events” on a networkThis is like (x,y) event themes that you used earlier to map stream gage locations in geographic space