WMS:Importing Shapefiles

ARC/INFO® or ArcView® shape files provide the easiest method to import GIS data into WMS. Unfortunately the shape file format is extremely redundant, meaning that points or lines that are shared by lines or polygons are multiply defined.

Therefore, in order for you to convert a shape file to a WMS coverage it may take up to several minutes (depending on size) to build the correct line or polygon topology. This was very problematic in previous versions because WMS often bogged down when reading moderately large files. This is one of the primary reasons that the GIS module was developed and with or without a license to ArcObjects shapefile data can now be managed better by WMS.

With the addition of the GIS module there are now two different ways to import shapefile data.

Direct Conversion of Shapefile Data to Coverages

The first is the traditional method which allows you to load a shapefile layer (or a point, line, and polygon shapefile layer in the case of the drainage coverage) directly into a coverage, using the File | Open command.

You can then map attribute fields of the shapefiles database (.dbf) file to their pertinent WMS parameters (some key words are automatically recognized as listed in the table below.

Using the GIS Module to Convert Shapefile Data to Coverages

When opening a shapefile in the GIS module using the Add Shapefile Data or Add Data commands WMS first reads the points/lines/polygons into a simple display list and does not try to "build" topology by connecting arcs at nodes, and eliminating shared edges of polygons as required when creating a coverage. This makes the display and selection of the polygons much easier and more efficient. You can then select only the polygons you wish to convert to a coverage and map them. In this way you will only be building topology for the selected polygons.

Cleaning Imported Shapefile Data

If you intend to use the data from the shape file in more than one session you should save it as a WMS map file after importing/mapping the first time. Further, after importing the shape files you may wish to consider the following:

• Clean the feature objects in order to snap nodes within a certain distance, intersect arcs, and eliminate dangling arcs.

• Reorder Streams for arcs which will be used as stream arcs. WMS requires that the direction of an arc (from-node to to-node) be from “downstream” to “upstream.”

• Build Polygon so that WMS can define the topologic tree used for hydrologic modeling. After intersection of arcs, reordering of streams, etc. it is often necessary to rebuild the polygon topology so that the topologic structure is consistent with the tree used for hydrologic modeling.

Key Words for Automatic Mapping of Attributes

The following key words are used to automatically map shapefile (dbase or .dbf) attribute field names to data within WMS.

Keyword names to map Shape file attribute item names to WMS variables:

Parameter	Name	Description/Possible Values
Point Attributes
Drainage Point type*	draintype	0=generic 1=link break 2=weir 3=bridge 4=culvert 5=outlet point
Temrminus Combine name	comname	HEC-1 terminus name
Terminus Route name	rtename	HEC-1 route name
LA County reach type	la_type
LA County reach location	la_loc
LA County reach lateral	la_lateral
LA County reach slope	la_slope
LA County reach length	la_length
LA County reach n	la_n
LA County reach side n	la_siden
LA County reach slope	la_sideslp
LA County reach depth	la_depth
LA County reach channel def	la_chdef
LA County reach char width	la_charw
LA County reach velocity	la_vel
LA County reach detail	la_detail
LA County reach hydrograph	la_hydrog
LA County reach input hydrograph	la_inhydro
LA County reach input hydrograph area	la_inharea
LA County reach relief	la_relief
LA County reach trap	la_trap
LA County reachsize	la_size
LA County reach capacity	la_capc
LA County reach bulked flow	la_bulkedf
LA County reach reservoir routing	la_resrt
LA County reach initial pool elev	la_initp
LA County reach street width	la_streetw
LA County reach reach curb height	la_curbh
GSSHA Point type	casctype	GSSHA point type: 0 = generic 1 = link break 2 = hydraulic structure (weir) 3 = bridge 4 = culvert 11 = dynamic well 12 = static well 13 = constant head 14 = river head 15 = rating curve 16 = rule curve 17 = scheduled discharge 24 = GSSHA low point 25 = GSSHA oulet
Link id	linkid	Link id
Free flow coefficient	ffcoeff	Free flow coefficient
Crest width	crestwid	Crest width
Crest elevation	crestelev	Crest elevation
Flooded coefficient	floodcoef	Flooded coefficient
Gage depth	gagedepth	Rain gage depth for gage coverage
Z coordinate	elevation	This changes the Z-coordinate of the point
Arc Attributes
Drainage arc type*	draintype	0 = Generic 2 = Ridge 3 = Stream 32 = Lake 44 = Pipe
GSSHA arc type	casctype	GSSHA arc type: 0 = Generic 1 = Trapezoidal channel 3 = General stream 8 = Cross section channel 12 = Trapezoidal channel (Groundwater process enabled) 13 = Cross section channel (Groundwater process enabled) 30 = Trapezoidal channel (Sediment process enabled) 31 = Trapezoidal channel (Sediment and groundwater processes enabled) 42 = Embankment 45 = Pipe
Link ID	linkid	GSSHA Link ID
Manning's	cmannings	GSSHA Manning's "n" value
Bottom width	bwidth	GSSHA bottom width
Channel depth	chdepth	GSSHA channel depth
Side slope	sideslope	GSSHA side slope
M River	mriver	GSSHA M-River value
K River	kriver	GSSHA K-River value
Arc Elevation	elevation	Arc point elevation
Flood barrier elevation	fbelev	Flood barrier elevation
SWMM name	swmmname	SWMM link name
SWMM shape	swmmshape	SWMM link shape options: "Circular" "Rectangular" "User defined" "Special" "Trapezoidal" "Power Fn." "Natural"
SWMM diameter	swmmdiameter	SWMM link height/diameter
SWMM length	swmmlength	SWMM link length
SWMM upstream invert	swmmupinvert	SWMM link upstream invert elevation
SWMM downstream invert	swmmdninvert	SWMM link downstream invert elevation
Polygon Attributes
Drainage polygon type*	draintype	Drainage polygon type: 0 = generic 1 = boundary 2 = lake
Drainage basin id	basinid	Drainage basin id (integer)
sub-basin area	basinarea	Basin area (float)
sub-basin slope	basinslop	Average slope within the sub-basin (float)
sub-basin maximum flow distance	mfdist	Max flow path, including overland and stream flow (float)
sub-basin max flow distance slope	mfdslope	Slope along the max flow path as defined above (float)
sub-basin distance to centroid	centdist	Distance from centroid to closest point on main channel (float)
sub-basin stream centroid to outlet	centout	Distance from point in stream closest to centroid to outlet (float)
sub-basin slope from centroid to outlet	slcentout	Slope along the distance defined above (float)
sub-basin percent southfacing	psouth	Percentage of area facing south, 0.0-1.0 (float)
sub-basin percent northfacing	pnorth	Percent of area facing north, 0.0-1.0 (float)
sub-basin maximum stream length	mstdist	The longest stream distance within the basin (float)
sub-basin maximum stream slope	mstslope	The slope along the longest stream distance (float)
sub-basin length	basinlen	Distance to furthest point along basin perimeter (float)
sub-basin shape factor	shapefact	Basin length divided by basin area (float)
sub-basin sinuosity factor	sinuosity	Maximum stream length divided by basin length (float)
sub-basin perimeter	perimeter	Perimeter of basin (float)
sub-basin average elevation	meanelev	Average elevation (float)
sub-basin centroid	centroidx	Basin centroid, closest point in basin if centroid is outside of the basin (X-coord) (float)
sub-basin centroid	centroidy	Basin centroid, closest point in basin if centroid is outside of the basin (Y-coord) (float)
sub-basin name	basinname	Basin name (string)
sub-basin lagtime	lagtime	Lag time, in Hours (float)
sub-basin time of concentration	tc	Time of Concentration, in hours (float)
sub-basin SCS curve number	cn	SCS Curve number computed from hydrologic soil type and land use (Integer)
sub-basin initial abstraction	ia	Initial abstraction used for the HEC-1 Green and Ampt method
sub-basin volumetric moisture deficit	dtheta	Volumetric moisture deficit used for the HEC-1 Green and Ampt method
sub-basin wetting front suction	psif	Wetting front suction used for the HEC-1 Green and Ampt method
sub-basin hydraulic conductivity	xksat	Hydraulic conductivity used for the HEC-1 Green and Ampt method
sub-basin percent impervious	rtimp	Percent impervious used for the HEC-1 Green and Ampt method
sub-basin Maricopa County adjusted slope	adjslope	Maricopa County adjusted slope for computing Clark Tc and R values
sub-basin Clark R value	clarkr	Clark R value for the HEC-1 Clark unit hydrograph method
sub-basin average precipitation	precip	Basin average precipitation, in inches (float)
sub-basin LA County lateral	la_lateral	LA County lateral
sub-basin LA County location	la_loc	LA County location
sub-basin LA County rainfall depth	la_raind	LA County rainfall depth
sub-basin LA County Tc	la_tc	LA County Tc
sub-basin LA County percent impervious	la_imprv	LA County percent impervious
sub-basin LA County soil number	la_soil	LA County soil number
sub-basin LA County basin hydrograph	la_hydrog	LA County basin hydrograph
sub-basin LA County basin bulked flow	la_bulkedf	LA County basin bulked flow
landuse	lu_code	Land use code from the SCS land use table. Possible values range from 0-127
Land use join ID	mu_code	Land use join ID
Percent impervious	imperv_	LA County percent impervious
soil type	hydgrp	SCS Soil type, A, B, C, or D or 0, 1, 2, or 3
soil type (LA County)	class	LA County soil type
sub-basin rainfall depth	rainfall	Rainfall depth
runoff coefficient, C	runoffc	Rational method runoff coefficient, C (float)
GSSHA polygon type	casctype	GSSHA polygon type: 0 = Generic 1 = Boundary 2 = Lake 3 = No Boundary 4 = Wetland
GSSHA leakage discharge	ldis	GSSHA leakage discharge
GSSHA spillway width	spwidth	GSSHA spillway width
GSSHA discharge coefficient	discoeff	GSSHA discharge coefficient
GSSHA water elevation	welev	GSSHA water elevation
GSSHA spillway crest	spillcres	GSSHA spillway crest
Rainfall zone ID	rnzone_	Rainfall zone ID
Rainfall zone name	name	Rainfall zone name
DPA zone	dpa_zones	DPA zone
Flood area	fexarea	Flood area
Flood depth	fexdepth	Flood depth
Flood class ID	fexcid	Flood class ID
Flood class name	fexcname	Flood class name
NFF state	state	NFF state (2-letter state abbreviation, e.g. UT = Utah)
NFF state's region	nff_region	NFF region in state

^* means this is essential to import into WMS and create a watershed model directly. The three essential items are point, arc, and polygon types. The general stream arc should be used to represent a stream in a watershed model. The boundary polygon type should be used to represent a polygon boundary. The outlet point type should be used to represent a watershed outlet or sub-basin outlet point.

In order to import shapefile attributes into WMS and build a tree automatically, the following conditions must be met:

1. A point coverage containing watershed and sub-basin outlets with the appropriate type (outlet point) attribute defined must exist.
2. An arc, or line, coverage containing streams in the watershed with the appropriate type (general stream) attribute defined must exist.
3. A polygon coverage containing watershed boundaries must exist.
4. There cannot be any overlapping arcs.
5. Stream arcs must be created from the downstream to the upstream node for all stream arcs.

If a data value in the shapefile corresponds to a WMS variable but it is not defined with the appropriate keyword it can be mapped manually using the Attribute Mapping dialog. One item from the database fields window is selected and the corresponding coverage attribute field is also identified. Finally, the Map button is selected to define a new mapped attribute. The Unmap button can be used to remove a pair of mapped fields.

Related Topics:

• Supported WMS File Formats
• Feature Object Guidelines
• GIS Module
• Mapping GIS Layer Data to Feature Objects