The map draws the model from the document and edits it with the toolbar's tools. It is drawn from caches rebuilt whenever the document's text changes, and those caches come only from the document, so the map and the file can never disagree.
The symbols follow the EPA SWMM GUI: a junction is a circle, an outfall a triangle, a storage unit a rectangle, a divider a diamond, a rain gage a drop. A conduit is a line with a direction arrow when View → Flow Arrows is on; a pump, orifice, weir or outlet is a line marked with its symbol at the midpoint. A subcatchment is a filled outline with a dashed line from its centroid to its outlet. Labels are text at a position, optionally anchored to a node.
Objects with no [COORDINATES] row cannot be drawn and
are reported by the validator
(no [COORDINATES] row, so it cannot be drawn). See chapter 16.
| Tool | Key | What it does |
|---|---|---|
| Select | S |
Click selects; Shift-click adds; Ctrl-click toggles; drag moves the selection or, from empty space, rubber-bands a box. |
| Pan | H |
Drag to pan. The wheel zooms in every tool. |
| Zoom + | + |
Click to zoom in on a point. |
| Zoom − | - |
Click to zoom out from a point. |
| Zoom Win | Z |
Drag a rectangle to zoom to it. |
| Gage | R |
Click to place a rain gage. |
| Subcatch | A |
Click each corner; double-click, Enter, or click the first corner to close; Esc cancels. |
| Junction | J |
Click to place. |
| Outfall | O |
Click to place. |
| Divider | D |
Click to place. |
| Storage | T |
Click to place. |
| Conduit | C |
Click the start node, click to add vertices, click the end node; Esc cancels. |
| Pump | P |
As Conduit. |
| Orifice | I |
As Conduit. |
| Weir | W |
As Conduit. |
| Outlet | U |
As Conduit. |
| Label | L |
Click where the label goes; a Label text prompt asks for the text. |
The letter keys work only when no text field has the keyboard.
Esc in order: cancels a profile pick, then an in-progress
gesture, then clears the selection, then returns to Select.
F fits the whole model; Delete removes the
selection.
A new object is one undo step and follows the EPA GUI's defaults for a new object:
J, invert 0, MaxDepth 0 (the engine then uses the highest
connecting conduit crown), InitDepth 0, SurDepth 0, Aponded 0. Outfall
prefix O, divider D, storage
ST.C; the length you drew
in map units (minimum 1), Manning's n 0.01, offsets 0, InitFlow 0,
MaxFlow 0; an [XSECTIONS] row CIRCULAR 1. Pump
prefix P (ideal pump, curve *, ON); orifice
OR (SIDE, 0.65); weir W; outlet
OL.S; the model's
first rain gage; the node nearest the polygon's centroid as outlet; area
5, 25 % impervious, width 500, slope 0.5 %; a [SUBAREAS]
row (n 0.01/0.1, storage 0.05/0.05, 25 % zero, OUTLET) and an
[INFILTRATION] row whose columns follow
[OPTIONS] INFILTRATION (Horton, Green-Ampt or Curve
Number); a [POLYGONS] row per corner.R; INTENSITY, 1:00,
SCF 1.0, TIMESERIES with the model's first series or
*.Numbers are in the model's units, whatever FLOW_UNITS
says. Nothing is converted.
Vertex chosen — drag it, or press Delete); drag it,
or Delete removes that vertex rather than the object.Object snap (toolbar, or View → Snap to Objects) snaps a placed point, a link end or a polygon corner to a nearby node. Grid snap snaps to multiples of the spacing shown next to the checkbox (in map units). View → Grid draws the grid. Neither changes existing coordinates.
Right-click on the map:
| Item | On |
|---|---|
| Zoom Extents | anywhere |
| Zoom To | an object |
| Edit Properties… | an object — shows the Properties sheet |
| Attribute Table… | an object — opens its section's table |
| Profile from Here… | a node — then click the end node; Esc cancels |
| Reverse Link | a link — swaps From and To and reverses its vertices, so the drawn line is unchanged and the flow direction flips. The in/out offsets are not swapped; check them afterwards |
| Convert Node Type | a node — rewrites its row as a junction, outfall, divider or storage unit with that layout's defaults, keeping the name, invert and coordinates; links and subcatchments still point at it |
| Delete | the selection |
Ctrl+C, Ctrl+X, Ctrl+V and the
Edit menu. Pasted objects get new unique names; links between two pasted
nodes are pasted with them; the paste is offset by a fraction of the
model's extent so it does not land on the original. One undo step.
Delete removes the selection. When a node goes, so do
its links, and a subcatchment draining to it is left with a dangling
outlet the validator reports. Before doing that the Delete takes
more with it dialog names the links and the subcatchments it would
orphan; Delete all of it or Keep them. One undo step
either way.
Two different things sit under the map.
The backdrop (View → Backdrop) is SWMM's own: a PNG
or JPEG placed in model coordinates and kept in the .inp's
[BACKDROP] section, so it travels with the model and the
EPA GUI shows it too.
.pgw for PNG, .jgw for JPEG, or
.wld) sits beside it, the image is georeferenced from it at
once (Backdrop site.png placed from site.pgw); otherwise
the status bar says to place it by hand..pgw/.jgw beside the image so the next load is
automatic. OK writes FILE, DIMENSIONS,
UNITS, OFFSET and SCALING to
[BACKDROP] as one undo step.A world file's rotation terms are ignored with a note: SWMM cannot draw a rotated backdrop. Lengths are never measured from the picture; see Compute Conduit Lengths below.
Map Dimensions… (View menu) edits
[MAP] DIMENSIONS — the map's extent as the EPA GUI records
it — with Set from model (the drawn objects' extent
with 6 % room) and Set from backdrop, and
[MAP] Units (None, Feet, Meters, Degrees). StormSewer's own
view always fits to the objects; the dimensions matter to the EPA GUI
and to the length factor.
Underlays (File → Load PNG Background…, File → DXF
Underlay…) are the storm-sewer workspace's drawing aids, placed by their
own width scaling and offset, not stored in the .inp, with
their opacity and Remove buttons in the Layers tab. Use the backdrop for
anything that should survive in the model file.
Drawing a conduit writes its drawn length once (§3.3). Moving a node afterwards
does not change Length; nothing recomputes on its own.
Project → Compute Conduit Lengths… does it on request:
[MAP] Units and
FLOW_UNITS (map feet to model feet is 1; feet to metres
0.3048; metres to feet 3.28084; DEGREES is not a length and
you must set the factor yourself; no Units line assumes map
units are model units), and can be typed over;[CONDUITS]
as one undo step.The status bar shows, left to right: the active tool and its key
(Tool: Select (S)); the pointer's model coordinates;
undo N, the number of steps that can be undone; the tool's
hint; and the last file message.
The line under the map, Validation: …, is the live
referential check over the document (chapter 16 lists what it checks). It
reads no findings, or counts errors and warnings; click it
to list them, click a finding to select and zoom to its object. Project
→ Validate Model does the same from the menu. Errors refuse a run;
warnings do not.
note.Length changes only when you draw
a conduit or run Compute Conduit Lengths (§3.10).