Study Area Map in SWMM5
| SWMM's Main Window |
SWMM's main window is pictured below. Click on a labeled element to learn more about it.
| Map Toolbar |
The Map Toolbar contains buttons for viewing the Study Area Map.
| Selects an object on the Map | |
| Selects link or subcatchment vertex points | |
| Selects a region on the Map | |
| Pans across the Map | |
| Zooms in on the Map | |
| Zooms out on the Map | |
| Draws the Map at full extent | |
| Measures a length or area on the Map |
| Types of Objects |
SWMM contains both physical objects that can appear on its Study Area Map, and non-physical objects that encompass design, loading, and operational information. These objects, which are listed in the Project Browser, consist of the following:
| · | Project Title/Notes |
| · | Nodes | ||||
| · | Project Title/Notes | ||||||||
| · | Nodes | ||||||||
| · | Simulation Options |
| · | Links | ||||
| · | Simulation Options | ||||||||
| · | Links | ||||||||
| · | Climatology |
| · | Transects | ||||
| · | Climatology | ||||||||
| · | Transects | ||||||||
| · | Rain Gages |
| · | Control Rules | ||||
| · | Rain Gages | ||||||||
| · | Control Rules | ||||||||
| · | Subcatchments |
| · | Pollutants | ||||
| · | Subcatchments | ||||||||
| · | Pollutants | ||||||||
| · | Aquifers |
| · | Land Uses | ||||
| · | Aquifers | ||||||||
| · | Land Uses | ||||||||
| · | Snow Packs |
| · | Curves | ||||
| · | Snow Packs | ||||||||
| · | Curves | ||||||||
| · | Unit Hydrographs |
| · | Time Series | ||||
| · | Unit Hydrographs | ||||||||
| · | Time Series | ||||||||
| · | LID Controls |
| · | Time Patterns | ||||
| · | LID Controls | ||||||||
| · | Time Patterns | ||||||||
| · | Map Labels | |||||||
| · | Map Labels |
| Visual Objects |
The figure below depicts how a collection of SWMM's visual objects might be arranged together to represent a stormwater drainage system. These objects can be displayed on a map in the SWMM workspace. Click on the name of any object to view its description.
| Working with the Map |
EPA SWMM can display a map of the study area being modeled. This section describes how you can manipulate this map to enhance your visualization of the system.
A Map Query identifies objects on the study area map that meet a specific criterion (e.g., nodes that flood, links with velocity below 2 ft/sec, etc.). It can also identify which subcatchments have LID controls and which nodes have external inflows.To submit a map query:
| 1. | Select a time period in which to query the map from the Map Browser. |
| 2. | Select View >> Query from the Main Menu or click the |
| 3. | Fill in the following information in the Query dialog that appears: |
| · | Select whether to search for Subcatchments, Nodes, Links, LID Subcatchments, or Inflow Nodes. |
| · | Select a parameter to query or the type of LID or inflow to locate. |
| · | Select the appropriate operator: Above, Below, or Equals. |
| · | Enter a value to compare against. |
| 4. | Click the Go button. The number of objects that meet the criterion will be displayed in the Query dialog and each such object will be highlighted on the Study Area Map. |
| 5. | As a new time period is selected in the Map Browser, the query results are automatically updated. |
| 6. | You can submit another query using the dialog box or close it by clicking the button in the upper right corner. |
After the Query dialog is closed the map will revert back to its original display.
| Setting Map Display Options |
The Map Options dialog is used to change the appearance of the Study Area Map. There are several ways to invoke it:
| · | select Tools >> Map Display Options from the Main Menu or, |
| · | click the |
| · | right click on any empty portion of the map and select Options from the popup menu that appears. |
A Map Options dialog will appear where you can set various display options, such as subcatchment fill style, node and link size, flow direction arrows, and background color.
| Setting the Map Dimensions |
The physical dimensions of the map can be defined so that map coordinates can be properly scaled to the computer's video display.
To set the map's dimensions:
| 1. | Select View >> Dimensions from the Main Menu. |
| 2. | Enter coordinates for the lower-left and upper-right corners of the map into the Map Dimensions dialog that appears or click the Auto-Size button to automatically set the dimensions based on the coordinates of the objects currently included in the map. |
| 3. | Select the distance units to use for these coordinates. |
| 4. | If the Auto-Length option is in effect, check the "Re-compute all lengths and areas" box if you would like SWMM to re-calculate all conduit lengths and subcatchment areas under the new set of map dimensions. |
| 5. | Click the OK button to resize the map. |
| If you are going to use a backdrop image with the automatic distance and area calculation feature, then it is recommended that you set the map dimensions immediately after creating a new project. Map distance units can be different from conduit length units. The latter (feet or meters) depend on whether flow rates are expressed in US or metric units. SWMM will automatically convert units if necessary. |
| If you just want to re-compute conduit lengths and subcatchment areas without changing the map's dimensions, then just check the Re-compute Lengths and Areas box and leave the coordinate boxes as they are. |
| Resizing a Backdrop Image |
To resize a backdrop image select View >> Backdrop >> Resize from the Main Menu. A Backdrop Dimensions dialog will appear that allows you to specify X,Y coordinates for the lower left and upper right corners of the backdrop image. In addition, you can specify that the backdrop be resized to fit the current dimensions of the Study Area Map or that the map have its dimensions changed to match those of the backdrop. Note that with the latter option all objects currently on the map will have their coordinates changed so that their position relative to the lower left corner of the map is maintained.
| Status Bar |
The Status Bar appears at the bottom of SWMM's Main Window and is divided into six sections:
Auto-Length
Indicates whether the automatic computation of conduit lengths and subcatchment areas is turned on or off. The setting can be changed by clicking the drop down arrow.
Indicates whether the positions of links above the invert of their connecting nodes are expressed as a Depth above the node invert or as the Elevation of the offset. Click the drop down arrow to change this option. If changed, a dialog box will appear asking if all existing offsets in the current project should be changed or not (i.e., convert Depth offsets to Elevation offsets or Elevation offsets to Depth offsets, depending on the option selected).
Flow Units
Displays the current flow units that are in effect. Click the drop down arrow to change the choice of flow units. Selecting a US flow unit means that all other quantities will be expressed in US units, while choosing a metric flow unit will force all quantities to be expressed in metric units. The units of previously entered data are not automatically adjusted if the unit system is changed.
Run Status
| results are not available because no simulation has been run yet | |
| results are up to date | |
| results are out of date because project data have changed. | |
| results are not available because the last simulation had errors |
Zoom Level
Displays the current zoom level for the Study Area Map (100% is full scale).
XY Location
Displays the Study Area Map coordinates of the current position of the mouse pointer.
| Setting Map Display Options |
The Map Options dialog is used to change the appearance of the Study Area Map. There are several ways to invoke it:
| · | select Tools >> Map Display Options from the Main Menu or, |
| · | click the |
| · | right click on any empty portion of the map and select Options from the popup menu that appears. |
A Map Options dialog will appear where you can set various display options, such as subcatchment fill style, node and link size, flow direction arrows, and background color.
| Backdrop Dimensions Dialog |
The Backdrop Dimensions dialog is used to change the dimensions of the Backdrop Image imposed over the Study Area Map.
Lower Left Coordinates
Enter the X,Y coordinates of the lower left corner of the backdrop image.
Upper Right Coordinates
Enter the X,Y coordinates of the upper right corner of the backdrop image.
Resize Backdrop Image Only
Select this button if only the backdrop, and not the Study Area Map, should be resized according to the coordinates specified in the dialog.
Scale Backdrop Image to Map
Select this button to position the backdrop image in the center of the Study Area Map and have it resized to fill the display window without changing its aspect ratio. The map's lower left and upper right coordinates will be placed in the data entry fields for the backdrop coordinates, and these fields will become disabled.
Scale Map to Backdrop Image
Select this button to make the dimensions of the map coincide with the dimensions being set for the backdrop image. Note that this option will change the coordinates of all objects currently on the map so that their positions relative to one another remain unchanged.
| Backdrop Image Selector Dialog |
The Backdrop Image Selector dialog is used to select an image file to use as a Backdrop Image behind the Study Area Map. It contains the following data fields:
Backdrop Image File
Enter the name of the file that contains the image. You can click the button to bring up a standard Windows file selection dialog from which you can search for the image file.
World Coordinates File
If a "world" file exists for the image, enter its name here, or click the button to search for it. A world file contains geo-referencing information for the image and can be created from the software that produced the image file or by using a text editor. It contains six lines with the following information:
| Line 1: | real world width of a pixel in the horizontal direction. |
| Line 2: | X rotation parameter (not used). |
| Line 3: | Y rotation parameter (not used). |
| Line 4: | negative of the real world height of a pixel in the vertical direction. |
| Line 5: | real world X coordinate of the upper left corner of the image. |
| Line 6: | real world Y coordinate of the upper left corner of the image. |
If no world file is specified, then the backdrop will be scaled to fit into the center of the map display window.
Scale Map to Backdrop Image
This option is only available when a world file has been specified. Selecting it forces the dimensions of the Study Area Map to coincide with those of the backdrop image. In addition, all existing objects on the map will have their coordinates adjusted so that they appear within the new map dimensions yet maintain their relative positions to one another. Selecting this option may then require that the backdrop be re-aligned so that its position relative to the drainage area objects is correct (see Aligning a Backdrop Image).
| Aligning a Backdrop Image |
To align a backdrop image with the drainage system schematic on the Study Area Map:
| 1. | Select View >> Backdrop >> Align from the Main Menu. |
Move the backdrop image across the Study Area Map by moving the mouse with the left button held down until it lines up properly with the drainage system. Then release the button.
| Zooming the Map |
To Zoom In on the Study Area Map:
| 1. | Select View >> Zoom In from the Main Menu or click the |
| 2. | To zoom in 100% (i.e., 2X), move the mouse to the center of the zoom area and click the left button. |
| 3. | To perform a custom zoom, move the mouse to the upper left corner of the zoom area and with the left button pressed down, draw a rectangular outline around the zoom area. Then release the left button. |
To Zoom Out on the Study Area Map:
| 1. | Select View >> Zoom Out from the Main Menu or click |
| 2. | The map will be returned to the view in effect at the previous zoom level. |
| Viewing Results on the Map |
There are several ways to view the values of certain input parameters and simulation results directly on the Study Area Map:
| · | For the current settings on the Map Browser, the subcatchments, nodes and links of the map will be colored according to their respective Map Legends. The map's color coding will be updated as a new time period is selected in the Map Browser. |
| · | When the Flyover Map Labeling program preference is selected, moving the mouse over any map object will display its ID name and the value of its current theme parameter in a hint-style box. |
| · | ID names and parameter values can be displayed next to all subcatchments, nodes and/or links by selecting the appropriate options on the Annotation page of the Map Options dialog. |
| · | Subcatchments, nodes or links meeting a specific criterion can be identified by submitting a Map Query. |
| · | You can animate the display of results on the network map either forward or backward in time by using the controls on the Animator panel of the Map Browser. |
| · | The map can be printed, copied to the Windows clipboard, or saved as a DXF file or Windows metafile. |
| Viewing at Full Extent |
To view the Study Area Map at full extent, either:
| a) | select View >> Full Extent from the Main Menu, or |
| b) | click the button. |
| Utilizing a Backdrop Image |
SWMM can display a Backdrop Image behind the Study Area Map. The backdrop image might be a street map, utility map, topographic map, site development plan, or any other relevant picture or drawing. For example, using a street map would simplify the process of adding sewer lines to the project since one could essentially digitize the drainage system's nodes and links directly on top of it.
The Backdrop Image must be a Windows metafile, bitmap, or JPEG image created outside of SWMM. Once imported, its features cannot be edited, although its scale and viewing area will change as the map window is zoomed and panned. For this reason metafiles work better than bitmaps or JPEGs since they will not loose resolution when re-scaled. Most CAD and GIS programs have the ability to save their drawings and maps as metafiles.
Selecting View >> Backdrop from the Main Menu will display a sub-menu with the following commands:
Load (loads a backdrop image file into the project)
Unload (unloads the backdrop image from the project)
Align (aligns the drainage system schematic with the backdrop)
Resize(resizes the map dimensions of the backdrop)
Watermark (toggles the backdrop image appearance between normal and lightened)
The name of the backdrop file and its map dimensions are saved along with the rest of a project's data whenever the project is saved to file.
For best results in using a backdrop image:
| · | Use a metafile, not a bitmap. |
| · | Dimension the Study Area Map so that its bounding rectangle has the same aspect ratio (width-to-height ratio) as the backdrop. |
| Panning the Map |
To pan across the Study Area Map window:
| 1. | Select View >> Pan from the Main Menu or click the |
| 2. | With the left button held down over any point on the map, drag the mouse in the direction you wish to pan in. |
| 3. | Release the mouse button to complete the pan. |
To pan using the Overview Map:
| 1. | If not already visible, bring up the Overview Map by selecting View >> Overview Map from the Main Menu or click the |
| 2. | If the Study Area Map has been zoomed in, an outline of the current viewing area will appear on the Overview Map. Position the mouse within this outline on the Overview Map. |
| 3. | With the left button held down, drag the outline to a new position. |
| 4. | Release the mouse button and the Study Area Map will be panned to an area corresponding to the outline on the Overview Map. |
| Selecting a Map Theme |
A map theme displays object properties in color-coded fashion on the Study Area Map. The dropdown list boxes on the Map Browser are used for selecting a theme to display for Subcatchments, Nodes and Links.
Methods for changing the color-coding associated with a theme are discussed in Using the Map Legends.
| Aligning a Backdrop Image |
To align a backdrop image with the drainage system schematic on the Study Area Map:
| 1. | Select View >> Backdrop >> Align from the Main Menu. |
| 2. | Move the backdrop image across the Study Area Map by moving the mouse with the left button held down until it lines up properly with the drainage system. Then release the button. |
Methods for changing the color-coding associated with a theme are discussed in Using the Map Legends.
| Legend Editor |
The Legend Editor (pictured below) is used to set numerical ranges to which different colors are assigned for viewing a particular parameter on the Study Area Map.
| · | Numerical values, in increasing order, are entered in the edit boxes to define the ranges. Not all four boxes need to have values. |
| · | To change a color, click on its color band in the Editor and then select a new color from the Color Dialog box that will appear. |
| · | Click the Auto-Scale button to automatically assign ranges based on the minimum and maximum values attained by the parameter in question at the current time period. |
| · | The Color Ramp button is used to select from a list of built-in color schemes. |
| · | The Reverse Colors button reverses the ordering of the current set of colors (the color in the lowest range becomes that of the highest range and so on). |
| · | Check Framed if you want a frame drawn around the legend. |
Changes made to a legend are saved with the project's settings and remain in effect when the project is re-opened in a subsequent session.
| Using the Map Legends |
| Map Legends associate a color with a range of values for the current theme being viewed. Separate legends exist for Subcatchments, Nodes, and Links. A Date/Time Legend is also available for displaying the date and clock time of the simulation period being viewed on the map. |  |
To display or hide a map legend:
| 1. | Select View >> Legends from the Main Menu or right click on the map and select Legends from the pop-up menu that appears. |
| 2. | Click on the type of legend whose display should be toggled on or off. |
A visible legend can also be hidden by double clicking on it.
To move a legend to another location press the left mouse button over the legend, drag the legend to its new location with the button held down, and then release the button.
To edit a legend, either select View >> Legends >> Modify from the Main Menu or right click on the legend if it is visible. Then use the Legend Editor dialog that appears to modify the legend's colors and intervals.
| Using the Overview Map |
The Overview Map, as pictured below, allows one to see where in terms of the overall system the main Study Area Map is currently focused. The current zoom area is depicted by the rectangular outline displayed on the Overview Map. As you drag this rectangle to another position the view within the main map will be redrawn accordingly. The Overview Map can be toggled on and off by selecting View >> Overview Map from the Main Menu or by clicking the button. The Overview Map window can also be dragged to any position as well as be re-sized.
| Copy Dialog |
The Copy dialog appears when the Edit >> Copy To command is selected. Use the Copy dialog as follows to define how you want your data copied and to where:
| 1. | Select a destination for the material being copied (Clipboard or File) |
| 2. | Select a format to copy in: |
| · | Bitmap (graphics only) |
| · | Metafile (graphics only) |
| · | Data (text, selected cells in a table, or data used to construct a graph) |
| 3. | Click OK to accept your selections or Cancel to cancel the copy request. |
The bitmap format copies the individual pixels of a graphic. The metafile format copies the instructions used to create the graphic and is more suitable for pasting into word processing documents where the graphic can be re-scaled without loosing resolution. When data is copied, it can be pasted directly into a spreadsheet program to create customized tables or charts.