GIS for Civil Engineering
Site optimization: Locate suitable sites for a new wastewater treatment plan.
Criteria:
Must be within 3,000 feet of the Cache la Poudre River
Must be within 1 mile of the city limits
Must be at least 300 feet from residential parcels and parks
Must lie outside the flood plain
Must be on vacant parcels that are 50,000 square feet or greater
Getting Familiar with your Data: ArcCatalog
Open ArcCatalog.
Expand the folder connection to the BldgModels10_0 folder. Notice that there are several feature classes and raster datasets in this geodatabase.
Expand FtCollins.gdb to view its contents.
From criteria to analysis:
Must be within 3,000 feet of the Cache la Poudre River - Buffer tool
Must be within 1 mile of the city limits - Buffer tool
Must be at least 300 feet from residential parcels and parks - Buffer tool
Must lie outside the flood plain - Erase tool
Must be on vacant parcels that are 50,000 square feet or greater - query -> Select tool
Running your Analysis: ArcMap
Open the SitePlant.mxd document.
Set the default geodatabase to FtCollins.gdb by right-clicking in the Catalog window and choose Make Default Geodatabase.
Select a feature using a query
Our first criteria focus in just one of the records in the Hydro layer. We want to buffer only the select the Cache la Poudre River as the main water feature for your analysis. Because all geoprocessing tools honor selected sets, you can simply make a selection rather than creating new data containing only the river. This operation will help you fulfill the criterion of close proximity to the river.
Press the Ctrl key and then uncheck any layer name to turn off all layers.
Turn on the Hydro layer only.
From the Selection menu, choose Select By Attributes.
Change the Layer to Hydro.
Build the following expression: NAME = 'Cache La Poudre River'. (ArcGIS 10.0 or 10.1 users: Build this expression:"NAME" = 'Cache La Poudre River'.)
Click OK to make the selection.
Now the Cache la Poudre River is selected in the map.
Hold down Ctrl on your keyboard while you click an unchecked layer's checkbox to turn on all the layers again.
Save your map.
Create buffers
On the Standard toolbar in ArcMap, click the Search Window button .
In the Search window, click Tools to include only tools in your search results.
Type buffer and click the Search button
.
Open the buffer tool.
Buffering the river
Double-click the Buffer tool to open its dialog box, and then set the following parameters.
Input Features: Hydro
Output Feature Class: RiverBuf
Distance > Linear unit: 3000 Feet
Buffering the city limits
Open the dialog box for the second Buffer tool and set the following parameters:
Input Features: City Limits
Output Feature Class: CityBuf
Distance > Linear unit: 1 Miles
Buffering residential areas
Input Features: Residential Parcels
Output Feature Class: ResBuf
Distance > Linear unit: 300 Feet
Buffering parks
Open the dialog box for the other new Buffer tool and set the following parameters:
Input Features: Parks
Output Feature Class: ParksBuf
Distance > Linear unit: 300 Feet
Locate common areas of two buffers
Next, you want to locate the common areas between the two buffers (in other words, the suitable areas). This can be done in two ways: using the Clip tool or performing the Intersect overlay operation.
The Intersect overlay operation allows you to combine the attributes of these buffers. However, you do not need to do this, so you will use the Clip tool to extrapolate the common areas.
In the Search window, type Clip to find the Clip (Analysis) tool and add it to the model under RiverBuf and CityBuf.Open the dialog box for Clip and set the following parameters:Input Features: CityBuf
Clip Features: RiverBuf
Output Feature Class: MustBeIn
Locate initial unsuitable areas
The goal of this step is to combine all unsuitable areas into a single feature class. You can do this in one of several ways.
Search for and open the Union tool.
Open the dialog box for the Union tool and set the following parameters:
Input Datasets: ResBuf, ParksBuf, Flood Plain (Hint: Because Flood Plain on its own is unsuitable, no buffer is necessary.)
Target Dataset: Unsuitable
Automating the process: Model builder
Creating a new toolbox and model
Right-click FtCollins.gdb and choose New > Toolbox. Name the new toolbox Site_Plant.
Right-click the new toolbox and choose New > Model.
A blank new model opens.
From the Model menu, choose Model Properties.
On the General tab, set the following properties:
Name: WastewaterSiteSel
Label: Wastewater Site Sel
Check the box to store relative pathnames.
Click Apply.
Select the Environments tab.
Scroll down to Workspace, expand it, and the check the Current Workspace box. Click Values and expand Workspace.
Click OK on all dialog boxes.
From the Model menu, choose Diagram Properties.
Click the Layout tab and choose Top to Bottom.
Click OK, save the model, and minimize it.
