Preprocessing: Clipping Layers to Brooklyn

To begin, we want to make sure that all of the datasets we will be using are clipped to the shoreline of Brooklyn. This will prevent any mistakes when adding data to the geodatabase, as well as lighten the computation required to perform some of the analysis.

Limiting to Brooklyn Borough Boundary:
To quickly limit your project to the Brooklyn Borough Boundary, add the dataset and select the Select Features tool from your menubar. Once selected, click on Brooklyn and an outline should appear around the borough. Now, simply right-click on the layer and navigate to Data > Export Data and export a shapefile to a folder within your active directory.

Clipping MTA Subway Stations:
To clip the MTA Subway Stations to the Brooklyn Boundary, import your MTA dataset and navigate to Geoprocessing > Clip in your menu bar. Set the Input Features to MTA Subway Stations and Clip Features to the shapefile you just created (Brooklyn Borough Boundary) and select save.

Preprocessing: Creating GeoDatabase

Unfold your Catalog menu bar on the right hand side of your window and on the top select the Connect to Folder icon. Navigate to your working drive and select ok. We will give our DB the name BKLibraryAnalysis.gdb. Next, within your geodatabase, we will create a new Feature Dataset. To do so, right click on your newly generated geodatabase and select New > Feature Dataset. Give it a similar name and save it to your directory.

Preprocessing: Selecting from LION

Within the LION Dataset, we only want to use roads that are found within Brooklyn and have pedestrian walkways. To do so, enter the following filter within the Selection > Select by Attributes menu. In the query builder, enter FeatureTyp <> 'F' AND RBoro = 3 AND TrafDir <> '0' AND NonPed <> 'V'. A detailed writeup on each of these fields can be found in the metadata (link above). Once you have your items selected, navigate to Data > Export Data and export a File and Personal Geodatabase feature classes file into the newly generated Feature Dataset. Make sure that you navigate into this directory, as opposed to the geodatabase directory.

Preprocessing: Creating Feature Dataset

Now, you should import your remaining features (libraries, subway stations, and the borough boundary) to the Feature Dataset by navigating to Import > Feature Class (Multiple). Select each of your layers and select OK. Now remove all old layers.

Preprocessing: Creating Network Dataset

Now we will prepare a network dataset. Right click on your Feature Dataset and navigate to New > Create Network Dataset and follow the steps below:

• On the landing page, the default name (BKLibraryAnalysis_ND) is fine. Select the most up-to-date version. In our instance, this is 10.1

• On the second page, select only the BKLION dataset.

• On the third page, indicate that you would like to turn this into a network dataset (selected by default).

• Under connectivity, leave the settings as is.

• On the fifth page, you'll be asked about how you'd like to model the elevation of your dataset. Select None.

• On the sixth page, you'll be asked about attributes of your network. Since we are building a network from the LION dataset, we will be provided with two rows: Length & Road Class. Remove Road Class, as we won't be using this for our network build.

• On the seventh page, we will bypass these settings, as we won't be assigning a travel mode (measuring by length).

• On the eight page, we will be asked to establish driving directions. Again, this is not the purpose of our network, so we will select No.

• We will then be asked if we want to build a Service Area Index. Check the box.

• Select Finish and ArcMap will begin building the network. Once created, it will prompt you if you'd like to Build the network. Select Yes. You'll again be prompted to whether or not you'd like to add all feature classes to the map. Select Yes.

You've now generated your first network dataset.