Creating a New Shapefile in ArcGIS: Part I

I’m working with a grad student who needs to create a new shapefile from scratch, and thought I’d turn the instructions for doing this in ArcGIS into a tutorial / post for creating new point layers. The idea in this example is to create a point layer that shows the relative center of 291 neighborhoods in New York City. Since many of these neighborhoods are place names without finite boundaries, we’ll have to use various sources (NYC Planning map and Rand McNally street maps) to pinpoint the relative center of each neighborhood.

These points will be used for labeling each neighborhood. In this case, creating a new, georeferenced layer is preferable to creating 291 text labels on a map that are not tied to geography in any way.

  • The first step is to download some layers from the NYC Department of Planning to use for reference, such as a layer for boroughs and community districts. Community districts are used by the city to approximate neighborhoods. Many of the neighborhoods that we are trying to plot are, in many cases, smaller areas or places within these boundaries.
  • scrnshot1Next, open ArcCatalog and create a folder to store the data. Then, right click on the folder in the table of contents and select New – Shapefile. In the Create New Shapefile window, we give the shapefile a name, select Point as the feature type, and hit Edit to change the
    coordinate system. In the Spatial Reference Properties menu, we’ll import a coordinate system from one of the files we downloaded from NYC Planning, which uses New York State Plane for Long Island. Click OK and OK again, and we’ll have a new shapefile.
  • scrnshot2Right now, our new shapefile isn’t very exciting because it’s empty – you can preview it in the catalog to see for yourself. If you preview the table, you’ll see that Arc created three fields – FID, Shape, and ID, which it will automatically fill in when we start creating features. Before we do that, we’ll have to add an additional column to store the name of the neighborhood. To do that, open ArcMap and add the neighborhood layer to the map. Then, right click on the layer in the Table of Contents and open the attribute table. Hit the Options button and choose Add Field. In the Add Field menu, name the new field, choose Text as the type, and change the length to 80 (in case we have some neighborhoods with long names). Hit OK, and you’ll have a new field.
  • scrnshot3Let’s add our reference layers next. Hit the Add Data button (or File – Add Data), and add the borough boundaries and community districts (if you don’t see anything after you add them, right click on one of these layers and choose Zoom to Layer). Go into the symbology tab for each layer and change their display to make the areas appear more distinctive. Make sure your neighborhood layer is on top of your other layers.
  • Now it’s time to start plotting neighborhoods. Go to the Selection menu – Set selectable Layers, and turn off all the layers except the neighborhood layer. Then, use the dropdown on the Editor Toolbar and Select Start Editing (if you don’t see the Editor Toolbar, make sure it’s activated by going to View – Toolbars and select it). scrnshot4On the Editor Toolbar, make sure the Create New Feature task is activated and that the target layer is the neighborhood layer, and not any of the reference layers. Zoom in to the top of Manhattan. With the Pencil tool selected in the toolbar, and using your sources (NYC planning map, Rand McNally street map, whatever), click on the map to approximate where the center of the Inwood neighborhood would be. A blue dot should appear on the map. Then right-click on the neighborhoods layer in the Table of Contents and open the attributes table. You’ll see a brand new record for your new dot. Click in the empty field for Name, type in the name of the neighborhood, and press enter.
  • That’s the process! Next, locate the area for Washington Heights and click on the map to create the point for that neighborhood. The new dot will appear hi-lighted, while the previous dot for Inwood will now appear as a regular point symbol. Now it’s just a matter of plugging away. Make sure to occasionally save your edits by clicking Editor and choosing Save Edits. If you make a mistake, you can delete a feature by selecting the Select Feature tool in the regular tool bar (white arrow with a blue and white feature box next to it), select the particular point, and hit the delete key. If you’re having trouble pinpointing the right location for the neighborhood, try downloading additional reference layers to guide you. The NYC DOITT also has a page with GIS layers for the city with features like parks and streets that may be helpful. When you’re finished editing, choose Stop Editing under the Editor Toolbar.

    scrnshot5

  • The ultimate goal of this exercise was to get neighborhood labels to appear without the actual point. To accomplish this, change the point symbol for the neighborhood to nothing by going into the Symbology tab for the layer and reducing the fill to no color, the outline to nothing, and the size to zero. Then open the Labels tab under the Properties menu, turn labels on using the name field as the label field, select Placement Properties and choose the setting to place the labels on top of the point, hit ok, and voila! Perfectly centered neighborhood names that are part of a georeferenced layer.

This covers the basics. In the next post, I’ll go a little further and discuss adding additional fields to the new file, without having to type them in manually.

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