Preparing a Base Map of Reno from TIGER/Line Files

We'd like to create a base map of Reno streets that contain Zip Code and Zip+4 add on postal codes from TIGER/Line 1997 files.  We use the TIGER/Line '97 files in this example because they are the most recent; however, the procedure is the same for TIGER/Line 1995.  We are going to use this map in a proximity analysis to find all the Zip codes within a certain distance of Frank's Catering locations.   Click on the thumbnails to get bigger images.

This example proceeds the way an experienced user would do this task.  It includes some steps that are not strictly necessary, but which make the job visually more elegant or faster.  If you are not already a Manifold user, do not be put off by the step-by-step nature of this presentation.  The steps below are usually each accomplished with one or two mouse clicks and thus proceed far faster and easier than reading about them on a web site!

Part I: Finding the Right TIGER/Line Files

TIGER/Line files are published as zip files, one zip file per county.  The zip file unzips into a dozen or more files that contain all the different information sets found in TIGER/Line for that particular county.   The zip files are named by the State and County FIPS (Federal Information Processing Standard) number codes.  Let's say we know that Reno is located in Washoe County, Nevada, because that's how we've been paying our property tax bills all these years.  Our first obstacle is to find the FIPS code for Washoe county.  We can use Manifold to do this. We are going to create a map of county centroids with the county name and the FIPS code printed as a label for each centroid, as in the illustration at left.

1. Load the Nevada and County maps from the CD - From the Manifold CD, load the dlg2mi\Nv.mfd map, a 1:2,000,000-scale map from the USGS.  This is a handy base map. By double-clicking on the layer tabs, turn off all layers other than Roads, so the map is not too "busy".  Now, load the misc\county_centroids.mfd map, a map of county centroids.

2. Turn on Field Labels for FIPS code and County Name - Click on the county_centroids map layer tab to make sure it is active (ie, white).  Click on the Format Fields toolbar button to call up the field formatting display. First, we will turn on labels for the FIPS codes. 

2a.  A refinement: Format only some field labels to save time -  There are thousands of counties in the US.  By simply formatting all the FIPS and name labels "ON", you might   wait a few dozen seconds on a slow machine.  An expert user would only format those labels on that he or she requires.  This is done by first selecting those points visible on screen in the area of interest, and then pushing in the Format Selection button so that the subsequent Format Fields operation applies only to the selected points.    Select the points by using Open Box or Closed Box select (ie, draw a box around the desired points with the mouse cursor). Make sure the Select Lines mode button is OFF as in the illustration above and left, so that lines are not also selected.   Click in the Format Selection button (the format palette with a splash of red in the illustration at right) and then go ahead and click the Format Fields button as shown in step 2 above.

Not only is this method fast, it is extraordinarily flexible.  You can select individual points, and if the Format Selection button is pushed in, apply the subsequent formatting to that one point only.  One can therefore format any object or any combination of objects in a separate way.

3. Turn on the FIPS Codes - The thumbnail expands into a view of the label/field formatting dialog.  Highlight the data attribute field that you wish to display as a label, specify the colors, fonts, point sizes, whether or not you want a pretty box, the alignment of the label relative to the object, etc, and then click Show.  We've used black color, MS San Serif font in 10 pts, an alignment to the upper right of the object with the alignment slider (sets how far from the object the label appears) nudging the label out a bit from the center.

4. Turn on the County Names - After we hit Show for the FIPS codes, we then highlighted the county names and set the parameters we desired to be used to display county names labels.  We then hit Show again.   For county names we used Courier New in 8pt size using a blueish dark green color.   Alignment is to the lower left from the object.  Note: It's no big deal for such a simple "take a look at the data" map, but if we don't like how Manifold aligns the labels for us, we can simply drag them and drop them as we like using the mouse.

Results! - Washoe county is FIPS code 31.  Could we have looked up this FIPS code in a government publication?  Sure.  However, there is a lot of data on the Manifold CD and even more in the Manifold web site.  If you have Manifold you can browse this data much faster than finding a publication and looking it up. Another benefit is that the visual display of FIPS data usually makes it much harder to make a mistake compared to pulling numbers out of text lists.  However, using the map is not always clear.  Washoe County, for example, is a North-South oriented county without much extent in the East-West direction, so the centroid of the county does not fall right on top of Reno.Suppose we weren't quite sure what county Reno was in?   We could simply turn on the Boundaries layer and see for sure, or perhaps even load the place_centroids database that includes county and state FIPS codes for various places.   

Part II: Creating a Custom Map from TIGER/Line Files

1. Copy and Unzip TIGER/Line Files - If your CD drive is D: and has the TIGER/Line CD with Nevada loaded into it, the desired file is D:\TIGER\32_NV\Tgr32031.zip.   (By inspection, you can see that TIGER believes the State FIPS code for Nevada is 32) copy this file to your working directory (we'll call ours "Washoe") and unzip it.  Over a dozen files will unzip out of the zip archive.  These various files contain the TIGER/Line data for Washoe County.

2. Launch Manifold and Import TIGER/Line Files - Launch Manifold and choose File - New, and launch the new map wizard at the location of the Washoe county files you just unzipped.  The MFD and MDB names are how you wish to name the new map you are going to create.  We'll call ours Reno_tiger.   See the thumbnail at left for greater detail.

3. Specify Which TIGER/Line Data to Import - As you can see from expanding the thumbnail at left, which shows only a small part of the available TIGER/Line data attributes, TIGER/Line contains a huge amount of data.   Manifold provides a list of data attributes available for import.  Check the boxes of those fields you want imported. We will keep things simple and check only the boxes for +4 postal Add-on Code left and right, Feature Name and Feature Type, and Zip Code left and right. Click Finish and Manifold will go out and import the TIGER/Line map.

4.   Zoom into Reno Area -  TIGER/Line has so much information, that the map initially imported is not particularly pleasant to look at or work with (illustration at right).  We are going to zoom into the dark blotch at the lower left of the map, which is obviously Reno,  and then clean up the display.  Even zoomed in (thumbnail) the map is still too "busy" for our tastes.

5. Clean Up Map -  This is an optional step, but one which takes only a second or two and which makes the map a lot more pleasant to look at.

5a. Turn off Areas and Points - We first set up selection modes to select only Areas and Points, and then we use Open Box selection (the mouse selects all objects any part of which is inside the selection box) to Select all the Areas and Points in the Map.  Then, we Save the Selection to a New Layer, called "temp" and we turn that layer off from display by double clicking on it.  Even a Manifold newbie can do that faster than it takes to read this paragraph.  The first thumbnail at right shows the areas and points highlighted in Red after they are selected, and the second thumbnail shows how the map looks after they've been sent to the temp layer and that layer turned OFF.  Notice how the light brown background color shows through the entire map after the black-and-white hatched pattern areas have been removed from the display.

6. Select Lines in Target Area - We now change the selection mode button so that only Lines are selected (illustration at left) and we will use Open Box Select to select all the lines in a rectangular area that we wish to comprise our custom map.  Of course, we could also use Circle Select or Polygon (ie, freehand lasso) Select if we wanted to grab lines in a different way than simply all those that fit inside a particular rectangle.  The thumbnail at right shows the lines we've selected highlighted in Red.

7. Show the Selection in Table View - Our custom map will be used to find Zip+4 codes associated with streets in the Reno area.  We don't care about lines showing water features, or even street segments that for some reason or another don't have zip code attached.  So, for this map we will only use lines that have Zip codes attached.  We will use Table View to further select the data we want.  We begin by clicking on the Show Selection as Table button, which displays all the selected objects in Table View.

8. Use Table View to Pick Out Only those Lines We Want - Click on both of the Zip Code columns to sort the Table by Zip Code.  This effectively puts all the objects that contain a Zip code at the top of the table.   Click on the topmost record to highlight it, and then scroll down through the table until you come to the last record that contains a Zip code.  Shift-Click on that record, and all the records from the first record to this one will be highlighted.   (thumbnail at left.)

9. Save the Highlighted Records to a New Map - Push the Actions button to call up a list of actions, and choose Save as Map. This will write out all the highlighted records to a new map.  In the dialog prompting for a name for the new map, use Reno_tiger_o.  We're going to convert that map into an Orthogonal projected map, so may as well name it right away with some name that indicates it is a projected map.  We use a system of appending an _o to indicate all our maps that are projected using the Orthogonal projection. Use whatever naming convention you find convenient.

After the Save as Map command runs to completion, you've already created the new map. It's been saved with all the data attributes in Table View, but only those records highlighted are in the new map.  The next step is to exit the map with which we've been working, and then load the Reno_tiger_o map and change it to some projection from straight Lat/Lon.

Note that in this case study, we're only interested in lines that contain Zip+4 information and have discarded all other information in the creation of our custom map.  For other maps or other purposes, of course, we could use similar techniques to achieve whatever combination of data is desired.  One can use Selection, Solvers, the creation of new objects, the Morph tools, the facilities of Table View calculator and many other tools to extract the data desired.  At the end, simply highlight what objects are desired (it might even be a "highlight all") and write them out from Table View to a new map.

10. Convert the New Map to Projected Form - We will be doing distance measurements, so we want our new map in projected form to be able to utilize all the various distance measurement features within Manifold.  So, we will load Reno_tiger_o and convert it to some projection.  In this example, we will use the Orthographic projection.   Begin by loading the Reno_tiger_o using File - New and specify use of an existing map in the New Map Wizard.  Choose the Tools - Projections menu item.

11. Specify Orthographic Projection and Convert - In the Target projection dialog, choose Orthographic from the pull-down menu of projections.  Enter 37 for the latitude origin  and -120 for the longitude origin.  See the thumbnail at left for an example. You can pick whatever values you like that are reasonably near Reno.  We've used these two values because we are also creating projected, custom maps for California (the RV SuperStores case study) today and we have found it convenient to project all the maps using the same parameters.  Why Orthographic? ... Why not?   We go through phases where we use one projection more than another.  If the entire US were involved, a better choice would be one of the Lambert projections that allow setting of standard parallels.  See the Manifold Help file for an extensive discussion on choosing projections.

12. Save Workspace and Declare Victory - Save the workspace (use any name you like) so that the map is saved as a projected map.  That's it!

Note that the map prepared is missing some street segments where TIGER/Line did not code Zip codes for the segment.  We left those behind when we created this map because we were only interested in segments that had zip codes.

Note that the Reno map used in the Frank's Catering case study has had all the street segments brought along, even those that don't have zip codes. 

We've used only a small fraction of Manifold's capabilities to extract this data from TIGER/Line and to create a new, custom map containing just that subset of data we want.   Using the same methods while employing a greater repretoire of commands can create whatever custom map we need.  Keep in mind that it is also quite simple to use the Merge Data engine to bring data into a map from another map.  So, one can bring data into maps or extract data from maps to achieve any combination of data desired.

Likewise, in this example we've extracted data of interest that is associated with line segments.  Perhaps in different applications we are interested in data associated with areas.  We could use SQL toolbar or expert SQL or solvers to grab data/objects as desired and save them as new, custom maps.

Like what you see? Now is the time to buy Manifold System and get all these capabilities for yourself.  It's only $145 and it totally outperforms ancient systems from an earlier era.  You get more power, better ease of use and a spectacularly driven engineering organization working to serve you better.  While you are at it, why not order a copy of TIGER/Line 1997 as well? TIGER/Line 1997 data set is only $97 from manifold.net, a savings of $1403 compared to the Census Bureau's rip-off price of $1500 for exactly the same data set. Visit the Manifold.net Online Store for a quick, easy, and secure purchase of Manifold products, or (in the US) call 800-556-5919 to order by telephone (9-5 PST).

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