Geocoding - get street segment

BarbaraTreude

Hello to everybody,

I am quite new to ArcGIS and could really need some support.

I am using the US Census' TIGER files' data to geocode addresses for an academic research. In addition to latitude and longitude of the actual address, I also need to know the street side the house is on and the corresponding street segment. For your information: In the TIGER files, the left and right side of a street are determined by "walking" from the start to the end node. Start and end node, however, do not necessarily correspond with the beginning and end of the respective street segment.

At best, in addition to the street side that the geocoding process provides me with, I will get the start and end node's coordinates. Is there any way to do that? Using the standard geocoding tool, I don't see how to do that, unfortunately. Do you have any ideas?

As a workaround, since the TIGER files use interpolation, I have geocoded the addresses next to the house, i.e. house number + 2. That will leave me with a very rough estimation of the coordinates of the street segment's node. That is OK, however, since I am really only interested in the bearing of the street. Nevertheless, it is not specific on the street side. So, also as a workaround, is it possible to get information on which node corresponds with what end of the address range, that is to say, is the start node also the beginning of the address range or the other way round?

Many thanks to all of you in advance! If there are still any uncertanties about what I actually want ArcGIS to do, please feel free to ask.

Cheers,
Barbara

JoeBorgione

Let's see if I can sort this out...

When geocoding against street data, the geocoder "looks" for a corresponding street name with a range of addresses that will encompass the specific house number to be located.  Typically, address ranges are assgined with respect to the 'FROM' and 'TO' nodes of a given segment; in other words, the smaller numbers are From while the larger numbers are To. So if we were to geocode an address of 101 S Main St, the locator looks for a segement with the components of S = PreDir, Main = Name and ST = Type.  Then it looks for a segment with a range that 101 falls within.  Lets' say it finds a segment that has 100-198 on the even side and 101-199 on the odd side for ranges.  It then interploates a location based on the the length of the street segement, the range, and the given address.  We would expect to see 101 S Main St located very close to the 'FROM' node. 

Whenever you use linear features like streets for geocoding, the location will be interpolated; this is not unique to Tiger files.

Consider the same street but a different address: 150 S Main St.  The locator will place the point right in the middle of the block on the even side of the street.  The reality might be that house number 150 is actually located as the last house on the block and on odd side of the street.  Geocoding against lines is accurate, but not truly precise.

Again, typically, any addressing system is based on some sort of grid with a point of origin; that's not always an easily discovered fact and it's not alwyas easy to find the point of origin.  For use in geocoding the streets should be oriented from the origin; from/to nodes should be all lined up segment to segment when 'traveling' in the same direction.  In a perfect world, even numbers are on one side of the street, while odd numbers are on the other.

Results obtained from geocoding are only as good as the data you match against.

With respect to your question about getting location values of From/To nodes; yes, you can easily tease that information out of a street.  You will need to add 4 attributes all as 'double' type.  Name them something like FromXCoord, FromYcoord, ToXCoord, ToYCoord.  Using the the Calculate Geometry tool, you can populate these fields accordingly.

Hope this helps-