Los Angeles County GIS Data Portal » Internal Services Department

Airport Runways

Mark Greninger — Tue, 29 Jan 2013 21:38:44 +0000

Airport Runways in the County of Los Angeles digitized from high-resolution aerial photography.

The runways include all paved and access tarmacs to the flight lines.

Download

lacounty_airport_runways (zipped shapefile).

LA County Specific Locators and Matching Rules

Mark Greninger — Sat, 10 Dec 2011 01:43:17 +0000

Note – this is NOT a data download, it is a highly post, with downloads enabling GIS professionals with ESRI’s ArcGIS Software to embed enhanced geocoding rules into ESRI software for improving matching rates.

LA County currently is able to match over 99.5% of incoming addresses. Part of this has to do with the high quality of the reference file that we manage through the Countywide Address Management System, but a large part of this success rate has to do with something that many people take for granted – the geocode matching algorithms.

Background

Some of this is my memory from conversations with Peter Fonda-Bonardi so I will follow up with him to validate. I spoke about our programs and history a little while ago at the 1st International Geocoding Conference: I’ve attached the presentation materials here: Using GIS to improve Addressing (.pdf file)

In the mid-1980′s, LA County hired Matt Jaro to design and build a fuzzy matching system to automate the matching of misspelled names (MediCal and MediCare patients that hand’t registered correctly and therefore the County wasn’t able to get reimbursement for health services rendered). This has led to the recovery of millions of dollars in revenue for the County based upon their standalone version of the software running on a UNIX platform.

The outcome of this was a matching program called Automatch developed by MatchWare technologies (here’s an article written by Matt Jaro). This software was then licensed by ESRI to improve its matching at the time. Yes – LA County’s matcher is inside of ArcMap (but is being phased out starting with ArcGIS 10).

The team responsible for developing the tool, led by Wayne Bannister, Peter Fonda-Bonardi, Victor Chen, and Yoko Myers of LA County’s Internal Services Department Urban Research Section, are intimately familiar with the complex mathematics and pattern rules that make up the matching systems, and have tweaked them to be especially accurate in dealing with the strange addresses in LA County. Some examples include (these all exist!):

W Avenue Q
Avenue 23
The Old Road
Outer Traffic Circle
Los Coyotes Diagonal
Avenue of the Stars

Why? Peter Fonda-Bonardi optimized the way street names are broken apart so that they could be recognized more effectively, so that strange names don’t “break” the rules for addresses. His expertise and understanding of the County’s 30+ addressing and house number systems (yes there are that many) have played a major role in getting us to where we are today.

Where we are now

A couple of years ago we were able to work with ESRI to bring the pattern rules back into their software, which has improved the County’s ability to geocode difficult street names, and provide these both as geocoding files and services underpinning many of our applications. So now we can leverage all of the expertise and work that Peter and Victor have put into the matcher within the general systems we use.

Download the Matching rules

All required files are in this zip file: LACounty_Locators.zip

How to use these matchers

NOTE: this is very technical, and I assume ability to unzip files, know where your ArcGIS is installed. NOT for the faint of heart!

New Locators

Step 1: Unzip the files to the correct folders Make sure to back up your current folders first

The zip file has two folders in it that match two folders in your ArcGIS installation location. Unzip folders, then copy the files in the zip file to the same folders in your ArcGIS Desktop Installation, in my case this was C:\Program Files\ArcGIS\Desktop10.0

All files in the Geocode folder –> C:\Program Files\ArcGIS\Desktop10.0\Geocode
All files in the Locators folder –> C:\Program Files\ArcGIS\Desktop10.0\Locators

From this point forward you will find three new locators in your “Address Locator Style” list (see picture at right).

Step 2: Standardize your reference file

You need to format your reference file (standardize it) using the same rules that you will use to match. This is critical for success – otherwise the address matcher doesn’t know what to match!

The “Standardize Addresses” Tool is available under the “Geocoding Tools” in Arc Toolbox. Open that tool.

Using the standardizer

There are five boxes:

Input Address data – this is your reference data file (could be TIGER, etc)
Input Address Fields. You need to fill this out correctly.

Add the FID or OBJECTID field – ArcMap needs a unique identifier.
Add ALL of the fields that make up the address. Sometimes this is one field (TIGER’s FULLNAME), but if you have multiple fields (PRETYPE, PREDIR, etc) you will need to add them all, and in the correct order. The standardizer will concatenate them before splitting them according to LA Countys’ rules. DO NOT include address number, zipcode, or city fields.

Address Locator Style – By completing Step 1, you should see three new locators starting with “LA County” in this list. You need to know the type of your data to select the correct one:

LA County Points with Zone – this is for address points
LA County Streets with Zone DIME - this is the most common format (TIGER is one – it invented this format). If you have left and right house ranges (Look for 4 columns with address numbers in them).
LA County Streets with Zone NICKEL – very uncommon (but LA County uses it) – each record is a single range (left or right side) – look for only 2 columns with address numbers)

Output Address Fields – CLick on “Select All” then uncheck the HouseNum, HouseSuffix, and ZIP fields. Generally these already exist as separate fields in your dataset – no need to output them again.
Output Address Data – select where you want the file to be output.

Click “OK” - you will see this process run, and a new file will be output, which includes a set of new fields optimized for the LA County locator.

Step 3: Create your address locator

Creating the Address Locator

From the ArcToolbox “Geocoding Tools” you can get the “Create Address Locator”

There are five boxes:

Address Locator Style – same as #3 in the last step – it has to match the reference dataset
Reference Data – select the output from the standardizer.
Field Map When you selected the Reference Data, all of the fields should be filled in.

You may see a blank next to the “*House Number” or “House From Left” field name – you need to select the field or fields that contain that data in your reference file.
You need to go to the bottom of the list and check the Zone fields – Make sure they are filled in with the correct Zone information (this could be zipcode but could also be a city).
We generally create one locator for zipcode, one locator for legal city, and one locator for postal city (if your reference data has these fields) – then tie them together with a Composite Locator (which I won’t discuss here).

Output address locator – this is the name and location of the address locator that you will use for geocoding. Make sure that it shows the zone information (e.g. Points_Zip vs. Points_LegalCity) so you know what it contains.

Click OK - the address locator will be created. Have fun geocoding!

LA County Land Types

Mark Greninger — Wed, 23 Feb 2011 02:39:31 +0000

Updated December 2012 – Added the Michael D. Antonovich Open Space Preserve and the Santa Clarita Woodlands Park

The Land Types dataset includes various types of land use that are critical for mapmaking and geographic analysis. The data has been created to match parcel boundaries where possible, and digitized from 4-inch aerial photography where more detail was needed.

Important note: This data is still under development and is not complete as of April 2011, and it should not be used for authoritative analysis.

General land types that have been captured include:

Beaches
Golf Courses
Museums & Aquariums
Parks & Recreation Centers
Sports & Event Venues

Colleges & Universities
Schools (Private, Charter, Public)
Hospitals (limited set)
Cemeteries

TV & Movie Studios
Jails & Prisons
Airport Boundaries
Shopping Centers

A full listing of the categories can be found here: Land Types Categories – February 2011 (Excel Table).xlsx

This data is the result of a collaborative county project that began in January 2011 to update and take ownership of this valuable dataset. It is closely related to the Location Management System program, which updates information represented as points. This data is a replacement for the currently licensed Thomas Brothers OWNA layer. It has greater scope, greater accuracy, and will be maintained collaboratively by County departments and various agencies that have true jurisdiction over the actual land types.

The LA County Department of Regional Planning has made a significant enhancement to the land types data through its development of three layers:

Parks, Recreation Centers, and Sports Complexes – 1,340 total
Schools – 2,951 total- see the School Update Process description (.pdf file)
Open Spaces – from the ‘California Protected Areas Database (CPAD)’ (click here for website).

LA County’s eGIS Group developed the boundaries for 110 Golf Courses, and the LA County CIO’s office developed a number of other layers, including cemeteries, colleges, and shopping centers.

Data Access:

Thomas Brothers Cultural Areas (2008)

Mark Greninger — Tue, 09 Feb 2010 02:22:17 +0000

The Cultural Areas layer contains cultural areas from Thomas Brothers. These include features such as major building footprints, airport runways, and dams.

Thomas Brothers Page

Mark Greninger — Tue, 09 Feb 2010 02:19:30 +0000

The data layer contains the page index for the Thomas Brother Map Guide, which references a page number in the paper map book published by Thomas Brothers. This grid, copyrighted by Thomas Brothers, is commonly used to reference the general location of many geographic data types, both in Thomas Brothers and in the real estate, as well as other, fields.

This dataset has been enhanced by LA County CEO Urban Research to include hypothetical page boundaries where Thomas Brothers does not produce map pages, but are still within the county.

Thomas Brothers Page and Grid

Mark Greninger — Tue, 09 Feb 2010 02:16:36 +0000

The data layer contains the page and grid index for the Thomas Brother Map Guide, which references a page and grid in the paper map book published by Thomas Brothers. This grid, copyrighted by Thomas Brothers, is commonly used to reference the general location of many geographic data types, both in Thomas Brothers and in the real estate, as well as other, fields.

This dataset has been enhanced by LA County ISD eGIS to include hypothetical page and grid boundaries where Thomas Brothers does not produce map pages, but are still within the county.

Library Service Area Boundaries

Yoko Myers — Tue, 08 Dec 2009 01:53:23 +0000

County of Los Angeles Public Library Service Areas consists of 89 Service Areas.

County of Los Angeles Public Library serves all unincorporated communities (except for Altadena Library District and Palos Verdes Library District) and 51 contract cities.

Current Service Area is under review (as of 2010/1/20).