Title
Ione Commercial Survey:
Calculating Commercial Square Footage in the City of Ione

(website best viewed in Internet Explorer 8 or above)

Author Information
Devan Morris
American River College, Geography 350: Data Acquisition in GIS; Spring 2010
devmorris@gmail.com

Abstract
This is the summary of the entire paper. All the following sections should be represented by a single sentence or two, with the exception of background and references. Write this last.

Introduction
Question:  How much commercial square footage is within the City of Ione; where are the commercial buildings located; and what are their uses.  The company I am employed with was hired by the City of Ione to do an inventory of all the commercial land uses throughout the city and come up with an estimated amount of commercial square footage.  City officials in Ione want to know if there is enough zoned commercial land within the city to meet the needs of a future residential development projects.   Our scope as consultants was to collect as much information on existing land uses as possible, conduct a field survey to identify existing business and vacant buildings, and develop a method to calculate how much commercial square footage is within the City using GIS.  GPS receivers will be used to identify the location of commercial buildings throughout the town.  My colleague and I would then make a note of the land use on a spreadsheet along with the GPS waypoint number.  All this data would be imported into GIS and the buildings digitized.  Finally, a standardized classification method would be incorporated to give each commercial building a land use.

Background

The City of Ione is located in the foothills of the Sierra Nevada Range south east of Sacramento in Amador County.  It has a population of 7,129 as of the 2000 Census and encompasses an area of 4.8 square miles.  Ione was historically an important trading center for miners coming down from the Mother Lode and Southern Mines.  The economy is now centered on retirees, tourism, the Mule Creek State Prison, and the California Department of Forestry and Protection facility (Wikipedia, 2010). Ione is anticipating the development of portions of Rancho Arroyo Seco and an influx of new residents over the next decade.  In order to meet the needs of these new residents the city wants understand what existing commercial uses are located within the city in order to understand if zoning for additional commercial space will be necessary.  Prior to our project, the city only had parcel line data and business licenses available.  Our project would integrate these two pieces of data by locating where buildings with businesses existed, their square footage, land use and parcel number.

A literature review on how to conduct a project like this was undertaken to give some more insight as to how it might be carried out.  It was determined that all the methods presented were impractical for covering the entire town as they required actually entering the building and taking measurements.  Searches for methods on how to utilize GIS to calculate building square footage also came up empty.  Due to this it was necessary for use to visualize and create our own methodology to determine how best to go about requiring the information we needed.  It was decided by the City that the best classification method to categorize commercial uses would be the Shopping Center Development Hand Book, 1999.   This would allow us to break each usage down into a main category and additional sub categories in which the data could be further analyzed. 

Actually using the data to make predictions about market demand for commercial services was beyond the scope of this project.  I was unable to find any related projects or literature conducted by others that did what this project was attempting to accomplish.  Most attempts at identifying building footprints using GIS are done using LIDAR technology (Palmer & Shan, 2002).  However, given the small size of Ione and the cost of conducting a full on LIDAR imaging of the area, it was determined that this method would be too costly.  Ultimately we decided to develop our own methodology to determine building square footage using the technique outlined below.

Methods
A methodology was developed prior to beginning the survey in order to break the project down in to manageable steps:

1) Find existing data      

2) Create database list

3) Field survey to verify existing data

4) Locate vacant commercial sites, unlisted businesses

5) Categorize land use

6) Import GPS points in to GIS

7) Heads up digitization of building footprints

8) Calculate square footage

9) Check accuracy against existing data

10) Analyze data for additional information

1) Find Existing Data

The City of Ione had business license data that I was able to use to start building a data base of commercial land uses within the town.  They provided me an Adobe PDF document full of business license data such as owner, business name, address and contact information.  This information was then added to an Excel spreadsheet that would serve as the master database for this project. 

In addition to the information provided by the City, I conducted a research for additional unlisted businesses using Google Map’s local listing search engine.  This provided additional home businesses and more recent businesses that might not have licensed themselves with the city yet.  This data was collected and entered into the master spreadsheet list as well.  All the business listings were then given back to the City planning department to double check and make sure all known businesses were on the list. 

2) Create database list

It was decided based on the scope of the project that the following fields would be incorporated into the master spreadsheet:

ID- A unique ID for each business

Business Name- Name of the business

Address- Originally broken down into separate fields (i.e. number, direction, street, suffix etc.) to make easier for geocoding.  However, I opted for a field survey instead and usually hid this field

GPS Chelsey- A GPS point that was marked by Chesley’s receiver and would be used to join spreadsheet to GPS points in GIS

GPS Devan- A GPS point that was marked by my receiver and would be used to join spreadsheet to GPS points in GIS

Business Category- Using the Shopping Center Development Handbook, 1999 each business land use would be given a category and sub category

Business Subcategory- See above

Parcel APN- The assessor parcel number was included for the location of the business

Number of Businesses on Parcels- Some businesses shared a building and were located on the same parcel

Building Square Footage- The square footage of the building footprint calculated in GIS

Number of Stories- Used to calculate total square footage

Additional Notes- Anything that might come up during the survey process could be noted in this field 

All data collected in the initial research state was added to this spread sheet with blank spaces left for the information that would be collected from the survey and GIS.  By outlining all the information that would be needed and creating a clearly defined methodology I believe I was able to limit the amount of time needed out in the field.  Because this project was part of my work any extra time spent in the field would have increased the cost of the project to my employer.  It was therefore necessary that I had a well defined plan with lots of redundancy to reduce the need to go back to Ione and recollect information.

3) Field survey to verify existing data

Next my coworker and I prepared to conduct a field survey of the City of Ione.  We both had GPS units to ensure redundancy and accuracy within the data.  She was equipped with a Garmin GPSMap 60CSX while I had a Garmin GPS 76. Extra batteries were brought along and a physical map of downtown Ione that I had put together prior to us leaving.  This map would be used to navigate the city and serve as yet another way we could record the location of businesses in case we had any problems with GPS data we collected.  Again, redundancy was a big factor in this project in order to reduce costs and ensure we did everything correctly the first time through. 

Example of a back up map that was brought along and marked up; the map was especially helpful for buildings that contained multiple businesses.

4) Locate vacant commercial sites, unlisted businesses

Information was entered on the spreadsheets.  A GPS point was marked outside each business and then the waypoint was marked within the spreadsheet so we would know what GPS waypoint went with which business.  This was done for every business within the City of Ione.  In addition basic information about the business type was included based on our own observations.  This information would later be used to create a classification system for all the commercial uses.  Buildings with unique features such as being part of a plaza or being vacant were noted in the additional notes category.  The spreadsheets above are only the front side.  Additional information including space to add vacant buildings was put on the back side of the spreadsheet.

5) Categorize land use

All information collected in the survey was then added into the master spreadsheet.  As noted above, the Shopping Center Development Hand Book, 1999 was used to create the classifications needed to identify the category of business use.  Each major category was then further subdivided into subcategories in order to get the best idea of what was actually taking place at the site.  All these categories were applied by my coworker and myself acting as expert systems (in this case our experience with land planning and development) to make a determination into what category a business would be classified as.  Although classification may seem like a straight forward process, often times the actual use of a business does not easily fit into one category.  An example would be a gas station that has a convenience store selling prepackaged food and other merchandise.  Would this land use be considered Automotive Service or Food Service?  Our general rule was the major source of revenue that sustained the business would be considered its final use.  In the above case, a gas station probably makes more money selling gas than food so it would be classified as Automotive Service.

6) Import GPS points in to GIS

The waypoints collected with both GPS receivers were imputed into a GIS through a program called Expert GPS.  This program is a simple interface that allows GPS units of any brand to be connected to a computer, the data downloaded of the receiver, then converted into a multitude of formats.  For this project the data was converted into a point shapefile that could be read by ESRI ArcInfo. 

The waypoints were then joined to their corresponding unique waypoint ID numbers in the master Excel spreadsheet.  This allowed all the data we collected in the field to be show on the map and allowed me to identify were the different businesses were located. 

7) Heads up digitization of building footprints

Using the GPS data as a way to find their corresponding buildings on the high quality 6 inch orthophoto we had done for the city, I was able to start to heads up digitize the commercial buildings within the city of Ione.  For buildings that had multiple businesses under one roof, an effort was made to best divide the building to that each business would get its own polygon and information.   Each building was carefully traced using the create polygon editing tool and the project of the map was changed to Teale Albers Conical Projection designed for California in order to best preserve the area of the imagery and give the most accurate square footage.  The secondary map was especially useful in this process for identifying buildings where its corresponding GPS point had a high level of inaccuracy.

8) Calculate square footage

ArcMap was used to calculate the geometry for each of the created polygons representing the building areas.  This was done by adding a field then using the field calculator to calculate the area in square feet.  This value was then multiplied by the number of stores to give an overall estimation of the square footage of each commercial site.  This information was then copy and pasted into the master Excel spreadsheet.

9) Check accuracy against existing data

The calculated square footage of the heads up digitization was then calculated against a sample of known values.  Unfortunately the City of Ione only had actual square footage for the Pharmacy building and the Ione Plaza, both fairly new develops and not reflective of all the architecture found throughout the City.  Given these constraints we were unable to determine how accurate our data actually was.  Our data represents and estimation of building square footage which may be different than actual usable commercial square footage and should be seen as a best guess to what is actually available.  Without actual building measurements, it is impossible for use to know what the actual square footage is.  However, I believe our technique does give a good idea of what is currently within the City of Ione.

City of Ione:

            Ione Pharmacy- 8,750 sq ft

            Ione Plaza- 23,570 sq ft

GIS building footprint digitization:

            Ione Pharmacy- 9,148 sq ft (1.05)

            Ione Plaza- 24,210 sq ft (1.03)

For the two buildings we did have data for our method of measuring square footage was only 5 percent off for the Pharmacy and 3 percent off for the Plaza.

Results
10) Analyze data for additional information

Below if the final spreadsheet presented to the city.  All this data was joined to the building footprints and exported as a new shapefile that the city could use to get a better idea of where commercial space was located within the town.  This method was chosen if the city wished to further analyze the data we gathered and use it in additional applications.  Since the city contracted out to a private planning firm, they have access to ArcGIS and Microsoft Excel.

ID	Business Name	Address	Business Category	Business Subcategory	Parcel APN	Number of Businesses on Parcel	Building Square Footage (incl. 2nd Story)	Number of Stories	Additional Notes
1	A Second Look	28 W. Main Street, Ione, CA 95640	General Merchandise	Variety Store	004147008000	1	2596	1	Going out of business
2	Amerigas	10835 Highway 49, Jackson, CA 95642	N/A	N/A	N/A	N/A	N/A	N/A	Not in Ione
3	Bank of Amador	33 W. Main Street, Ione, CA 95640	Financial	Bank	004101002000	1	2226	1
4	B & W Financial Service	34 S. Buena Vista Street, Ione, CA 95640	Financial	Tax Preparation	004147007000	2	1315	1	Shares building with Kristi Root
5	C & P Taxes & Accounting	19 E. Main Street, Ione, CA 95640	Financial	Tax Preparation	004102005000	1	1473	1	2 stories with 1 story in use
6	Castle Cuts	31 E. Main Street, Ione, CA 95640	Personal Services	Hair Salon	004102007000	1	1501	1
7	Castle Oaks Golf Club	1000 Castle Oaks Drive, Ione, CA 95640	N/A	N/A	N/A	N/A	N/A	N/A	Not commerical space
8	Clarks Corner	12 W. Main Street, Ione, Ca 95640	Food Service	Coffee/Tea	004147004000	1	2446	1
9	Coldwell Banker	102 W. Main Street, Ione, CA 95640	Financial	Real Estate	004145003000	2	1107	1	2 stories with 1 story in use
10	Curves	28 E. Main Street, Ione, CA 95640	Entertainment/Community	Health Club	004151009000	2	1358	1
11	Elements Skin Care Salon	14 W. Main Street, Ione, CA 95640	Personal Services	Hair Salon	004147003000	3	868	1	Shared building with Woof!
12	Eva Marle's Barber Shop	26 W. Jackson Street, Ione, CA 95640	Personal Services	Barber Shop	004152009000	1	719	1	1/2 of building used
13	Farmer's Insurance	17 S. Buena Vista Street, Ione, CA 95640	Financial	Insurance	004145003000	2	764	1	Dusty Stahl Insurance
14	Kristi Roots Insurance	34 S. Buena Vista Street, Ione, CA 95640	Financial	Insurance	004147007000	2	1477	1	Shared with B & W Insurance
15	Finch's Body Shop	313 W. Jackson Street, Ione, CA 95640	Automotive	Automotive Repair	004141001000	1	4077	1
16	Fran & Kathleen's Grill	4 Plymouth Highway, Ione, CA 95640	Food Service	Restaurant	004090002000	1	2424	1
17	Gold Country Dentistry	21 Plymouth Highway, Ione, CA 95640	Offices	Dental	004041008000	1	1648	1
18	Golden 1 Credit Union	321 Preston Avenue, Ione, CA 95640	Financial	Bank	004080041000	7	2357	1	Plaza #1
19	H & R Block	23 W. Main Street, Ione, CA 95640	Financial	Tax Preparation	004101004000	2	1534	1	Shares building with Don Luis
20	Heirloom Inn	214 Shakeley Lane, Ione, CA 95640	Accomodations	Inn	004080009000	1	2222	1	Weddings only
21	Howard Properties	338 Preston Avenue #A, Ione, CA 95640	N/A	N/A	N/A	N/A	N/A	N/A	See Ione Brewery Building #58
22	Ione Ace Hardware	347 Preston Avenue, Ione, CA 95640	Building Materials/Garden	Hardware	4080010000, 4080038000	1	12022	1	2 parcels
23	Ione Auto Parts	20 E. Main Street, Ione, CA 95640	Automotive	Automotive Parts	004151010000	1	3186	1
24	Ione Café	15 Preston Avenue, Ione, CA 95640	Food Service	Restaurant	004144001000	2	1076	1	Shares building with Salon
25	Ione Chinese Restaurant	335 Preston Avenue, Ione, CA 95640	Food Service	Chinese Restaurant	004080041000	7	1571	1	Plaza #2
26	Ione Chiropractic	119 Clay Street, Ione, CA 95640	Offices	Medical	004106027000	1	790	1	Home business
27	Ione Hotel, Steakhouse & Bar	25 W. Main Street, Ione, CA 95640	Accomodations/Food Service	Hotel/Restaurant	004101003000	1	9616	2	Second story in use
28	Ione Laundromat	329 Preston Avenue #6, Ione, CA 95640	Personal Services	Laundry	004080041000	7	2090	1	Plaza #4
29	Ione Nails	333 Preston Avenue, Ione, CA 95640	Personal Services	Nail Salon	004080041000	7	1722	1	Plaza #3
30	Ione Pharmacy	307 Preston Avenue, Ione, CA 95640	Drugs	Drugstore/Pharmacy	004080042000	2	4325	1	Shares with Clinic
31	Ione Plaza Market	313 Preston Avenue, Ione, CA 95640	Food	Supermarket	004080041000	7	12744	1	Plaza #7
32	Ione Sudsy Buggy	414 Church Street, Ione, CA 95640	Automotive	Car Wash	004261010000	1	1972	1	In front of Dave's
33	Ione Trading Post	39 Preston Avenue, Ione, CA 95640	Automotive	Gas Station	004041006000	1	1731	1
34	Lodi Memorial Primemed Clinic	305 Preston Avenue, Ione, CA 95640	Offices	Medical	004080042000	2	4823	1	Shared with Pharmacy
35	Nature's Own Way	104 S. Church Street, Ione, CA 95640	N/A	N/A	N/A	N/A	N/A	N/A	Not found
36	Oak Tree Homes	13 W. Main Street, Ione, CA 95640	Financial	Real Estate	004101006000	1	1203	1	Twin Wolf
37	Paisano's Pizza	325 Preston Avenue, Ione, CA 95640	Food Service	Pizza	004080041000	7	2108	1	Plaza #5
38	Pets & Stuff	102 E. Main Street, Ione, CA 95640	Other Retail	Pet Shop	004153001000	1	5554	1	1/2 of building used
39	Pizza Factory	10 E. Main Street, Ione, CA 95640	Food Service	Pizza	004151011000	1	5522	2
40	Platinum Hair	14 W. Main Street #2, Ione, CA 95640	Personal Services	Hair Salon	004147003000	3	781	1	Shared with Elements/Woof!
41	Rendevous Primitiva Arms	17 W. Main Street, Ione, CA 95640	Hobby/Special Interest	Gun Shop	004101005000	1	3026	1
42	Select Payment Services	17 E. Main Street, Ione, CA 95640	Other Retail	Office Supply	004102006000	1	1246	1
43	Spoiled Rotten	15B Preston Avenue, Ione, CA 95640	Personal Services	Hair Salon	004144001000	1	1366	1	Shares building with Café and Church
44	Subway	321 Preston Avenue, Ione, CA 95640	Food Service	Sandwich Shop	004080041000	7	1618	1	Plaza #6
45	Tilly's Club	18 Main Street, Ione, CA 95640	Food Service	Cocktail Lounge	004147002000	1	3185	1
46	Valley Pacific Petroleum	349 Preston Avenue, Stockton, CA 95206	Automotive	Gas Station	004080031000	1	2905	1
47	Volcano Vision	24 W. Main Street, Ione, CA 95640	Home Appliances	Cable/Internet	004147009000	1	1250	1
48	Windows Décor & More	73 S. Ione Street, Ione, CA 95640	Building Materials/Garden	Home Improvement	004151009000	2	714	1
49	Woof Dog Grooming	14 W. Main Street, Ione, CA 95640	Personal Services	Pet Grooming	004147003000	3	460	1	Shared building with Elements
50	Robyn's Nest	106 W. Main Street, Ione, CA 95640	Personal Services	Hair Salon	004145009000	1	518	1	First half of building vacant
51	Don Luis Mexican Resturant	21 W. Main Street, Ione, CA 95640	Food Service	Mexican Restaurant	004101004000	2	1915	1
53	Viola Rose Flowers	24 E. Main Street, Ione, CA 95640	Other Retail	Florist/Plant Store	004151004000	1	3077	1	22 & 24 E. Main Street
55	Body Therapy for Energy	21 S. Sacramento, Ione, CA 95640	Personal Services	Massage	004141006000	1	535	1	Not familiar w/ this business
57	Tommy's Garage	340 Preston, Ione, CA 95640	Automotive	Automotive Repair	004090001000	1	3686	1
58	Ione Brewery Building (J.H. Landgraf)	338 Preston, Ione, CA 95640	Vacant	Vacant	004090020000	0	6040	2	Vacant
59	Vacant auto garage, gas	116 W. Main Street, Ione, CA 95640	Vacant	Vacant	004145001000	0	1150	1	Vacant
60	Hunt & Sons	117 Jackson Street, Ione, CA 95640	Automotive	Automotive Repair	004145006000	1	4799	1
61	CC Creations	12 E. Main Street, Ione, CA 95640	Other Retail	Fabric Shop	004151002000	1	1266	1
62	Vacant thrift store	14 E. Main Street, Ione, CA 95640	Vacant	Vacant	004151002000	1	1376	1	Shared building with CC Creations, vacant
63	Vacant (Daniel Stewart Co. Store)	18 E. Main Street, Ione, CA 95640	Vacant	Vacant	004151013000	1	2552	2	Vacant
64	Vacant	15 W. Main Street, Ione, CA 95640	Vacant	Vacant	004101005000	2	721	1	Vacant
65	Dave's Custom Shop	414 Church Street, Ione, CA 95640	Automotive	Automotive Repair	004261012000	1	6629	1	Vacant

It was found that the total square footage for the City of Ione using our method of calculation was 154,982 sq ft.

For comparison, the average Wal-Mart store is 102,000 sq ft (Wal-Mart, 2006)

A further break down of land use was also visualized using a pie chart to better give an idea to what commercial uses are predominate within the City of Ione.

A final map was also presented to the city showing where the commercial buildings were located and their business names.  This method of data visualization was chosen because it easy and quickly presented the observer with the location of businesses and their building footprint.

Analysis
Overall I felt that this project was successful in giving an estimate of how much commercial square footage is within the City of Ione.  However, I feel that it is best if the user of this information understands that it is an estimation and that the limitations we encountered trying to confirm the accuracy of our data makes it only an estimation and not an actual calculation of square footage.  Because of the different ages and architectural styles of buildings found throughout the city, the process we used to digitize building footprints through an orthophoto might not actually represent the actual usable square footage of a building.  Thick brick and masonry walls could reduce the amount of actual square footage available. 

Another problem that I encountered was the actual GPS receivers themselves not giving an accurate location.  Since I had a back up map while in the field, this was not such a major issues but it was still disconcerting to see how many points were actually off by a pretty substantial margin.  I think this is because many of the older buildings located along Main Street had metal awnings and canopies, in addition to glass store front windows.  This caused the single to bounce off these objects and create distortion in the data collected.  If I were to conduct this project again I would take measurements in the street with an unobstructed view of the horizon so the exact location could be better calibrated.  Also, using a high end device like a Trimble unit would also help alleviate this problem.

Conclusion
I believe that taking actual physical measurements of some buildings and creating a sample base on which we could measure the accuracy of our data would be a good first step in fixing the problem of usable space vs. building footprint.  This would also allow for an accuracy assessment to be done and the data adjusted to within a margin of error.  If I had more time with this project I would contact local real estate agents who might better know the actual square footage of some of these buildings as well. 

As GIS and aerial photography become more ubiquitous in everyday life I think it is important to study the limitations of collecting data from these sources of information.  As my project demonstrated, it is important to know your target area and understand that some of the methods used might lead to results that are less than accurate.  Future research should be conducted on how accurate taking measurements from remotely sensed imagery actually are.  Also, it should be noted that it is impossible to have a completely clear way of classifying things such as land use.  Although standardization is helpful in making sure everyone identifies something in the same way, it lacks flexibility to cover the wide range of uses that actually exist in real life. 

Overall I enjoyed this project and hope to continue using the techniques I learned in this class throughout my career. 

References
Casazza John A. and Spink Frank H., 1999.  Shopping Center Development Hand Book, 1999.  Urban Land Institute. ISBN: 0874208521

Ione, California. Wikipedia, 2010.  Accessed on 5/14/2010

Palmer, Trent C. and Shan, Jeffery, 2006.  A Comparative Study on Urban Visualization Using LIDAR Data in GIS. The Urban and Regional Information Systems Association Journal, Volume 14 Number 2-2.

Wal-Mart Stores Inc., 2006. 2006 Annual Report: Building Smiles.  Wal-Mart Stores Inc. Annual Report to Shareholders.