Dennis Decelle
GEOG385
American River College
Fall 2014
Nevada County Grown
Accessing Locally Produced Food in Nevada County
Project Summary
Western Nevada County is home to a number of small farms and ranches that offer a
variety of sustainably grown fruits and vegetables, and grass fed, hormone and antibiotic free
meats. Some are certified organic and most of them go above and beyond organic standards
without going through the hassle of organic certification. There are many ways to access these
producers including the various farmer’s markets around the county as well as grocery stores
and restaurants supplied by them. The focus of my project is to help the user find nearby
options for supporting local farms and ranches.
My web map allows the user to interactively drag and drop a point on the map for their
location and enter a buffer distance to find the nearest farm/ranch, farmer’s market, grocery
store or restaurant. The user can then click on a selected feature to open a pop-up window for
more information such as name, address, contact information, days and times of farmer’s
markets, whether a farm is certified organic or if a farm or ranch offers direct sales at their
location. There is also the option of viewing the attribute tables to compare features in the
current extent and highlight features on the map.
Purpose of Project
I decided to do this project because I believe it is important to know where your food
comes from and how it is produced, and to support your local economy. I also wanted to
expand on the functionality of a database that I created previously and explore how it could be
applied in an interactive web map application. As a resident of Western Nevada County I
wasn’t aware of all the local food options or that this is home to more than 50 small-scale
producers. I created this web map application to help both locals and visitors find fresh, local
food sources and possibly foster a deeper connection to the community through food.
Data Development and Map Creation
Data Sources:
 National Atlas: Major Roads (Interstates, US Highways, State Highways)
 Cal-Atlas: Lakes, Rivers, Creeks, CA Counties
 Nevada County GIS: Nevada County Roads, Parcels, Parks, Community Boundaries
 USGS: Digital Elevation Model with Nevada County in its extent
 The Farm/Ranch, Farmer’s Market, Restaurant and Grocery Store point data was
created by me for a previous database design project. Most of the information
was gathered from the Nevada County Grown website and annual Farm Guide for
2013 and entered into tables. The tables were then joined to an Address Points
feature class from Nevada County GIS to create the point features.
The first step was to preprocess the data. I added CA Counties, Major Roads and
Hydrologic features, clipped them to a rectangular area around Nevada County and exported
them to my project geodatabase. I then converted the Nevada County GIS data from shapefiles
to geodatabase feature classes and clipped the USGS DEM to Nevada County and exported it to
the project geodatabase. I converted the DEM to hillshade, set it to 60% transparency and
added it to the map on top of the Counties, Parks and Community Boundaries to add depth to
the map. When I imported the point data I realized that the tables contained all the fields
combined from the table joins with the Address Points layer. I went through each table and hid
all the unnecessary fields and made the field aliases more user friendly. (This created problems
that I’ll explain later.)
With my data compiled and processed I was ready to design my map. One problem I ran
into was that the Major Roads layer did not line up with the Nevada County roads layer. I
remedied this by turning the Highways layer off at 1:80,000 and Nevada County Highways on at
1:79,999. Unfortunately this meant that I had to style two different highway layers. Also the
lakes and rivers labels would only display as all capital letters even though the box for all caps
was unchecked. Other than that it was just a matter of deciding what zoom levels to set for
each layer and label and what symbols and colors to use. I set zoom levels for all the layers and
labels so that more details emerged as the user zooms into the map.
1:250,000
1:80,000
1:3,000
Web Services Development
Creating the Map Service was pretty straightforward once the map was styled, labeled
and zoom levels were set. I navigated to File/Share As/Service… and stepped through the
wizard. When I got to the Service Editor window I reviewed the General Tab and made sure the
Start Service Immediately box was checked.
In the Capabilities window I unchecked KML and left Mapping checked and added some
metadata to the Item Description. I took the default settings for everything else and clicked
Analyze. Since there were no errors I clicked publish and hoped for the best. I opened my map
service in ArcGIS Server Manager and reviewed all the information and settings. Everything
looked good!
The next step was to create a geoprocessing service that allows the user to enter their
location and a search distance. I created a new point feature class for the point that the user
drags and drops at their location and then created an empty polygon feature class as the buffer
distance output. I opened a new model and added the buffer tool and the empty point feature.
The point feature was set as a parameter and the data type was set to Feature Set to allow the
user to input their location as a drag and drop point.
I then added a search distance variable and set the data type to Linear Unit.
I made it a parameter and entered a default search distance of 5 miles. I added the empty
polygon feature class as the Buffer Output and made it a parameter also.
After running the model I symbolized the buffer polygon output to hollow with a grey outline
and saved it as a layer file. I set the buffer output to reference this layer file when symbolizing
the buffer polygon.
When I confirmed that the Buffer model worked I copy/pasted it as an input into another
model which selects all the Farms/Ranches, Farmer’s Markets, Restaurants and Grocery Stores
that are within the Buffer distance and copies them to a new feature class.
I ran the model and it worked as I had hoped. I then symbolized the newly created features
(the selected features within the buffer distance) with meaningful graphic symbols
Now the model was ready to be published as a geoprocessing service. I opened the
Geoprocessing Results window and right clicked on the model that I just ran and clicked Share
As… Geoprocessing Service. Again I stepped through the wizard to the Service Editor window.
I made sure “View results with a map service” was checked in the Parameters window and had
to enter some metadata and choose correct the input mode for each parameter in the model.
Web Application Design
Now that I had a published map service and geoprocessing service it was time to create
my web application. I launched ArcGIS Viewer for FLEX and added the Oceans base map from
ArcGIS Online, a muted gray background that doesn’t compete with the operational layers. I
added my Nevada County Grown map service folder from ArcGIS Server for Operational Layers
and chose an extent that zooms to the point features. The pop-up windows were configured to
only display the attributes most useful to the user for each point feature class. In the Layout
window I added the attribute tables for the point features and configured the tables the same
as the pop-up windows. I added the Legend, Layer List and Geoprocessing widgets and then
copy/pasted the REST endpoint of my Geoprocessing service from ArcGIS Server Manager into
the Task URL space in the Geoprocessing widget. I saved all my settings and opened the
application in a web browser.
Web Application opened in browser
Using the Web Application
The user can find the nearest Farms or Ranches, Farmer’s Markets, Restaurants or
Grocery Stores using the Geoprocessing widget. The user drops a location point on the map
and enters a search distance. All the point features within the search distance radius are
selected and symbolized with meaningful graphic symbols: tractor crossing sign for farms and
ranches, knife and fork sign for restaurants, grocery cart sign for grocery stores and a green flag
for farmer’s markets.
Selected Features within 3 miles of user location point.
The user can then zoom to the features and view their attributes in the tables or click on a
feature to see the attributes in a pop-up window. The attribute tables list all features in the
extent and selecting features in the attribute table highlights the features in the map. You can
also zoom to a feature by double clicking on the feature.
Selected features highlighted in map
Discussion of Challenges, Problems, Issues, Resolutions, Outcomes
After publishing the map service successfully and previewing it in the FLEX viewer, I
decided to make some changes (make point symbols simple solid circles and hide unnecessary
fields) and publish it again. Now the attribute tables were empty except a message stating that
there were no features within the map extent which was not the case. I tried republishing the
map but that didn’t resolve the issue. I retraced my steps and realized that the only major
change I made was hiding some fields. I made all the fields visible again, republished the map
and then opened it in Google Chrome. Now it only displayed the ESRI base map of the entire
world. I tried copy/pasting the URL into Internet Explorer and thankfully my web application
was fully operational again with populated attribute tables.
Another issue was that the buffer polygon was supposed to display as hollow with a
dark grey outline but in the web application it had a faint grey outline which is virtually
impossible to see. You have to rely on the different symbols of the selected features to know
what falls within the search distance radius. Also I was hoping that the selected features would
be highlighted in the attribute table like they are in ArcMap so you could easily compare what
the selected farms and ranches had to offer such as direct sales, CSAs or organic certification.
However you can select features in the table to highlight them on the map. I also didn’t realize
that you couldn’t zoom in far enough to turn on the labels of the point features, but since I
included pop-up windows it wasn’t a big deal.
Conclusions
My goal was to create a functioning web application and I was successful, but there is
some added functionality that in retrospect I would add if I had more time. First I would add a
select by attribute query so you could select all farms or ranches that are certified organic,
offered a CSA subscription or offered direct to consumer sales at the farm/ranch location. I
would also add a hyperlink to the URLs in the pop-up windows so you could get to the website
with one click. Since the selected set of features aren’t highlighted in the attribute table, I
would somehow enable the geoprocessing widget to output tables of the selected features.
The most important improvement, although it is probably a complicated process and I have no
idea how to do it, would be to create a search distance by drive time or by miles on a road
network. Since much of Nevada County is in mountainous terrain, this would be a more
realistic way to find the nearest features than a search by buffer distance (as the crow flies).