Go up
From the Help Desk - Legend Classification Methods
Posted on Sep 27, 2019 by Admin
Hello readers! This week we provide an in-depth response to a question asking about the legend classification methods in SimplyAnalytics. This response is now part of our Help Center: https://simplyanalytics.zendesk.com/hc/en-us
Question: Can you explain the legend classification methods?
The classification method controls how the data in your map is grouped. Areas on the map are assigned to groups using different classification methods. The colors you see on the map depend on which class is assigned to each area.
There are multiple methods for calculating break points for the data. You can select any of the following from the Classification Method menu:
- Quantiles (Local)
- Quantiles (National)
- Natural Breaks (Local)
- Natural Breaks (National)
- Equal Intervals
- Custom
Quantiles (National): This is the default method used to classify each area on the map, and works for most situations. Breakpoints are calculated so that each category contains about the same number of features. "National" uses a sample of locations from throughout the USA to calculate the breakpoints.
Example: If there are 35,000 ZIP Codes nationally and you have 5 categories the legend is calculated so there are theoretically 7,000 ZIPs in each category.
Quantile classes are easiest to understand, but they can be misleading if the data being mapped is not distributed normally. For example, population counts are usually not suitable for quantile classification because only a few places are highly populated. Use population density or percentages for more meaningful maps.
Quantiles (Local): Breakpoints are calculated so that each category contains about the same number of features. "Local" uses a sample of locations from your current view to calculate the breakpoints. This method usually ensures the map will show more colors. For example, if there are 50 ZIP codes visible on your map, and you choose to display them in five classes, the map will show 10 ZIP codes per color.
Natural Breaks (National): Breakpoints are calculated using a statistical formula that finds groupings and patterns in the data. "National" uses a sample of locations from throughout the USA to calculate the breakpoints.
Natural Breaks (Local): Breakpoints are calculated using a statistical formula that finds groupings and patterns in the data. "Local" uses a sample of locations from your current view to calculate the breakpoints.
Equal Intervals: This method uses equal-size intervals for each class and color on the map. Breakpoints are calculated so that each category has the same range. This method doesn't care if all areas on the map end up sharing the same color.
Example: if the lowest value nationwide is 1 and the highest value is 100 for that specific geography the legend will have 5 equal categories 1 to 20, 21 - 40, 41 - 60, 61 to 80 and 81 to 100
Custom: The user selects their own breakpoints by typing in their own values.To set your own custom breakpoints, you can click in each value’s cell and enter a value of your choice. You can also click the colors to customize how the map looks.
More information on data classification/reference:
https://gisgeography.com/choropleth-maps-data-classification/
More from SimplyAnalytics
Posted on May 31, 2011 by Admin
Kenneth Johnson of the Science, Industry, and Business Library at the New York Public Library recently provided a "boot camp" on the library's market research resources to budding entrep...
Posted on Feb 27, 2015 by Admin
SimplyMap is an excellent tool for market research, and it’s made even more powerful by Nielsen PRIZM data. Nielsen PRIZM is the highest quality market segment data available. Every house...
Posted on May 10, 2016 by Admin
One benefit of data and applications like SimplyMap is the ability to visualize information. In this week’s report, we’ll take a quick look at some branding preferences in contiguous Amer...
Posted on Jun 02, 2016 by Admin
Three weeks ago we utilized the SimmonsLOCAL data set to visualize contiguous America’s mayonnaise brand preference. Staying with the American visualization theme, this week’s report will...
Posted on Mar 14, 2010 by Admin
The GRI team was honored to learn that SimplyMap was included in this year's Choice Outstanding Academic Title List, published in the January 2010 issue of Choice Magazine. This is a grea...
Posted on Sep 08, 2016 by Admin
One of our favorite uses of SimplyMap is to find data that validates our general assumptions and observations. For example, in a previous blog we wrote about the growth of tablet ownershi...
Posted on Dec 02, 2019 by Admin
Hi everybody! We’re back this week with another question from our Help Desk. This time featuring SimplyAnalytics Canada. Let’s get started! Question: How can I analyze all of the PRIZM5 s...
Posted on Jun 02, 2017 by Admin
We will be exhibiting at SLA in Phoenix, AZ on June 18th-20th. You can find the SimplyAnalytics team at Booth #905. Stop by and check out our groundbreaking new interface, have a chocolat...
Posted on Feb 05, 2015 by Admin
In this week’s edition of exploring SimplyMap data, we take a look at America’s coffee drinkers. SimplyMap contains more than 100 coffee related variables, including consumer spending on ...
Posted on May 26, 2016 by Admin
In this week’s report exploring SimplyMap data, we take a look at the variables available relative to internet search engines used. The source of this data will come from the SimmonsLOCAL...