Tag Archives: thematic mapping
Red, Blue and Purple: mapping the 2012 US Presidential Election
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very time an election occurs, maps become a key component in telling the story, but what type of map best tells the story of the winners and losers? Red/blue choropleths? Areas shaded in an array of purples? Value by alpha maps? Dot density by County? Ultimately, the areas used (e.g. Counties) are arbitrary, exhaust space and dictate the visual pattern we see. We can warp them into cartograms but these sometimes distort geography too much for them to make much sense. The patterns we see are as much a product of the boundaries as the voting patterns of real people in real places. This blog entry explores different ways to map election results and describes a different type of map we made to show the 2012 Presidential election results…it’s a multiscale dasymetric dot density web map (viewable on ArcGIS Online).
Thematic Atlas sample app now available
The Esri Thematic Atlas Sample App is a configurable web application that uses a collection of intelligent web maps with text, graphics, and images to talk about our world. The sample application allows the author to organize maps into groups … Continue reading
Uploading client data to perform thematic mapping on the server
You might have read this blog post about dynamic layers in ArcGIS 10.1 for Server that describes how you can change a map service layer’s symbology on a per-request basis. In this blog post, I’ll describe a JavaScript application that takes dynamic layers to the next step and allows server-side thematic mapping using data from your local machine. Server-side rendering is useful, especially when downloading features onto a client’s browser is expensive. For example, in this particular app downloading all 3,000+ county polygons onto a client’s browser could be very slow, assuming the server is even allowed to send that many features at once.
You can try the application here:
This application allows a client to upload a CSV file onto the server and to draw counties based on an attribute from the uploaded file. As part of that process, the application executes a geoprocessing task which converts the CSV file into a table in a file geodatabase, then sets a join and a renderer to a sublayer in the dynamic map service layer. Note that every draw request that goes to the map service needs to include the full definition of the join and the renderer because requests are stateless. Continue reading
Place and Road Labels above Color Coded Maps
By Sooria Jeyaraman
How many times you have created a color-coded map from our list of close to 6000 variables (yes, I said 6000) and turned it completely opaque to see the colors come to life? There is one small problem with that. Once you set the transparency to 0% then you will not be able to see the roads or places below these colors. How many times have you wondered that it’ll be great if you have a way to look at these without losing your beautiful colors? If you are, you are not alone. Some of you brought this issue to our attention so, as usual, we decided to do something about it.
Sneak Peek: Browsing ArcGIS.com Maps in Business Analyst Online
by Sooria Jeyaraman
As you all know in our latest release we’ve added the capability to integrate ArcGIS.com maps in Business Analyst Online. Now we are stepping up the game and making it much easier to load. You can load the ArcGIS.com maps with a single click. How is that done you may ask? Continue reading
ArcGIS.com Popups and Business Analyst (Identifying Vulnerable Populations) – Part II
by Mehak Sujan
In my previous post, ArcGIS.com Popups and Business Analyst (Identifying Vulnerable Populations) – Part I, I demonstrated an application that identifies geographic areas within the US which are most vulnerable to natural hazards and disasters by taking into account three demographic factors: household income less than $30K, population greater than 65 years, and children less than 18 years. Continue reading
ArcGIS.com Popups and Business Analyst (Identifying Vulnerable Populations) – Part I
by Mehak Sujan
With the ArcGIS API for Flex 2.3 that was just released on April 15th, support for ArcGIS.com popups has been added.
Our team is really excited about this new added support and we want to do something cool to integrate it into the Business Analyst APIs. I’ve written a sample application that demonstrates one way of identifying geographic areas which are most at risk to natural hazards and disasters (e.g. floods, hurricanes, earthquakes, fire, etc) within the country by taking into account demographic factors. It blends together Continue reading
Business Analyst Online API for Flex – Thematic Mapping Sample
by Mehak Sujan
Other than migrating from ArcGIS Server for Flex 1.3 to ArcGIS Server for Flex 2.1, the second key aspect of the Business Analyst Online API for Flex 2.0 has to do with the full redesign of the thematic mapping functionality. What’s new in 2.0 lists all the changes related to thematic mapping such as which class, method and property has been added, removed or modified.
Along with this, we have released a thematic mapping sample application that leverages this new BAO Flex 2.0 API. This sample is provided as-is and can be downloaded from the code gallery. This download includes both the complete Flash Builder 4 project download and README.txt file explaining how to get this project up and running in your environment.
Once you have it up and running, you can start playing with it…
To begin, login using your BAO API credentials. If you don’t have one yet, you can purchase one or get a free 30-day trial subscription here.
When you have logged on, the application loads the thematic mapping layer using the default thematic mapping properties. You can easily change the variable you want to thematically map along with other properties such as the color scheme and its transparency level, and the classification type and number of classes if you don’t want the default settings…
The thematic mapping layer automatically updates as you pan or zoom on the map. Based on your map scale, it is also intelligent enough to change the geography level that is mapped with the ‘Auto Select’ option and grays out the geography levels that can’t be rendered at that scale…
For example, after zooming to the north-eastern part of the country, the thematic layer automatically redraws to show counties (the recommended geography level for the current map scale) instead of states for that map area…
The legend also automatically updates and you can hover over any county to see its Total Population for 2010 and its details under the Description tab…
You can thematically map any supported variables available by your BAO API subscription (most variables are supported for thematic mapping except some Market Potential and Consumer spending variables). You can also quickly change the display of the variable as a percent, average or index based on the type of variable if you don’t want the raw number value to be displayed…
Try downloading the application to play with it and happy mapping!
Mehak
