This post will demonstrate how to use our web based GIS application software-ArcGIS Online to summarize Point data as well as visualizing the aggregate points in each polygon feature on a map.
For sample data to practice, Click this link to download this zipped shapefiles: GrazingSpots.ZIP, West Africa.ZIP
(Kindly attribute this data to www.mapsnigeriainitiative.wordpress.com)
Sign into ArcGIS Online account (You must be subscribing to an organizational account to be able to perform analysis in ArcGIS Online). Click on Map to open a new map.
Let us look at our data in the Contents window. We have a Point feature layer- Grazingspots-which represent major grazing spots within the geographical extent. Below is a polygon map comprising the different countries that make up the West African sub-region.
Our task is to summarize the number of points per polygon and visualize this result on the map using ArcGIS Online.
Click on Analysis (red box 1). The Perform Analysis window will open, then click on Summarize Data (red box 2) and under it click on Aggregate Points (red box 3).
In Option 2, we select the polygon layer as that is the layer containing the countries. Option3- Add statistics and its an optional field. For the demo, the dataset contains information on the numerical sizes of the livestock at the mapped grazing spots. Headcount represents the numerical size in the wet months and Drycount in the dry months when migration to the south takes place. Click RUN ANALYSIS
The new layer-Summarize (red boxed) is added. The different circles represent the total number of points per polygon -the bigger the circle translates to a greater number of Points in Polygon. To create the visualization, Click on the ….. beside the layer and choose Create Labels.
The Label Features window will open. Select the appropriate attribute field for labeling the features. The Label size, color and font attributes can be edited. Click OK
The Cluster markers are now labelled and displayed on the map in the screenshot below.
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