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Basic Mapping With ArcGIS Online

The dominant company in geographic information systems is ESRI, which was one of the pioneers of GIS in the late 1960s. If you do GIS professionally, you will probably be working with ESRI software.

ESRI's cloud-based service is called ArcGIS online, which is available by subscription, and which can be used to create web maps and perform some types of spatial analysis. The ArcGIS Online web app makes web map creation comparatively easy by providing online access to a flexible visualization and analysis tool, as well as easy access to both public and proprietary data.

This tutorial will cover the creation of basic maps in ArcGIS Online.

• Getting ArcGIS Online
• Single Symbol Point Maps
• Categorical Pictogram Maps
• Quantitative Bubble Maps
• Mapping Shapefiles
• Living Atlas Layers
• Starting a New Map
• Reopening a Map

Getting ArcGIS Online

You can get an ArcGIS Online account in one of three ways.

Enterprise Account

If your school or employer has an ESRI site license, you can get an account from your instructor or IT staff. The video below shows how to log in to ArcGIS Online using an enterprise account such as that used at The University of Illinois.

ArcGIS For Personal Use

If you do not have access to an enterprise account, you can purchase an annual license from ESRI for personal use (as opposed to commercial use) for $100 that includes not only authorization for their desktop products (ArcMap and ArcGIS Pro) but also ArcGIS Online. The ArcGIS Online subscription comes with a limited number of credits, although you can purchase more as needed for a significant cost.

Free Public Accounts

ESRI provides free public accounts that provide basic capabilities to give you a feel for what ArcGIS Online can do. Public accounts include no proprietary data or analysis tools, which limits users to creating simple maps.

Geospatial Data

To create a map, you need geospatial data.

Geospatial data is what is where. Geospatial data indicates what things or characteristics (what) are at specific locations on the surface of the earth (where).

Single Symbol Point Maps

Creating a CSV File In Excel

Comma-separated variable (CSV) files are spreadsheet files that can be saved from any desktop spreadsheet program (like Excel) or from Google Sheets. CSV files that contain addresses or latitudes / longitudes can be imported as layers in ArcMap.

Latitudes and longitudes are numeric coordinates that can be used to uniquely identify locations on the surface of the earth. Latitude is the angular distance of a point north or south of the equator, and longitude is the angular distance of a point east or west of the prime meridian in England.

This video shows the creation of a CSV file in Excel of houses of worship in the Farmingdale, NY area.

1. Create a new Blank Workbook in your spreadsheet program.
2. Add the headers to each column that represent the attributes you want to map for each location. Add columns titled Latitude and Longitude where you will provide the coordinates for the locations
3. Right click on locations in Google Maps to find the latitudes and longitudes of locations.
4. Add the latitude, longitude, and attributes for each location you want to map
5. When you are done, Save As the file as a CSV (Comma delimited) file under a meaningful name.

Creating a Map with the CSV File

The simplest form of point maps uses a single symbol for all locations being mapped.

1. From your ArcGIS Online home page, select Map to create a new map.
   • In the map viewer, click Add and Add Layer from File.
   • If you have named your location fields latitude and longitude, the app will automatically map your points as dots.
   • If you misspell latitude or longitude, or you want to map your points from addresses or other types of names, you will be given a dialog box asking what fields to use for what types of locations
2. Under Choose an attribute to show, select Show location only
• Under Select a drawing style, click Options and select a symbol to use for the points.
• In the Select a category dropdown, you will see multiple categories of symbols that include simple geometric shapes (like circles), as well as pictograms.
3. If desired, right-click and Rename the layer so that the title of the legend is meaningful.
4. If desired, add labels to the points by clicking on the ellipsis (...) on the layer and selecting Create Labels.
   • Choose a label alignment where there is the least amount of overlap and contention for your particular set of locations.
   • Note that the app uses scale-dependent rendering that will hide some labels if there would be an overlap that would make them illegible. You can see all labels by zooming in to the points.
5. You may want to change the Basemap to something unobtrusive if the base map conflicts visually with the points
6. Save the map under a meaningful name.
7. Share the map with Everyone (public) and copy the shared link that you can e-mail or submit for an assignment.

Categorical Pictogram Maps

Categorical variables divide features into categories. In the example spreadsheet created above the Tradition column is a categorical variable that indicates what religious tradition each house of worship belongs to.

If you have a categorical variable, you can use ArcGIS Online to create a map where the type of symbol varies depending on that categorical variable. Pictograms are small images that have literal or metaphorical relationships to the locations being mapped.

1. From your ArcGIS Online home page, select Map to create a new map.
   • In the map viewer, click Add and Add Layer from File.
   • If you have named your location fields latitude and longitude, the app will automatically map your points as dots.
   • If you misspell latitude or longitude, or you want to map your points from addresses or other types of names, you will be given a dialog box asking what fields to use for what types of locations
2. For categorical variables, you will probably want the Types (Unique symbols) drawing style.
   • For Options click on the icons under each category to choose and size appropriate pictograms.
3. If needed, right-click and Rename the layer to that the title of the legend is meaningful.
4. If desired, add labels to the pictograms by clicking on the ellipsis (...) on the layer and selecting Create Labels.
   • Choose a label alignment where there is the least amount of overlap and contention for your particular set of locations.
   • Note that the app uses scale-dependent rendering that will hide some labels if there would be an overlap that would make them illegible. You can see all labels by zooming in to the points.
5. Consider changing the Basemap to something unobtrusive if the base map conflicts visually with the points.
6. Save the map under a meaningful name.
7. Share the map with Everyone (public) and copy the shared link that you can e-mail or submit for an assignment.

Quantitative Bubble Maps

Quantitative variables are numeric values that count or measure something associated with a feature. In the example spreadsheet above, the Capacity column contains values for the seating capacity of each of the houses of worship.

For quantitative variables, Counts and Amounts (Size) can be used to create bubble maps.

1. From your ArcGIS Online home page, select Map to create a new map.
   • In the map viewer, click Add and Add Layer from File.
   • If you have named your location fields latitude and longitude, the app will automatically map your points as dots.
   • If you misspell latitude or longitude, or you want to map your points from addresses or other types of names, you will be given a dialog box asking what fields to use for what types of locations
2. For Choose an attribute to show, select your quantitative variable.
   • For quantitative variables, you will probably want the Counts and Amounts (Size) drawing style
3. If desired, add labels to the bubbles by clicking on the ellipsis (...) on the layer and selecting Create Labels.
   • Choose a label alignment where there is the least amount of overlap and contention for your particular set of locations.
   • Note that the app uses scale-dependent rendering that will hide some labels if there would be an overlap that would make them illegible. You can see all labels by zooming in to the points.
4. Consider changing the Basemap to something unobtrusive if the base map conflicts visually with the points
5. Save the map with a meaningful name
6. Share the map with Everyone (public) and copy the shared link that you can e-mail or submit for an assignment

Mapping Shapefiles

Many organizations, including federal, state and local governments, make data available to the public as shapefiles, which is an old file format developed by ESRI in the 1990s that is still commonly used for sharing data. A shapefile is actually multiple files, but shapefiles are often packaged as single .zip files for easier distribution.

For this example, we use this shapefile of state election data.

• Download the shapefile to your local storage drive
• Select Add, Add Layer From File to upload the shapefile
• Style the layer based on a field in the shapefile. For this example we will use the winner of the 2012 presidential election (WIN2012), coloring states won by the Republican candidate (Romney) red and states won by the Democratic candidate (Obama) blue, in accordance with common conventions
• As before, zoom, save and share

Living Atlas Layers

ESRI's Living Atlas of the World is a collection of open and proprietary data that is made available in ArcGIS Online. Living Atlas layers cover a wide variety of topics.

Creating a Map

1. Select Map from your ArcGIS Online home page
2. Click the Add button and Browse Living Atlas Layers
3. Search for your topic of interest. For this example we will use 2016 Median Household Income
4. For polygon layers, adjusting the transparency to 25% will permit the base map to be visible and give geographic context to your layer so you know where things are
5. Zoom the map to your area of interest
6. View the legend to see what the colors or symbols mean
7. With many layers, you can click on a region to display a pop-up displaying information about that region

Generalization

Web maps are designed so that you can zoom in or zoom out, and those different zoom levels are numbered, from one showing the whole world, to 21 or greater, which shows building-level detail.

Many Living Atlas layers provide different levels of cartographic generalization based on the zoom level. This scale-dependent rendering technique optimizes the amount of data displayed at different scales, so maps do not appear either too cluttered, or too lacking in detail to be meaningful. With this median household income layer:

• When zoomed in close to an area, this layer displays census tracts or block groups
• Zooming further out, the data is generalized to the county level
• Further out, the data is generalized to the state level
• As with many layers, you can click on a region to display a pop-up displaying information about the region displayed at that particular level of generalization

Adding Map Notes

Map notes are layers of annotations that can be used to point out specific locations or features on a map.

1. Select Add, Add Map Notes
2. Give the map notes layer a meaningful name
3. Pan to the area you want to annotate
4. Select the type of note you want to add in the left pane, then click on the map to add it
5. Give the annotation a meaningful name and, if needed, annotation text
6. When you are done adding notes, click the edit button to stop editing
7. If you later want to add additional map notes to an existing map notes layer, select the layer in the Contents pane and click the Edit button

Finding Latitudes and Longitudes

If you need the latitude and longitude in ArcGIS Online, you can use the Location tool and click on the map to find the latitude and longitude. Those latitudes and longitudes can be pasted into Google Maps if you want to find neighborhood names or get or share street views of a location.

Starting a New Map

When you are done editing a map, if you want to close the existing map and start a new map, save the existing map, and then click the New Map link at the top left.

Reopening a Map

Maps that you save are listed on your Content page in ArcGIS Online. To reopen the map for modification or revision, select the link on your content list and then Open in Map Viewer.