ArcGIS Online is a cloud-based GIS by Esri. There are two kinds of accounts - free, public accounts and organizational accounts. An account is necessary in order to save content. The ArcGIS Online Map Viewer is the place to create maps which can then be shared as is, as a viewer, a story map and much more. One big benefit for CT ECO users is that ArcGIS online allows you to add different map and image services to the same map, along with your own GIS data or services from other places. it's a real map mashup!
ArcGIS Online Map Viewer
The first step is to open the ArcGIS Online Map Viewer.
- Go to arcgis.com and sign in. If you do not have an account, you can create a free, public account public account.
- Click on Map to open a new, blank map the in the ArcGIS Online Map Viewer.
An alternative is open an existing map and save it to your account. Under this scenario, you are saving a copy of a map and can therefore make changes like adding or removing layers, changing the appearance and extent and sharing. It is a copy so you are not changing our original map (and cannot even if you tried).
The following instructions are specific to CT ECO services but apply to other services as well.
Add Services to the ArcGIS Online Web Map
Add Service to the Web Map from ArcGIS Online
If a service is part of ArcGIS Online and has the right key words, it can be found and added to any web map.
In the ArcGIS Online Map Viewer, click on Add and then Browse for Layers.
- Change from My content to ArcGIS Online.
- To add CT ECO services, type CT ECO or similar in the Search box.
- Scroll through the list of services and click +Add to add the desired service(s) to the web map. Note that with this method, only services can be added and not individual layers.
Add Service to the Web Map from Server URL
Using this method, a full map service which may include multiple layers, can be added to the web map. Alternatively, each layer of the map service can be added individually which opens up functionality in ArcGIS Online including changing symbology, reordering layers and more.
- In the ArcGIS Online Map Viewer, click on Add and choose Add Layer from URL. There are two ways to do this: (1) by clicking the drop down arrow next to the the Add button or (2) by clicking the + symbol at the upper left side of the screen.
- Copy/paste or type the URL into the box. For CT ECO, use one of the CT ECO server URLS
- https://cteco.uconn.edu/ctmaps/rest/services for map services (point, line and polygon based information)
- https://cteco.uconn.edu/ctraster/rest/services for image and elevation services
- Choose ArcGIS Server web service for the Type.
- Click the Browse For More Layers button
- Choose a layer (which is actually a service) from the drop-down list
- Choose Add Layer
Add Individual Layer from Service to the Web Map from Server URL
Functionality when added as an individual layer | Functionality when added as a service |
Layer is listed individually Can modify symbology
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Layer is listed within service group Cannot modify symbology |
Use the following steps to add an individual layer from a map service:
- Navigate to the server page for the layer. On CT ECO, that is either https://cteco.uconn.edu/ctmaps/rest/services or https://cteco.uconn.edu/ctraster/rest/services.
- Click on a folder and then a map service.
- On the MapServer page and find the Layers heading. Layers are numbered started with zero. Some services only have one layer.
- Click on the layer name. Notice that a number is placed at the end of the URL in the browser.
- Copy the link in the browser and be sure it includes the number at the end.
- Use the Add layer from URL option (described above) to add the layer to the map
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Image Services in ArcGIS Online
Image Services in ArcGIS Online: Display Settings
Image services can be manipulated in ArcGIS Online using the Styles tool located in the tool bar on the right of the screen. Change band combination and stretch type for an RBG image by selecting Styles and then Style Options.
For example, the color infrared (NIR) display is activated by changing the true color (RGB) to bands 4, 3, and 2.
Processing Templates
Many image services on CT ECO, especially elevation services, are published with processing templates. Processing templates contain a string of raster functions designed for the service. In the case of elevation, processing templates are usually aspect, hillshade, shaded relief, and slope that can be applied to the elevation service to change the way it is displayed. Processing templates do not change the underlying data.
If a service has one or more processing templates, the Processing Templates icon will be be on the right side of the map viewer in ArcGIS Online. Select it to see the list of available Processing Templates and click on one to apply it to the layer. Note that the image service can be added to the web map multiple times with a different processing template applied each time.
Image Collection Explorer
The Image collection explorer tool is useful to determine the names of the image tiles viewable on the screen. Toggle over the tile names with the cursor to highlight the tile on the screen.
Raster Functions and Tools
If the processing templates don't do the trick, other raster functions and tools might. They can be accessed by clicking the Analysis tab. For instance, NDVI can be calculated by using Raster Functions.
NOTE: Many raster functions and tools may use credits. The Estimate Credits tool at the bottom of the screen (above the option to run the function or tool) is useful estimate the amount of credits that will be used by running the function or tool.
Image Services in ArcGIS Online: Processing Templates
Many image services on CT ECO, especially elevation services, are published with processing templates. Processing templates contain a string of raster functions designed for the service. In the case of elevation, processing templates are usually aspect, hillshade, shaded relief, and slope that can be applied to the elevation service to change the way it is displayed. Processing templates do not change the underlying data.
If a service has one or more processing templates, the Processing Templates icon will be be on the right side of the map viewer in ArcGIS Online. Select it to see the list of available Processing Templates and click on one to apply it to the layer. Note that the image service can be added to the web map multiple times with a different processing template applied each time.
Image Services in ArcGIS Online: Image Collection Explorer
Image Collection Explorer
The Image collection explorer tool is useful to determine the names of the image tiles viewable on the screen. Toggle over the tile names with the cursor to highlight the tile on the screen.
Image Services in ArcGIS Online: Raster Functions and Tools
If the processing templates don't do the trick, other raster functions and tools might. They can be accessed by clicking the Analysis tab. For instance, NDVI can be calculated by using Raster Functions.
NOTE: Many raster functions and tools may use credits. The Estimate Credits tool at the bottom of the screen (above the option to run the function or tool) is useful estimate the amount of credits that will be used by running the function or tool.