Zoom In and Out

Zoom in and out of the map using the + and - tools located in the upper left corner of the map. Alternatively, use the scroll wheel on your mouse.

To pan around the map, left-click on the map and hold the left mouse button while dragging. The cursor will turn into hand while the pan is active. If you get "lost" on your map and need to go back to the big picture, use the Default View  () button in the upper left.

Previous Extent, Next Extent

If you have zoomed at least once since the viewer was opened, the Previous extent arrow will take you back to the previous zoom area. The Previous extent button can be used multiple times. After using the Previous extent button to go back, the Next extent takes you incrementally forward through already viewed extents.

Basemaps

A Basemap draws below the other layers in a map. To change the basemap, click on the Basemap Gallery icon. Choose from a long list of options. Don't know what to choose? Try the Imagery Hybrid, Topographic, or the Dark or Light Gray Canvas.

TIP!  Although not technically listed under the basemap button, any of the Elevation or Imagery layers can be turned on in the Layer List and function as a basemap.

Overview Map

The Overview Map icon is a tiny arrow in the lower right corner of the viewer. Click  to open and show the map and click  to close it.

Layer List

In the Aerial Imagery Viewer, the Layer List is open by default on the right side of the viewer when using a large screen device. The Layer List icon () can be selected when using a tablet or mobile device. The layers form a stack (bottom of the list draws on the bottom of the stack) and each layer can be turned on and off. A check mark () means the layer is turned "on" or visible (as long as no other layer higher on the list is turned on and is hiding it from view). In the graphic to the right, notice that the 2023 Color Spring 3inch is turned on (checked) along with the 2019 Color Spring 3inch. Even though the 2019 Layer is turned on, it is not visible because the Color layer is covering it up. UNCHECK the 2023 layer to see the 2019 underneath it.

Layer Names

The layer names are constructed using the following format

year of acquisition + bands displayed + season of capture + pixel resolution

• Year of acquisition: The year that the airplane flew with a sensor and took the picture.
• Bands displayed: Based on the sensor or camera used, imagery is captured with 1 or more bands. A black and white (B&W) image has only one band and is displayed in grayscale. A color image is displayed using red, green, and blue bands which is what we are used to seeing with our eyes. In some cases a fourth band, near-infrared, is captured. The infrared band provides reflectance and other information that we cannot see with our own eyes. When an image is displayed as infrared on the computer, it is looking at near-infrared, red, and green light. In these images, healthy green vegetation is bright red/pink.
• Season of capture: Imagery is usually captured in the spring between snow melt and leaf out or in the heart of the summer. Spring imagery allows ground features to be seen before leaves and plants cover them up. Summer imagery is useful or assessing things that grow such as crops and trees.
• Pixel resolution: Digital images are made of pixels, or picture elements. The size of the pixel helps determine the detail that is visible in the image. The smaller the pixel, the more detail (and the larger the file size). A 1 meter pixel means that each square pixel of the image covers one square meter on the ground. Imagery available here ranges from 1 meter to 3 inch pixels.

Some non-imagery layers are listed in Groups. Click on the  to open a group. The group needs to be checked in order for layers inside it to be visible .

In this example, the Town Group is checked on as well as the Town Line  layer inside the group. The other layer is not visible on the map.

Expand as many groups as you like and turn on () any combination of layers. Remember that layers draw in order. Layers higher up on the list will draw above and on top of layers below. Layers often overlap so may cover each other up. If this is the case, use transparency or turn layers off.

Reorder Layers

The order of layers in the Aerial Imagery Viewer can be changed. Locate the 6-dot reposition () symbol next to a layer. The mouse turns to a cross-hair indicating that clicking and dragging the layer will move it to a different spot higher or lower on the list. Layers can be moved outside of their home group and/or into a different group.

Remember that layers draw in order. Layers higher up on the list will draw above and on top of layers below. Layers often overlap so may cover each other up. If this is the case, use transparency or turn the layer off.

Options

Each group item and layer has three-dots on the far right which opens the Options menu.

Some layers types have more options than others.

TIP! The Options menu is not accessible (it is grayed out) if the layer is not visible (be sure the layer AND the group are both checked).

Transparency makes a layer partially or fully see-through.

It is important to be familiar with the layers before using them for a particular application. Some layer information may be accessed using the Options icon () next to the layer name in the Layer List and then clicking Details. More detailed information, including guides and metadata, can be accessed through the CT Aerial Imagery page.

The Legend is automatically displayed to the right of the map next to the Layers List tab when using a large screen device. Click the tab to view the legend, which will include the symbology for the layers that are visible (checked on) in the map. The legend will be most helpful for the non-imagery layers, such as the CT Base Map group.

You can access the Legend using the icon () when using the Aerial Imagery Viewer on tablets or mobile devices.

To Collapse or Close the Legend on tablets or mobile devices, click on the double arrow or X on the right of the panel title.

Symbology, or the symbols used for a layer (which are also shown in the legend), can also be viewed in the Layers List. Click on the Legend icon () to the right of the layer name to show the legend.

TIP! Selecting the Legend icon for a group will show the legend for all active (checked on) layers of the group.

TIP! To turn off the legend so that it is no longer visible, click the Legend icon again.

Clicking on the map at any location opens a pop-up that contains information for any layer that is visible AND has a feature at that location. If more than one layer has a feature at that spot, use the Previous and Next arrows in the upper left or lower left depending on the box location to to flip through the features. The upper or lower right corner shows how many features are at that location and the Select feature icon lists them.

The information in the pop-up comes from the layer's attribute table. Try clicking on different features on the map and notice how the information in the pop-up changes. To view the full table record for any feature, choose the Actions icon () and then View in table.

Zoom to changes the map extent to center on all features that are at that location. It can be a big or small area depending on the size of the polygons included.

TIP! Raster layers, which are the ones made of pixels, behave differently in a pop-up than vector layers, which are the ones made of lines, points, and polygons.

Location Search  

Use the Search Tool (upper left) to find a location, place, address and more. Type into the Search window and press Enter. Search Results will appear in the side panel. Click on the result you wish to navigate to. The map will redraw with the feature centered on the map. Click the in the  to remove the search results.

Find My Location

The Find my location button adds your current location to the map and zooms to it. The blue dot is your location. Note that the location could be influenced by the internet provider and/or the accuracy of the basemap. It also requires location to be enabled on your device.

Measure

Select the Measure icon and then choose to measure distance () or measure area (). Once a measure tool is selected, the mouse turns to an orange circle.

Click on the map to start the measure. Notice that the orange and white line or orange fill is measuring as the mouse moves. Click again to add vertices and continue until the line or shape is complete. Double-click to finish. The measurement is shown on the map and in the Measurement window. The units can be changed at any time.

TIP! While in the middle of measuring you can makes changes like to the measurement units, turn layers on and off, move the measurement window, and more.

Scale Bar

The scale bar is in the lower left corner of the map.

Coordinates

The coordinates tool reveals the coordinates as the mouse moves around the map and for a selected point. To select a point use the Enable clicking the map to get coordinates () icon on the left and click on the map. The coordinates at that location are shown. Use the Select the output coordinate system drop-down to change the coordinate system. Use the copy icon to copy the coordinates to paste elsewhere.

Coordinate Conversion

The Coordinate Conversion tool uses input coordinates in one coordinate system and provides output coordinates in a different coordinate system. One useful capability is finding an address from a map location or the opposite, finding a map (coordinate) location from an address.

First, select the starting location by typing in a known address or using the Add Point icon ().  The equivalent coordinates automatically populate in the Coordinate Conversion panel.

The coordinate systems are as follows:

• Address
• DD - Decimal degrees
• DDM - Degrees decimal minutes
• DMS - Degrees, minutes, seconds
• Long-Lat - Longitude and Latitude
• MGRS - Military Grid Reference System
• USNG - United States National Grid
• UTM - Universal Transverse Mercator

TIP! Look for the copy icon () throughout the tool to copy the coordinates for pasting elsewhere, like a document or email.

Compare with the Swipe Tool

The Swipe tool is a nifty way to compare layers in a map and is activated by selecting the icon to the left of the screen. Once activated, a menu appears:

Be sure that the switch in the upper right corner of the menu box is flipped to activate the tool (). There are options to choose a leading layer (the layer that display on top) and a trailing layer (the layer that will display on the bottom while the leading layer is being swiped over it). In the below example, the 2023 Color Spring 3inch was selected as the leading layer and the 2023 Infrared Summer 0.3m was selected as the trailing layer.

Note: Only active layers (layers that are checked on in the Layers List) can be selected as a leading or trailing layer. Inactive layers will be grayed out in the Swipe tool menu.

Turn off the Swipe tool by clicking the switch in the upper right corner of the menu box (it will turn white instead of blue).