Connecticut Imagery Viewer Help and Tips

Have a question? Email us at clear@uconn.edu and mention the Aerial Imagery Viewer.

Moving Around the Map | Layers | Coordinates | Overview Map | Compare with Swipe | Share

 

Moving Around the Map

Zoom

Zoom in and out of the map using the + and - tools located in the upper left hand part of the map.

To move around the map, click on the map and hold the left mouse button while dragging, then release the left mouse button. This pans the map to different areas, but does not change the zoom.

If you get "lost" on your map, use the home button to go back to the initial extent, which is the state of Connecticut.

 

Layers

Layer List

Layers IconViewer Layer ListThe layer list button in the upper right is one of the most useful buttons on the map. Click on it to see all the imagery datasets. 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 2016 Color Summer 0.6m is turned on (checked) along with the 2016 Infrared Summer 0.6m. Even though the Infrared Layer is turned on, it is not visible because the Color layer is covering it up. UNCHECK the Summer layer to see the Infrared layer underneath it.

Layer Names

The layer names are constructed by

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, it is looked 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 that is visible (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.

Layer Options

The dots to the right of each layer open a menu with some useful options including:

 

Zoom To - zooms to the extent of that layer.

Transparency - makes the layer see-through. It is a sliding scale from 0% (opaque, nothing showing through) to 100% (layer is completely transparent and therefore not visible). This is a handy way to compare images of the same location.

Move Up and Move Down: Changes the order of the layers in the Layer List which also changes the drawing order.

Description: links to the REST endpoint of that layer. You can read more detail about REST here, but this is where you can find some basic (and code-like) information about the layer, such as what server its coming from (look at the URL), the extent settings, attributes, pixel size, etc. Some layers include a detailed description, some do not.

 

Coordinates

The Viewer displays X,Y coordinates along the bottom. By default, the coordinates shown are the location of the mouse as you move it over the map.

Map Coordinates Tool

 

As long as the cursor icon is blue , clicking on the map drops a and returns the coordinates of that location.

To disable clicking on the map to get coordinates, click on the cursor icon so it is white instead of blue.

 

Overview Map

To view an overview map, click on the arrow in the lower right corner of the viewer. Once the overview map is open, click to maximize the overview map or the arrow to close it.

 

Swipe

Compare with the Swipe Tool

The swipe tool is a nifty way to compare layers in a map. To activate it, click the swipe icon in the lower left corner of the viewer Swipe tool. A slider opens as well as a menu. By default, the swipe will peel away the 2016 Color Summer 0.6m layer and show the next set up imagery that is turned on underneath it. You can change what is visible with the swipe. First, be sure the desired layers are checked on in the layer list. Next, use the swipe dialogue to choose the layer to swipe, or peel away. Cool!

To turn OFF, or hide, the swipe, click the icon Swipe tool again.

 

 

 

Share

The share icon is in the upper right-hand corner of the viewer. Clicking it opens the share panel which contains a link to the map as well as shortcuts to share it via email, facebook, twitter and google plus and code for embedding in a website. The Link Options provides choices as to what is included in the link (the URL parameter) which determines what happens when someone else uses the link.