ArcGIS is optimized to work with imagery and raster data. You can work with satellite and aerial imagery , or raster datasets representing GIS layers, gravitational models, or a DEM. You can adjust the appearance of imagery to enhance specific features or merge an image with a hillshade. You can use imagery as a background (basemap) to enhance the assessment and presentation of other data. You can also perform advanced analysis, such as finding areas of change, image classification, weighted overlays, deriving watersheds, and much more.
The Catalog window makes it easy to select and view imagery and raster data by providing unique icons.
ArcGIS makes working with imagery easy through the use of the raster product. Raster products are raster datasets from well-known sensors that incorporate the associated metadata to simplify working with them. These are standard products that can be computed on the fly from sensors like Landsat or QuickBird. The application combines the bands to create one of several products, which makes it easier for you to add that data to your map display. For example, Landsat 7 data appears with this raster product icon and, when expanded, allows you to choose a particular band combination or a pan sharpened image to add to your display.
ArcMap has optimized imagery display so that adding imagery and raster data is seamless. Navigate to the data in the Catalog window, then drag and drop it onto the display view in ArcMap. ArcMap will read the metadata to optimally display your image.
Once added, ArcMap will automatically optimize the display of each raster dataset using display parameters such as renderer type, stretch type, gamma, and contrast based on the metadata. Whatever type of data you are working with, ArcMas has a solution, whether it's a single band dataset, multiband dataset, or data with a pre-existing colormap. ArcMap can read wavelength information in the metadata to display a natural color band combination. When working with imagery from well-known sensors, a raster product is created, renaming the bands, and simplifying your workflow. Mosaic datasets allow you to view the multiple layers that compose the datasets, and raster catalogs with more than nine images are displayed as a wireframe delineating the boundary of each image to give context to where you are working.
The Searchwindow capabilities have been extended in ArcGIS 10.2 to use the key properties of raster products and mosaic datasets to quickly locate your imagery. Search will extract metadata from imagery within a mosaic dataset. Once indexed, you can easily locate imagery from the sensor you want, covering the location you're interested in with the attributes you need, such as minimal cloud cover. From the search results you can add imagery directly to the desktop or into a mosaic dataset.
There are many tools in the Image Analysis window to help you improve the appearance of your image by altering histogram stretching. Use sliders to adjust the contrast , brightness , and gamma of the image. The Interactive Histogram Stretch button is useful to help you understand the distribution of pixel values for image rendering.
ArcGIS provides tools to help you analyze raster data. The Pixel Inspector tool is used to view an area of pixel values in your raster dataset. The Swipe Layer tool is used to interactively reveal layers beneath the layer being swiped. To learn about these tools and others, see the following:
Use the Identify tool to get pixel value information for a single pixel. Use the Get Cell Value tool when you're working in a geoprocessing model.
The Image Analysis window provides access to both processing and display capabilities for raster data and imagery. You can easily display a DEM as a shaded relief and modify the color ramp. There is also a tool to calculate the difference so you can see changes between datasets. Plus, you can mosaic multiple rasters into one .
One special capability of the Image Analysis window is adding functions to the raster layers. You can modify these functions and perform more advanced analysis on your raster data. Many of the buttons in the Processing section of the window insert functions into the layer. There is also an Add Function button to give you access to the function chain so you can pick the processing functions you want to apply and chain them together to create more complex analyses. These functions are applied as you access the data and are saved within the layer files, making them quick to display and easy to share.
The Image Analysis window contains a set of mensuration tools, including tools to measure point, distance, angle, height, perimeter, and area from an image (raster dataset or mosaic dataset) with sensor information (geodata transformation).
Mensuration applies geometric rules to find the length of lines, area of surfaces, and volumes using the information obtained from lines and angles in your scene. It can also use information in the metadata to measure the height of features based on their shadows and determine the absolute location of a feature as well.
There are many ways to leverage your raster data in analysis operations. In most scenarios, you will be performing operations that manipulate cell values. There are many tools in ArcGIS for Desktop that enable you to work with raster data for data management, conversion, and transformation; however, to utilize raster data within an analysis operation, you will need one of the extensions.
There are ArcGIS extensions that perform analysis on your raster data.
You can use tools from these extensions and connect them together to create models to help automate your workflows.