A Guide to the Layout and Design of Iris
Explore the buttons and features in Iris to visualize and analyze GDS data. Follow along for a quick tour of the software's basic navigation.
Getting Started
Iris is a cloud-based software that can be accessed through any web browser, including Google Chrome, Microsoft Edge, and Apple's Safari. To use Iris, navigate to: https://app.descarteslabs.com/iris/
If prompted, please enter your Descartes Labs login credentials. Should you encounter any difficulties accessing Iris, do not hesitate to reach out to support@descarteslabs.com.
Upon successful login, you will be greeted with the default view in Iris, ready to import your data and begin your analysis.
Data and Analysis Panel
Within the left-hand panel, you'll find a variety of tools and features designed to help you easily add, adjust, analyze, and export your data. Let's explore these elements in a step-by-step manner.
Deformation layers
The section on deformation layers in the data and analysis panel serves as the main control for the data displayed in Iris.
To add data to the session, simply click on the "+" symbol. You will then be presented with a list of available sites for viewing, including some demonstration analyses.
In this section, the Round Mountain mine site example will be selected from the Demo Products list. Upon selection, a precise analysis window can be chosen to add to the scene, with the most recent one being selected by default. Additionally, metadata relevant to this specific site will be displayed on this page. Once the analysis has been determined, simply click on 'add layer'.
By default, when you open the map window, you will see Line of Sight (LOS) results as the default data layer. LOS results show the movement of each point towards or away from the satellite in millimeters over the observation period. If the analysis includes data from both ascending and descending satellite passes, the default layer will be Up(+)/Down(-), which displays the vertical movement of each point. The data layer can be changed in the drop down menu. Details on each data layer are explained in this article.
The remaining settings in the Deformation Layers section allow for adjustments to the visualization of data in the map window. Users can customize the minimum and maximum values for the linear histogram stretch of the data, as well as apply a masking threshold to filter out points with movement below a specified value. For instance, inputting a value of 10 in the Mask Threshold box will eliminate points with less than a 10mm movement, whether positive or negative, during the analysis period. The time slider tool enables users to track the evolution of deformation over time by stepping back through the analysis.
Processing toolbox
The processing toolbox contains settings and tools designed to extract insights from your InSAR results. These tools are currently focused on anomaly detection, with ongoing development of new tools and features.
Please note that the visibility of certain tools may vary based on your Iris subscription level.
Stack analysis: This tool is only available with a Quicklook subscription. This tool allows enables users to view burst footprints from Sentinel-1 and calculate deformation results anywhere in the world, on demand. See this Quicklook article for more details on this powerful tool.
Alerts: A series of checkboxes allow you to calculate and display alerts from the most recent data collection, as well as display historical alert data for additional insight. A detailed explanation of the anomaly detection tools are provided in a dedicated article here.
Optical Imagery: Users with access to Descartes Labs' Standard or Premium Data packages will be able to display additional raster images here, including Airbus SPOT imagery, NAIP, or Sentinel-2. Additionally, if clients provide proprietary imagery such as drone imagery or lidar data, it can be visualized through this menu
Derived layers: A series of calculated raster datasets are available through this menu including digital elevation models (Copernicus DEM, NASA DEM, and SRTM) as well as slope and aspect layers calculated from the SRTM dataset. Additionally, Descartes Labs' proprietary Global Velocity Layer, which shows annual deformation data over large areas can be added to the scene.
Vector layers
Vector layers can be used in a number of ways in Iris. Polylines and polygons can be added or drawn within the map window to calculate and visualize deformation over a transect or averaged within an area. Iris currently supports uploading of .geojson files in latitude-longitude coordinate system.
To draw a vector layer, click the "+" icon next to Vector layers and select between drawing a Polygon, Polyline, or Point.
Drawing Vectors
To draw a vector, click the pencil icon next to your newly created vector layer's name to make the layer editable. Next, click the draw vector icon that will appear on the left side of the map window. This icon will be slightly different, depending on if you chose a polygon, polyline, or point vector layer.
To draw your shape, simply click the map to add a node and continue clicking until you are ready to finish. To complete a polygon, click the first point again to finish your shape. To complete a polyline, click the last point in your line again to stop drawing.
If you are finished, click the pencil icon again to make the layer no longer editable. Note however, the area and transect plotting tools will only work properly with either a single polygon or polyline within each respective layer.
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Inclusion and Exclusion Polygons
Polygon vectors can also be used as inclusion or exclusion vectors that can change the area used in each GDS analysis. This feature will be covered in a separate article and will typically be done in coordination with Descartes Labs support.
Export layer
If you would like to work with data from an analysis in an external software, the results can be downloaded directly from Iris. In the Export Layer section, click the Save Icon to view an export menu and select download analysis. The resulting prompt will provide a download link to the specific analysis you have requested.
Data downloads are provided parquet file format. Parquet is a relatively new open sourc, data format that stores large vector databases much more efficiently than other vector file formats such as .shp, .tab, or even .geojson files. All .parquet files will be provided in WGS84 Latitude-Longitude (EPSG:4326) format and can be read by most modern GIS software packages, like ArcGIS and QGIS. There is currently a known issue with .parquet files in QGIS for Mac, but a workaround is available, please reach out if you have any issues.
Navigation Bar
The Navigation Bar in Iris has a number of features to help you control the map window. This includes Bookmarks, Basemaps, zoom, and geographic coordinates.
Bookmarks and Location
The Bookmarks dropdown allows you to save the location of the map window so you can quickly jump to it later. This stores not only the center coordinate of your view, but also the zoom level. Click Create Bookmark to save your current view with a name of your choice. An interface to manage your saved bookmarks is also available under this dropdown.
To navigate to a specific location, enter the latitude and longitude (WGS84) coordinates in the box on the right hand side, separated by a column. Coordinates can be copied directly from Google Maps by right clicking the
Basemaps
A number of free open-source base maps are available to help you interpret your data. Similar to programs like Google Maps, you can toggle between both a streetview and satellite view provided by OpenStreet maps. Additionally, you will find a topographic map, shaded relief map, and open source geologic maps provided by Macrostrat. Finally, for a simple view of your data, a light (white) and dark (black) background are available.
Map Window
The map window is your main way to visualize data. It displays the points from your GDS analysis, results from anomaly detection, and vectors layers. It also shows a scale bar and the legends that correspond to your GDS data layer and anomaly layers to help with your interpretation.
Navigation of the map window is intuitive and similar to other mapping programs. Left click to pan around the map window and control zoom using your mouses scroll wheel or the "+" or "-" icons in the upper left. There is also the option to maximize the map window to full screen mode.
The map window also hosts the green deformation pointer icon that corresponds to the data that is displayed in the deformation time series window when point measurement mode is selected. To view the deformation associated with an individual point, simply drag the green icon to the point of interest and the deformation time series plot will update automatically.
Deformation Plot and Controls
The deformation plot shows a graphical display of your GDS data. This plot functions either as a time-series, when working with point or area data, or as a sectional view when visualizing a transect. Above the plot, you will have controls that let you toggle between the measurement modes, select the vectors used for areas and transects, lock the Y-axis, and display standard deviation error bars on data layers where applicable.
Time-series plot
When the measurement mode is either Point or Area, the Deformation Plot will behave as a time-series viewer, with Time shown on the X-axis and the data from the selected Data Layer (e.g., LOS) on the Y-axis. In point mode, the plot will show the measurements that correspond to the green pointer icon on the map. This plot will update live as you drag the point within the Map Window. In Area measurement mode, the plot will show the average deformation within the polygon vector that is defined in the drop down on the right.
The points on the deformation plot in time-series mode represent the deformation present at each time epoch within the analysis window from left to right, with the leftmost point representing epoch 0 and always being a value of 0. In both Point and Area mode, modifying the time slider to in the Data and Analysis Panel will not affect the data displayed on the plot.
Transect plot
If the measurement mode is switched to Transect mode and a suitable polyline vector is selected, the deformation plot will switch to a cross-section plot. In this view, the X-axis shows distance in meters along the polyline while the Y-axis shows the corresponding deformation at each point that the line intersects. As you over your mouse over the plot, a corresponding symbol will appear on the polyline in the map window to show the location of the measurement.
In the cross-section plot, the deformation data displayed will correspond to the date of the epoch selected in the time slider control in the Deformation Layers section on the left. By moving through the time slider, the plot will update and show how deformation has progressed through the analysis period. It can be very helpful to check the Lock Y-Axis feature on the last epoch before in order to keep a consistent scale for comparison as you move through the analysis dates.
