Manipulation Examples

Load Data Layer from Catalog

To visualize, analyze and/disseminate the any data layer, the user has to load the data first. To load a data layer from catalog, click the icon to invoke the function "Catalog". A pop-up window will show as follows:

The pop-up window has the most recently available SMAP 9km top soil moisture data layer loaded as the default data layer. For example, to load a NASS categoric top soil moisture condition data layer assessed from SMAP 9km top soil moisture data, use the input options as shown in the following catalog pop-up window. The loaded data layer is illustrated as the following figure on the right:

View All Data Layers Loaded from Catalog

To view all the data layers loaded, click the icon . The following figure lists all data layers loaded from the Catelogue on the left panel. The loaded data layers can be turned on/off for visibility by clicking icon . The default setting for every loaded layer is visible. To remove a loaded data layer, the user just needs to left click the icon next to the data layer. The user can move a loaded layer up or down. To move a loaded layer up or down, place the mouse cursor over it, press and hold down the left mouse button, then move the mouse to the position you want while still holding down the left mouse button.

Apply Crop Mask to Illustrate Map of Cropland and Add Auxiliary Layers

To illustrate a map of the cropland, user can apply the Crop Mask data layer from Auxiliary Layers. Click the auxiliary map layer icon . Locate the Crop Mask Layer and click the visibility toggle icon to make the layer visible. The Crop Mask Layer will be overlaid on the loaded top data layer as shown in the following figure.

Similarly, to add any other auxiliary data layer, click the auxiliary map layer icon and click the visibility toggle icon of the auxiliary data layer you want to overlay on the loaded top data layer.

Get Pixel Information

To query and display data type and data value of a selected pixel, click the icon to invoke the function "Pixel Info". Move the mouse pointer to a pixel of interest and left click the mouse. The data type and value of the top layer will be displayed as follows (NDVI is the top layer in this example).

Each pixel within a data layer has a category name, category value, and a defined color. The color and category name information can also be found in the Legend.

Define An Area of Interest

In order to perform any zonal statistical analysis, it is necessary to first define an Area of Interest (AOI). There are four ways to select an AOI.

By State/County Administrative Boundary

You can select an AOI by state or by county within a state. You can only select one county within one state at a time. Clicking the tool icon to select a specific state, county, Agricultural Statistics District (ASD) or Region as an area of interest, a pop-up window will show as follows:

After selecting Iowa, Calhoun County, the selected area of interest (Calhoun County, Iowa) will be highlighted.

By Rectangle

Click the icon first to invoke the function. Then click the mouse at the top left corner and lower right corner to define rectangular area of interest as shown in below. Click the icon again to disable the rectangle AOI drawing function.

By Polygon

Click the icon to invoke the Polygon Area of Interest function. To define a polygon area of interest, the user can click around the polygon boundary of interest. Double click the last vertex of the polygon to finish drawing the AOI as shown below. Click the icon again to deactivate this function.

By Imported AOI

The AOIs can be existing server-stored administrative boundaries, such as state or county boundaries, and AOIs drawn using the tools provided in this application. In addition, this application also allows users to upload their existing customized AOIs to conduct analysis in this application. To upload the customized AOI, the user needs to click the icon to import a vector file (in GML or ESRI Shapefile format) to define the area of interest as shown in the following pop-up windows:

Click the "Browse" to locate your customized AOI file. Another dialog windows will pop-up as below.

Select the customized AOI ZIP file "AOI_test.zip" and then click the "Open" button. This dialog window will disappear. The AOI file named "AOI_test.zip" will appear in the import function window. Clicking the "Upload" button will import the user's AOI as shown in the following figure.

*Note: To upload an ESRI Shapefile, you must compress all files in a single .ZIP file. The ZIP file must include at least the following four files: .SHP, .SHX, .DBF, and .PRJ.

**Note: You can drag & drop GML files directly on the map.

Perform zonal statistics for an Area of Interest

Before starting any statistics analysis, the user needs to load the data layer of interest into the application by clicking the Catalog icon . To perform zonal statistics, an area of interest (AOI) needs to be pre-defined. With the AOI defined, click the Statistics icon , and the function will calculate the statistics within the AOI for the currently loaded top data layer. It will pop-up a window, which presents a table of pixel counts and acreage calculated from the pixel count of every category within the AOI.

For example, as shown on the left figure below the daily NDVI data on April 26, 2020 was selected from the catalog. On the right figure below, the State of Iowa was selected as an AOI.

The following pop-up windows are the results of clicking the Statistics function icon. The upper table below summarizes the statistics of the entire State of Iowa daily NDVI on April 26, 2020. The lower table below shows the statistics of the NDVI of the cropland of the State of Iowa on April 26, 1. The cropland only statistics can be calculated by check the "Cropland only" check box right below the tool bar of the statistics summary window. In the table, the NDVI values are divided into 11 segments for better visualization. This NDVI data segmentation is the exact same setting as the NDVI thematic mapping.

\ The toolbar at the top of the window, contains five functions for statistics data presentation and dissemination. For better dissemination, the statistics data can be viewed and copied from a simple txt format with the view table function , printed on paper with printing function, and exported to an electronically readable file in .csv format with the export function .

For graphically visual representation of the statistics results, either Pie Chart or Bar Chart presentation can be automatically generated by clicking icon  or as shown below.

Create PDF Map

To create a PDF formatted map of a specifically predefined AOI of the currently loaded top data layer, the function Create PDF can be used. Clicking the icon , the following panel will pop-up.

User may input the map title (or use the default title), select the printer/plotter paper size, and select the overlaid boundary and then click the red submit button. A predesigned PDF map will be automatically created as shown in the figure below.

Analyze Changes

This application currently implements two data change analysis tools: Swipe function and Profile function. Both tools are located on the left toolbar.

Swipe

Swipe function is implemented for comparing two different data map layers in detail. Clicking icon , a swipe control bar will pop-up as follows:

First, click the icon and a data layer selecting window pops-up. Select the data layer as shown on the left figure below. The red becomes green indicating the data selected. Similarly, click the icon and a data layer selecting window pops-up. Select the data layer as shown on the right figure below.

This example illustrates using Swipe function to compare two SMAP 9km top and sub categorical soil moisture condition layers on different dates. By dragging the green sliding bar to the left or right, you will see one layer swiped on top of the other data layer. The difference between two map layers is clearly illustrated at the overlapping line, as circled in red in the States of Wyoming, Colorado and New Mexico in figure below.

Profile

This function profiles the daily or weekly NDVI, and 9km SMAP top and sub soil moisture of a selected pixel location.  To generate a profile of a point of interest (POI) on the data layer, user needs to left click the Point tool on AOI toolbar and then move the cursor to a point of interest and left click the mouse. A selected POI is shown as following:

To generate a profile of an interested data layer, click the Profile icon and a pop-up dialog window for selecting data layer for profiling will show up. User can then choose a data layer of interest as shown on the left figure below. Click the "Submit" button after selecting the data layer of interest. A profile of the selected data layer at the POI will be plotted as shown in the right figure below. For 9km soil moisture data, both average and maximum data will be plotted as shown the figure.

Composite

The composite function provides a tool for user to assess the soil moisture condition using latest available data in the current period with an option to include partial previous week data. To conduct an ad-hoc composite data layer, user needs to click the composite function icon first. A dialog window will pop-up. User needs to select a data type from three original daily soil moisture data products and select a set of different dates as shown in the following dialog window.

After selecting the data type and dates of the layers to be composited, user needs to select a composite method and click "Calculate" button. In this example, we use the default method "AVG"- "Average", which will take the average value of all selected layers. The other available method is "MAX", which takes the maximum value among all layers. The composited data layer will be added to the loaded Layers as a "top" layer, Composite Layer, as shown the following screen capture:

User can perform normal operations including Statistics, PDF Map, and Download.

Download

The download function icon is located at the lower end of the left toolbar. Downloading the defined area of interest of the top layer data can be performed by clicking this download icon . A dialog window will pop-up as shown below. Edit the output file name and click the "Save" button to save the file.

One-Click Report

This function enables the application to produce statistics report of the top data layer for five regions in California: Central Valley, Coastal, Desert, Mountain Coast, and Sierra Nevada. User needs to decide which data layer to report and click the Layers icon to move the data layer you are interested in to the top. If the data layer has not been loaded yet, click the Catalog to load the data layer you are interested, such as SMAP Top-Categorical, weekly data as shown in the following figures.

With the data of interest loaded, clicking the icon will pop-up a dialog window, which displays the statistics results, charts and a PDF map of the default Central Valley Region for visualization. Clicking the "Generate Report" Button will generate the statistics report in text and maps in PDF for five individual California Regions, including Central Valley, Coastal, Desert, Mountain Coast, and Sierra Nevada.

Once it the report is generated, a dialog window will pop-up for the user to enter the name of the output report name as follow.

After entering the file name, click the "Save" button to save the report. The saved file will be compressed. The user can extract the file for further compiling and editing.

Animation

The animation function enables the user to render a series of frames of maps (images) of a given period at a selected speed. It enables users to illustrate the change dynamics of the selected data layer of interest spatially and temporally. The animation function takes the currently loaded top data layer as the default data type. To animate a period of a specific type of data layer of interest, user needs to load the type of data first by clicking the Catalog icon . In this example, we load the SMAP top soil moisture 9km Anomaly data for animation as shown below:

Next, we need to set the period of the time series for animation. The Click this button to invoke the animation function. An animation control bar will pop-up as shown below:

The app's animation period defaults to the most recent available 30 days as shown on the calendar on the right side of the animation toolbar. If the default period does not meet your needs, the user needs to set his/her animation period by clicking the start and ending calendars on the animation bar. The starting and ending dates of this example are set to April 1, 2020 and May 15, 2020 as shown in the following figure:

After setting the animation period, click the play button to load and play the data. Once the "Play" button is clicked, the "Pause" button appears. (The "Play" button and the "Pause" button toggle each other.) The animation play is defaulted to repeat. User can use the "Repeat Control" toggle button on the animation bar to turn the "Repeat" on or off. To adjust the play speed, stop the animation player and slide the green speed button to right to increase the play speed or to left to reduce the speed.