Table of Content
The EarthAtlas (v.1) Web mapping application is being developed by the Water Systems Analysis Group (WSAG) at the University of New Hampshire. It is designed to allow a user to access and interact with a variety of data and model output for Earth system data layers related to water (natural and human) and any other information needed to our projects.
The EarthAtlas system is built with two major pieces:
EarthAtlas is a front end RIMS application (E-RIMS) serving its own full featured Web portal and a number of WSAG project-focused pages. These project-focused pages are specifically customized to meet the goals of each research project. The latter includes banner, styles, map views, mapping tools and functionality, dataset selection, etc.
The overall primary purpose and functionality of the EarthAtlas is dynamically (no preprocessing requited) displaying maps of
which are listed in the RIMS dataset metadata Database (DB) also called the Magic Table (MT). It contains information on dataset files location and structure, time series, units, projection, default styling, etc. So adding a new record (dataset) into MT immediately makes it searchable by the RIMS tools and available for RIMS WMS and WFS clients, e.g. EarthAtlas.
The informational overlays such as coastlines, country/administrative borders/labels, OSM and Bing street and satellite maps, etc. are served as geospatial reference only and, thus, not available for RIMS tools, e.g. data query, calculations, etc.
Basic navigation and view controls are those from the OpenLayers which include -
Each time map view changes with user zoom/pan/rotate actions or a new dataset gets loaded or modified (e.g. time series date, resample method, etc.) the new view gets recorded to the Map View History sequence, so that the user can navigate back and forth using history controls located in the upper right corner of the Map view -
Note, the Map View History gets reset, if map Projection changes.
Overview map control is located in the lower left corner of the Map view and it allows to see and drag/move the dashed rectangle of the present location of the view within the larger extent which is particular useful in high zoom levels (closeup views) -
Closed Overview Control
Opened Overview Control
Map attribution control is located in the lower right corner of the Map view and it allows to see ownership of the map tile server and the map information for the dataset presently being displayed. The attribution control can be opened or closed by the user at any time -
Map scale is located in the lower right corner of the Map view -
Coordinates of the mouse position on the map are displayed in the upper right corner of the Map view in decimal arc degree units of the Geographical projection -
Map projection choices and selector are located at the upper right corner of the Web page -
A user can switch map projection by clicking to the selector text box with the projection name (three projection choices are shown in the illustration above with current one highlighted) and the map with displayed data on it will be re-built for the closest spatial extent in the new chosen projection. Map view history and the dual layer tool will be reset though.
Raster and Vector Polygon Datasets are dynamically served by RIMS WMS based on their metadata stored in the RIMS DB that is also called the Magic Table (MT). Each dataset record in the MT contains information on the data file(s) location and structure, units and unit conversion on-the-fly, projection, map styling, map options, original source reference, download link, etc. The raster/polygon dataset that is displayed in the map view of the EarthAtlas is considered the Main Data Layer (MDL) and it retains focus of all RIMS tools, such as information table with the dataset title, legend, units, resample, dynamic styling, cell value query, time series graphing, etc. which is illustrated here -
There are three different ways to load Main Data Layer (MDL) to be displayed in the Map view area of the EarthAtlas using -
These methods are explained in the sections below.
Most relevant datasets for the project site that uses EarthAtlas Web engine are included to the pre-built dataset cascading menu here -
Presently WSAG metadata DB (Global MT) has over 26,000 active and about the same number of archived dataset records. It is impossible to add even a small fraction of those into the dataset menu described above. So, the EarthAtlas has a dataset search/query tool that can be called from clicking on “Dataset Search” tab for the Global MT in the Data Menu here -
The search can take one or two search strings or regular expressions with logical or/and conditions and any combination of four record fields to search, e.g. “Name”, “Data ID/Code”, etc. Search results indicate time series type (if any) and dates range. In addition it can also display “Status” (check for file existence” and “Extents” that are displayed in Geographical projection coordinates and grid cell size information. Example of search results is illustrated below -
Note, the search results in the blue font are actually links to display this dataset as the Main Data Layer in the Map view window.
The local metadata DB with a file path to it that is entered to the “Dataset DB” input field can be searched/queried using the same tool, but invoked by clicking “Search DB” button next to it -
If a user has the dataset ID, it can be used to load MDL to the EarthAtlas by adding it to the “Dataset ID” input form and clicking “Update Map” button as illustrated here -
This will load a dataset from the Global MT database. In case the dataset ID is from the local DB, the “Dataset DB” input form has to have a valid path to it -
A record of RIMS dataset metadata can be saved to an *.init file that has a nesting structure of Key => Value pairs with are quite similar to JSON format, but in Perl language. Loading such record into the EarthAtlas results has a similar action as reading it from the Global or local metadata DB. The metadata *.init file path has to be entered to the “Dataset ID” input form while leaving the “Dataset DB” input empty as shown below -
Two resample methods are available for mapping a given main data layer. While a Bilinear resampling makes gradual transition of map colors on the map and so avoiding “blockiness” of map views, it does not represent the actual values in the original data cells. Often a researched needs to see actual extents of each original data grid cell that is available with the Nearest Neighbour resampling method, e.g. for hurricane Irma over Florida on September 10, 2017 -
Bilinear resampling Nearest Neighbour resampling
The default resampling method for a given dataset is controlled by an entry in the dataset metadata, so if the user wants to keep his/her preferable method while loading other datasets, it can be preserved by checking “Lock” input checkbox next to the form of map resample method -.
The default color palette as well as data value range over the span of palette colors can be dynamically set by a user to have a better view of the data in certain situations, e.g. while viewing a close-up area on the map with a small variability of data values as compared to the variability in the Global view. Dynamic Styling Option has four input fields -
Note, non-default style stays retained for the next dataset displayed on the map. So, a user must explicitly Reset it in order to return to the default data styling.
Table of Color Palettes
The Dial Layer Tool allows to view two datasets simultaneously by changing transparency of the top layer. It can be opened by clicking the “Dual Layer Tool” button in the upper right corner of the area above map -
The Main Data Layer (MDL) is always the top layer, and the bottom layer is usually the previous layer that had been loaded to the Map view unless it is locked -
In addition to the option to lock bottom layer there are two more controls in the tool-
The i-Tool allows to retrieve a data value of the MDL over the map pixel of interest. It can be activated (and de-activated) by clicking on the i-Tool control in the upper right corner of the Map view -
When i-Tool gets activated, clicking on the map starts a data query of the MDL for the clicked pixel (see illustration above). The map Pixel Data Query popup indicates click point -
The Time Series Graph Window always displays data for the MDL dataset, if the latter is actually time series (excludes yearly climatology since those are one layer TS). The sequence of actions to build a time series graph for MDL pixel point is -
This is summarized in the illustration below -
The Time Series Graph Window has following options -
Clicking on the “United States” link brings up the graph of average annual temperatures for the US -
Note, There is an additional link in the “Polygon” in red font that displays a graph of average temperature for all countries combined.
The Time Series Control (TSC) is displayed in the upper left corner of the Map view, only if the MDL dataset is time series (TS) -
Folded TSC Unfolded TSC
The data of TS is displayed right above TSC - see circled date in the left illustration above. And the TSC starts in folded format (left illustration above) for the purpose of not obstructing the Map view. When unfolded, it has 3 sections -
The Date Chooser and Graph Data Dates sections of TSC are displayed for all TS types (temporal resolutions) except Yearly Climatology since it does not have dates to choose from.
Similarly to Raster layers described above, the Point datasets can be dynamically added to the EarthAtlas WFS from the Point metadata DB which we also call the Magic Table (MT). The metadata record in the DB for a given point dataset includes information about the data file location of data DB (MS Access, SQL, etc.), dataset title, project, credit reference, OL symbol style, etc. Adding or updating a new record in the DB makes it immediately available for mapping in the EarthAtlas.
A list of site select default point data datasets specific to each project can be added to the Map page initial loading. These are available for viewing as the map page starts. Loading addition point datasets at any time can be done using the same Search/Query Tool we had described for Raster datasets above. It opens from the menu above the Map view with the only difference that the “Point Data” radio button must be selected -
Search results show the dataset point symbol, name, and the number of points it contains. Clicking on the dataset name (in blue) opens it up on the Map view -
This loading option is essentially very much the same as for the Raster datasets described in this section above with the only difference that the “Point Data” checkbox has to be checked -
The Point Datasets Control (PDC) is located in the upper left corner of the Map view with the green shaded control expand button -
As you can see in the illustration above of the unfolded PDC, it has four columns -
Pointing the mouse over a site symbol displays a tooltip with the site Name -
And clicking on it opens the site Web page in a new browser tab. E.g. -
Presently the EarthAtlas offers a choice of 6 overlays with background transparency over the Main Data Layer (MDL) -
The first three are grouped and only one of them can be selected/used at a time -
Bing and OSM maps have opacity slider controls that get activated by clicking on the Bing or OSM blue links/buttons -
Note, clinking on the Bing blue link also offers a choice of aforementioned Road, Aerial, or Aerial with labels layers.
Other overlay choices include -
The checkbox selectors next to each overlay name are turning them on or off.
The data calculator is a powerful tool to perform a variety of algebraical, statistical, logical, etc. operations over a single or a number of single layer and/or time series gridded datasets. This tools can be activated by clicking on “The Map Data Calculator” bar just below the Map view -
Detailed instructions for using the Data Calculator are available in the link here -
Data Calculator Instructions
Questions and comments are welcome - email@example.com
Written by Alex Prusevich
Edited by Richard Lammers, Alexander Shiklomanov, and Stanley Glidden