MOHID Studio uses a customized Geographical Information System (GIS) to display dynamic maps. Information which can be displayed includes raster images and vector data. All data is presented in form of layers.
Raster images are typically used to add a background to the image. These can be added from local images or from Web Map Servers (WMS).
MOHID Studio supports different kinds of vector data sources. Special emphasis is given to data related to MOHID models: (i) special ASCII (and XML) files in MOHID format and (ii) model results stored in HDF Files. Other vector data sources can also be added, including ESRI Shapefiles and HGT files. Vector data can be displayed in several different ways, using simple styles or theme based styles. MOHID Studio also supports time animated vector data.
Tasks related to the map visualization can be performed from the "Map" menu (represented on Figure 1).
Layers are displayed in the "Map" window (Figure 2). This window is divided into two main areas: (i) the list of Layers (Layers List), on the left side of the window, and (ii) the Map Display, on the right side of the window.
The list of Layers shows the currently loaded layers of the map. At the bottom of Layers List is located a small tool box which allows to control the current display time (in the case time animations are loaded). The Date & Time control is further explained below.
The Map Display shows the maps based on the currently loaded layers. A small set of tools, located in the upper right corner of the Map Display (represented on Figure 3), allows panning, zooming and querying the map. At the right side of the Map Display appears the legend of the currently loaded layers (see Figure 2).
Some functions which can be accessed from the "Map" menu can also be accessed from the context accessible from the Layers List (Figure 4).
The Date & Time control allows to change the date and time of visualization, displaying the results on the Map window. When pressing "play" (see Figure 5) the results from the simulation will be played and will be displayed as an animation on the Map window.
The start time and end time can be changed as well as the step between displayed times. To change these settings press on the green clock (the button on the right of Date & Time control – see Figure 5). The time displayed can be changed in the Current Time window as shown on the Figure 6.
Start time, End time and the Step configure how the Date & Time Control will behave. By adding a new layer, these values are automatically updated.
Maximum Offset (Max. Offset, on Figure 6) is the time span which is used to look for data inside time based layers (HDF Files). The GIS engine will only display data sets which instant is greater than the current display time less the maximum offset and lower than the current display time plus the maximum offset.
The time step is the time the application waits before displaying the next frame, after pressing the "Play" button.
Layers loaded into MOHID Studio’s GIS have common properties: (i) if they are to be displayed (enabled/disabled), (ii) minimum/maximum zoom visible, and (iii) layer name.
Enabled layers are displayed in the map on top of each other, considering the same order as shown in the Layers Lists (the top layer in the Layers List is the topmost layer in the Map Display). Layers can be moved, up and down, through the context menu or through the buttons "Move up" or "Move Down" in group the Manage Layers from Map menu (see Figure 1). Layers can be enabled / disabled by checking / unchecking the box in the "Visible" column in the Layers List.
The properties of a layer can be accessed by: (i) double clicking over it on the Layers List, (ii) selecting "Properties" from context menu of the Layers List or (iii) by pressing F4.
Raster layers are mainly used to display some background in the map. MOHID Studio supports two main types of raster layers: (i) raster collections from georeferenced images and (ii) raster images from WMS server.
Raster Collection are a set of georeferenced raster images which are stored on your computer. These images can be added by pressing the button "Local Raster" on the Background group from the Map menu (see Figure 1). A window like the one represented in Figure 7 will appear to configure the Raster Collection. Here it is possible to add or remove individual images to the raster collection.
Individual raster images must be georeferenced. This means that these images are either images which contain information about their georeference (example: GeoTiff) or that there is an additional file which contains the georeference information (ESRI world file - *.jpw).
For large raster collections, and for raster collection with different resolutions, the option to set the minimum and maximum visibility level is particularly useful. This allows MOHID Studio to show always an image with the appropriate resolution, without being very memory demanding.
One example of a raster collection can be seen in Figure 8.
WMS Layers are provided by online servers over the Internet. MOHID Studio has two preconfigured WMS Servers: (i) Demis Map and (ii) JPL Nasa. WMS Layers can be added by selecting "WMS" on the Background group from the Map menu (see Figure 1). A window like the one represented on Figure 9 will appear. In this is possible to select from one of the predefined WMS Servers or to add the name address (URL) to a user defined WMS Server. After selecting the server, press the "Get Layers" button to obtain the list of possible WMS layers.
NOTE: There are several different WMS versions. MOHID Studio only supports WMS versions 1.0.0, 1.1.0, 1.1.1 and 1.3.0.
The Figure 10 shows an example of the WMS layer for Europe (from DEMIS map) inside the MOHID Studio.
MOHID Studio can display, as background image, tiles from Google Maps, Bing Maps and Open Street Map. Web Tiles layers can be added by pressing the "Web Tile" button on the group Background from the Map menu (see Figure 1). The Load Tile Layer window, represented on Figure 11 will appear. In this window is possible to select one of the supported Web Tile providers list.
NOTE: When adding Web Tile layers, the map projection must be set to Web Mercator (automatically asked to user).
On Figure 12 is represented an example of a simple application using the Web Tile Layer (Bing-Aerial) in MOHID Studio.
MOHID ASCII layers are special layers to load files which contain simplified information about geometries specific to the usage of MOHID Water Modelling System. These layers include: (i) XYZ Points, (ii) Grids, (iii) Grid Data, (iv) Drainage Network and (v) Polygons.
As an example, Grid Data files are used by MOHID Water to read information about the bathymetry.
Some tools included into MOHID Studio use information from this layer while other tools help to create specific MOHID ASCII Files.
As an example, to create a bathymetry (Grid Data File) it is necessary to load:
XYZ Point layers are loaded from XYZ Files and are used as input to create Grid Data Files. A XYZ Point layer can easily be added by pressing the button "XYZ Points" on ASCII group from the "Map" menu (see Figure 1).
After selecting a valid XYZ file, a window like the one represented in Figure 13 will appear. By default, the layer name is generated based on the filename, the minimum and maximum visibility are set to "always" visible and the layer style is set to the default’s gradient style, respecting the minimum and maximum values found in the XYZ file.
On the Figure 14 is represented an example of a XYZ Point Layer displayed in MOHID Studio.
Grid layers are loaded from Grid files (for more information read subsection 10.1.5). A Grid layer can be added by pressing the button "Grid" in ASCII group from the "Map" menu (see Figure 1). The process of adding a Grid Layer is similar to the process of adding a XYZ Point layer. On the Figure 15 is represented a Grid Layer showing part of a curvilinear grid.
Grid Data layers are loaded from Grid Data files. A Grid Data layer can be added by pressing the "Grid Data" button on ASCII group, from the "Map" menu (see Figure 1). The process of adding a Grid Data layer is similar to the process of adding a XYZ Point layer. On the Figure 16 is represented a Grid Data Layer of the bathymetry of the Tagus Estuary.
Drainage Network layers are loaded from Drainage Network files. A Drainage Network layer can be added by pressing the "Drainage Network" on the ASCII group, from the "Map" menu (see Figure 1). The process of adding a Drainage Network layer is similar to the process of adding a XYZ Point layer. On the Figure 17 is represented a Drainage Network Layer of the Trancão Watershed.
Polygons layers are loaded from Polygon files. A Polygon layer can be added by pressing the "Polygons" button on the ASCII groups from the "Map" menu (see Figure 1). The process of adding a Polygon Layer is similar to the process of adding a XYZ Point layer. On the Figure 18 is represented a Polygon Layer representing the boundaries of a watershed.
MOHID uses HDF files to store information about large data sets. Within MOHID, HDF files are primarily used to store model results, but they may also be used to provide boundary conditions or initial conditions.
MOHID uses HDF files with some special groups / datasets, in order to store time based and georeferenced data sets. Dataset can apply to grid based (sometimes referenced as polygon based) datasets, vector field datasets, drainage network data sets and lagrangian particle data sets.
HDF Grid Map layers are the most common HDF layers used in MOHID Studio. A HDF Grid Map layer allows to display the temporally evolution of a grid based property from the information stored in a single HDF file. An HDF Grid Map layer can be added by pressing "HDF Map" in HDF group from the "Map" menu (see ???).
After selecting a valid HDF file, a window like the one represented in Figure 19 will appear.
This window (see Figure 19) has several options about which and how the data is presented:
The other options available on this window, represented in the Figure 19, have been already explained in this manual.
After adding a HDF Grid Map layer, the time animator window will be enabled (Date & Time controller, located below the Layer List – represented in Figure 2). Using this animator it is possible to loop trough individual layers of the HDF Grid Map. To start or stop the animation use the Date & Time Controller.
HDF Vector Field layers are used in MOHID Studio to display the temporally evolution of a vector field based on the information stored in a single HDF file. HDF Vector Field layer can be added by pressing "Vector Field" on the HDF group from the "Map" menu (see Figure 1). The window that will open is similar to the one represented in Figure 19, with the difference that the available features are vector fields (with X and Y components). In Figure 20 is represented a Vector Map of the current velocity at the Tagus Estuary Mouth.
HDF Drainage Network layers are used in MOHID Studio to display the temporally evolution of properties inside a drainage network based on the information stored in a single HDF file. A HDF Drainage Network layer can be added by pressing the "Drainage Network" button on the HDF group, from the "Map" menu (see Figure 1). A window like the one represented in the Figure 19 will appear in order to configure the HDF layer.
HDF Lagrangian Particle layers are used in MOHID Studio to display the temporally evolution of properties of lagrangian particle, based on the information stored in a single HDF file. A HDF Lagrangian Particle layer can be added by pressing "Particle Field" on the HDF group from the "Map" menu (see Figure 1). The window that will be open is similar to the one represented in Figure 19.
Besides the MOHID specific vector data formats listed previously, MOHID ASCII Layers and HDF Files, other vector layers can be loaded into MOHID Studio’s GIS engine. Providers of these layers are: (i) ESRI Shapefiles, (ii) XML Geometries and (iii) HGT Layers.
ESRI Shapefiles are widely used to store geographic data. Layers based on data from ESRI Shapefiles can be loaded to MOHID Studio by pressing the button "SHP" (Shapefile) on group Vector Data from the "Map" menu (see Figure 1). A window similar to the one represented in Figure 13 will appear, after selecting the shapefile to open.
XML Geometries are layers based on XML files which contain geometries stored by MOHID Studio. Layers based on XML Geometry files can be easily loaded into MOHID Studio, by pressing the button "XML" (XML Geometry) on Vector Data group from the "Map" menu (see Figure 1). After selecting the xml to open a window similar to the one that is represented in Figure 13 will pop out in order to configure the new layer.
HGT layers are based on NASA SRTM (Shuttle Radar Topography Mission) files and are the main source for building digital terrains for MOHID Land. HGT Layers can be added by pressing the button "HGY" (NASA HGT) on group Vector Data from the "Map" menu (see Figure 1). A window like the one represented in Figure 21 will appear.
In the HGT Vector Layer window (represented in Figure 21) is necessary to specify the geographic region for which the HGT layer is to be loaded: (i) the current view or (ii) the boundaries of a given layer.
After selecting the region, the necessary HGT files will be automatically downloaded from NASA’s FTP server and cached on your local computer.
NOTE: Downloading and displaying HGT layers for big areas can be time consuming and generate a lot of internet traffic. It is recommended that the user should not try to load HGT layers that cover more than 4 square degrees at once.
Hello Manage Custom Layers
Label layers are a special kind of layer which allows to quickly obtain information about the numerical data represented by a given vector layer. Label layers can be created be choosing "Create Label Layer" from the context menu in the Layers List. In the Figure 23 is represented an example showing how to create a label layer from a vector layer.
Layers are displayed in the map on top of each other, considering the same order as shown in the Layers List (the topmost layer in the Layers List is also the topmost layer in the Map Display). Layers can be moved up and down through the context menu of the Layers List or by pressing the buttons "Move Up" or "Move Down" in the Manage Layers group from the "Map" menu (see Figure 1). Layers can also be removed from the map through the context menu of Layers List or by pressing "Remove" on Manage Layers group from the "Map" menu (see Figure 1).
Vector layers are rendered based on their current layer style. Layer styles can be "simple" or based on the feature data which is represented. Different layer styles can be applied to different vector layers, depending on the type of the style and type of the layer.
Layer styles of a given layer can be accessed by selecting "Edit" in the layers properties window. In the Figure 24 is represented an example of how to access the layer style.
NOTE: Properties of a layer can be accessed by: (i) double clicking over it on the Layers List, (ii) selecting "Properties" from context menu of the Layers List (see Figure 4) or (iii) by pressing F4.
MOHID Studio allows creating style templates to reuse as predefined layer styles. Template styles can be applied by hitting the "Apply" button, represented in Figure 24.
A simple vector style can be applied to almost any type of vector layers. A simple vector style renders all geometries in the same way, independent of the feature data.
Simple Vector Styles are applied by default to MOHID ASCII Polygon layers, XML Geometry layers and ESRI Shapefile layers.
In the Figure 25 is represented the window which allows configuring a simple vector style. Depending on the geometry to be rendered, different styles are used:
In the Figure 27 it is possible to see two images of the same map but using different simple vector styles. On the first map, the top map, country borders are represented by simple yellow lines and the cities are represented with white markers. On the second map, the bottom one, the country borders are represented by black lines, the areas are filled in with transparency and the cities are represented with green circle markers.
Gradient layer style can be applied to almost any type of vector layers. A gradient layer styles render geometries based on the feature data, applying a gradient color scale between a minimum and a maximum value.
Gradient Layer Styles are applied, by default, to MOHID Grid Data layers, HDF Grid Map Layers, HDF Drainage Network Layers and HDF Lagrangian Layers.
In the Figure 28 is represented the window where is possible to configure a gradient layer style and in the Figure 29 is represented, in MOHID Studio, a grid data layer with a gradient layer style applied.
Transparency Layer Style can be applied to almost of any type of vector layers. A transparency layer style render geometries based on the feature data consist on a transparency color scale between a minimum and a maximum value.
Classified Layer Style can be applied to almost any type of vector layers. A classified layer style renders geometries based on the feature data consists on a classified color scheme (each color is defined between a range of values).
Arrow Layer Styles are the only type of styles which can be applied to vector fields. Arrow layer styles render arrows with a given color. The size of arrows is based on a linear correspondence between a minimum and maximum modulus values of the vector and the minimum and maximum pixel sizes of the arrows.
In the Figure 34 is represented the window to configure the Arrow Layer Style and in the Figure 35 is the represented, in MOHID Studio, the application of the arrow layer style to a vector field layer.
MOHID Studio allows the user to define several style templates to use in different workspaces. To define a new style templates (or modify an existing one), press the button "Style Manager" on the group Manage Layers from the "Map" menu (represented in Figure 1). A window like the one represented in Figure 36 will appear. Here it is possible to add, edit or remove style templates.
Style templates can be applied to a layer, by selecting "Apply" in the layer style properties window (represented in Figure 24).
Data displayed by vector layers can be queried and displayed in a tabular form. In order to perform a query, on a given layer, it is necessary to select first, in the Layers List, the chosen layer to perform the query. After selecting the layer, the selected row will turn orange. Now, it is possible to query the data by activating the query tool from the map tool box (as shown in Figure 3) and then selected region or draw one (by pressing the left mouse button) where to perform the query. The results of the query will be displayed in the query result window. In the Figure 37 is represented the operation of querying the map.
MOHID Studio allows to saves the current map as an image or as an animated gif. To save a single image or an animation, press the button "Save Image" or "Save Animation" on group Images, from the "Map" Menu (see the Figure 1). A window similar to the one represented in Figure 38 will appear, in order to configure the image/animation to save.
From this window, represented in Figure 38, is possible to configure the layout of the image to be saved, for example: legends, north arrow, scale used and marker lines. By pressing the "Save" button, the image or animation will be saved in the selected path with the selected filename.
MOHID Studio supports coordinate transformation on the fly, so layers with different coordinate system can be overlaid. Whenever a new layer is added to the map, the information about its coordinate system must be provided. This happens every time a new layer is added through the dialog boxes (which have been presented previously in the section, for example: Figure 11 and Figure 13). In each of these dialog window appears a box, represented in Figure 39. Using this box it is possible to specify the coordinate system of a given layer.
MOHID Studio map displays the layers in its own coordinate system. The current map coordinate system can be changed through the general map configurations. The map configurations are accessible through the small icon located in the upper right area of the map window (highlighted in the Figure 40). The map configurations windows is represented in the Figure 41.