The large amount of information available in the Geographical Information Systems makes it necessary to use an application that allows the user to configure, by means of an interactive and intuitive environment, the access to specific detailed data. The application is based on a few selection criteria to display in every moment the information that the user wants to see. This way, the user must choose between overlain layers containing information which cannot be viewed at the same time.
One may access through the web page of the Wind Atlas of Spain by clicking in the link named " Access to the application ", inside the paragraph " Data access " located in the left margin of the page. This done, this is the overall view obtained:
The greatest area of the application is occupied by the Display Map. By default, the main wind speed map at 80 m height appears (represented by shaded contours), showing the whole Iberian Peninsula, the Balearic Islands, Ceuta and Melilla.
This display map adapts its content to the navigation instructions given by the user, through the tools located in the top horizontal bar and in the frames arranged in the left margin. In the low right corner of the frame, the map scale appears. This is at all times adapted to the visualized map.
Three classes of tools are distinguished attending to their functionality:
All the mentioned tools are depicted below in detail. When using them, the application may need a few moments to refresh the desired view, due to the large amount of information it handles. In case of error or absence of data after refreshing the screen, it is recommended to click the button "update" of the browser (if this does not work, it could be necessary to close and re-open the application).
Selection of the visual environment: "Canarias" - "Peninsula, Baleares, Ceuta and Melilla ":
Due to the physical distance and the need to make the study in two different coordinate systems - UTM WGS84 for the Canary Islands and UTM ED1950 for the rest of Spain - data are divided in two separate maps. To access each of them, the user must click in the corresponding checkbox in the top right margin:
Button group on the left margin of the horizontal bar:
With this tool, the application allows to navigate to a certain place in the map in the quickest possible way: specifying the name of a town, or introducing the coordinates of the requested point.
This is the application's core, where all wind resource data and complementary information reside. Data are grouped in sets of elements called layers, which are in turn grouped in layers attending to the common features between them. To display hierarchies in a group of layers, press at the left of the group's name (which will turn into ). The layers and/or sub-groups hierarchically under will open; in the case of layers, pressing again will open the layer's symbology (legend), so that the data represented in the map can be interpreted (pressing again will contract the symbology).
Example: after opening the application, in the frame " Cartography " the names of the main categories of every group appear: "Wind resource", "Administrative divisions", "Protected areas (CCAA)", etc. Plunging deeper into "WIND MAPS" - "main annual wind speed(m/s)" - "at 80 m", the layer symbology is shown, consisting of the colour scale represented on the foreground wind map screen when opening the application.
It can be noticed that all the layer groups in the way (as well as the final layer) have the checkbox marked , which means that the final layer will be visible; in this sense, if only one of the intermediate checkboxes is not marked , the final layer will not be seen, regardless of its own checkbox state.
There are two possible cases in which the layer is activated but not displayed in the map:
-Going back to the previous example, if inside "wind maps" the layer "Topography and surface roughness" - "Contours (m)" is activated, no change would be experienced in the main map displayed. This happens because this layer occupies a place lower than the previous one, so with both layers covering the whole territory, it is not possible to display it until the layer on top is unmarked. To summarise, one layer covers another which lies below in the area where they intersect. To make browsing easier and optimise the application's utility, an exception exists to this, affecting the layers in the group "national topographic map". Here, a transparency level has been defined so that all layers can be visible at the same time (to notice this, the group must be activated and the display must be zoomed to an area in the map).
- Exploring the layers of this group, the second case will occur: it is observed that four layers are marked, although only one is and the other three in a greyish tone (as well as their names in gray). This means that these layers are activated but the map scale does not match their display range; the layers from this group with higher resolution will become visible at a closer zoom into an area of the map.
To have a wider vision of the frame content "Cartography", the frames "Search" and "Map of situation" can be contracted by clicking on the icon in each one. If several layer groups are opened, a vertical shift bar will appear on the right side of the frame. In the lower end, the mouse arrow will change its shape to . Here the user can drag the bar down to stretch the frame.
This tool is only available for three layers - those from the group "Wind resource" (inside the frame "Cartography ")-. These have a set of discrete elements, represented by colour-filled circles (as seen in their symbology). Each of them has an associated text file or image that opens when clicking the point. To request data from a layer, select it in the menu which appears when clicking , with the layer active (in the frame "Cartography" - "Wind Resource") and the button checked, so that now the mouse arrow will turn into a when placing it on the map.
If the chosen layer is not activated, or when the user clicks away from the point, or if the activated layer and the selected layer in the menu do not match, the tool will display an error message. At any time, the returned coordinates by the tool correspond to the projection of the map: UTM ED1950 for the Iberian Peninsula, Baleares, Ceuta and Melilla; and UTM WGS1984 for the Canary Islands.
This tool allows to estimate the energy production a wind turbine would provide on a certain point of the National territory, expressed in terms of raw and net energy (MWh/year). To carry out this calculation, it is firstly necessary to select the button , and next click on a point in the map. A new window opens, where the user must specify the power curve parameters [value of Production (KW) for every Speed (m/s), according to manufacturer specifications] for the wind turbine object of estimation. To launch the calculation, the button "Calculate" must be clicked.
To estimate the net energy, the tool uses a default global loss coefficient of 15% (the user can introduce his/her own estimation), that considers production losses owing to farm and network technical downtime, electric losses, wake effects, etc.
Additionally, the calculation window for equivalent hours indicates the UTM coordinates of the point, its elevation and roughness, and the Weibull coefficients estimated at the site.
Note: It is important that the user bears in mind the uncertainty boundaries associated to these results. Not all wind turbines in the market can be installed in a specific spot with technical guarantees (the Wind Atlas modelling cannot estimate site types). For more precise estimations of wind resource, 'in situ' long enough measure campaigns must be performed with the suitable instrumentation during long enough periods.
It gives a more general vision than that of the central display map. In the starting scale (vision of the whole Spain), provincial boundaries appear. By zooming on an area on the central map (it is not allowed on the situation map), the names of the provinces would appear, and eventually also the municipality boundaries labelled with their names. The situation map can also be used to navigate: for that, it is necessary to place the mouse pointer inside the red rectangle and drag it towards the region of interest (this option preserves the scale of the display map). Alternatively, the area of interest (the region displayed inside the main or central map) can be moved by defining the size of the red rectangle: this is done by looking for the spot in the lower right corner of the red rectangle where the mouse pointer turns into (see figure); by dragging this vertex, the user can change the area of interest. Changes will occur both in the situation map and in the main map. The display will adapt to the resulting resolution and scale.