The horizon represents the terrain skyline around the selected location and it is generated from digital elevation model. The relevant shading of the modules throughout the year is calculated from this horizon. It is usually sufficient for PV systems, which are placed in the open landscape. However, typically in urban areas other objects (like high buildings, trees, etc.) may influence the real horizon on the particular location. Therefore the applications like pvPlanner or pvSpot support the manual adaptation of the horizon using interactive horizon editor.
Editing the horizon can be done in a pop-up window (example below):
while editing, Undo and Redo functions can be used anytime
tools for uploading and mastering background photos or horizon maps
reset all changes and get the initial horizon
text editor allows you to change the horizon by (re)typing the values
sun-paths throughout the year (the upper and lower line represent sun paths during the solstice days, central line during the equinox days)
a) mouse cursor, b) position of the cursor on the sun path graph
click Apply button to restart pvPlanner simulation with the alternated horizon or Cancel to leave the editor without applying any changes
The horizon can be modified by
(re)typing the numeric values in the text editor (box 4); in format azimuth:elevation, where azimuth: 0 = North = 360, 90 = East, 180 = South, 270 = West
(re)drawing a new horizon using the mouse or touchpad directly in the graph (click left mouse button down and hold → move the mouse → release mouse button → repeat the process to modify the horizon); the numbers in the text editor (box 4) are updated automatically according to the actual changes); the values of the actual cursor position in the bottom-left corner (Azimuth, Elevation, Horizon elevation) might be helpful for better navigation
If the horizon of your location is documented on photos, graphs or horizon maps, upload them (1) and resize and displace in the graph (2) as precisely as possible (see the example on the scheme below). If not, simple geometric estimation with goniometer can be used.
Then in the upper menu switch to Edit horizon mode and continue with modifying the horizon (3). The functions hide/show photos or undo, redo might be helpful during this process. When done (4), click Apply button and pvPlanner will start the simulation process with a new horizon. The results should be noted in PV conversion losses and performance ratio table in the line informing about shading losses.
HINTS with positioning the pictures correctly:
if you try to take panorama photo(s) for this purpose by yourself, we recommend you to use the tripod with level bubble (or alternative device) and take the picture with the leveled camera
some modern cameras save the azimuth and angle with the taken pictures; check the meta information of such pictures
many freeware or shareware software support the creation of panorama view from more pictures automatically or semi-automatically
iMaps can help you to determine the azimuths. Find your location on the satellite map, identify few objects common with your panorama pictures (e.g. the corner of significant building, solitary tree, crossroads, etc.) and calculate the right azimuth between the object and your location. Alternatively use a compass to mark the main directions (East, South, West) when taking the pictures
don't worry if you cannot reach a very high level of precision; in the example presented above it is always more accurate to modify the default horizon with some data than do nothing; small imprecisions are often acceptable