The "Topographic Horizon Elevation" refers to the elevation angle of the topography surrounding your solar farm site.

More specifically, the elevation angle is a measure (in degrees) of the extent of the surrounding hills or mountains rise above the horizon.

The elevation angle must be paired with an azimuth angle, which provides the compass direction of the elevation angle estimate.

Elevation angles are limited to 0 (flat) to 90 (vertical) degrees. In practice, elevation angles will rarely exceed 20-30 degrees above the horizon.

Azimuth angles follow the coordinate system outlined in our API documentation, and are as follows:

Example: User Estimate of Topographic Elevation Angle by Azimuth

In the following example, we have a solar farm facility surrounding by complex terrain, of varying topographic elevation angle:

It is the responsibility of the user to estimate or measure the elevation angle of the topography surrounding the solar facility. There are many commercial tools available for this process, including some which are open source, with varying degrees of user friendliness. In future, Solcast will use local elevation information to create a 'smart guess' and pre-fill these values for you.

Continuing the example with elevation angles determined, the user will then need to specify the range of azimuth angles for which each elevation angle applies:

Example 2: Copy and Paste

The horizon elevations can be provided as a comma-separated list of values. The example below represents the elevations illustrated in the image above.

  • One line per defined point.
  • Each point as a comma-separated pair of Azimuth and Elevation
  • The Azimuth and Elevation both expressed in degrees.
20,0
19,0
18,0
17,0
16,0
15,0
14,0
13,0
12,0
11,0
10,0
9,0
8,0
7,0
6,0
5,0
4,0
3,0
2,0
1,0
0,0
-1,0
-2,0
-3,0
-4,0
-5,0
-6,0
-7,0
-8,0
-9,0
-10,0
-11,0
-12,0
-13,0
-14,0
-15,0
-16,0
-17,0
-18,0
-19,0
-20,0
-21,0
-22,0
-23,0
-24,0
-25,0
-26,0
-27,0
-28,0
-29,0
-30,0
-31,0
-32,0
-33,0
-34,0
-35,0
-36,0
-37,0
-38,0
-39,0
-40,0
-41,0
-42,0
-43,0
-44,0
-45,0
-46,0
-47,0
-48,0
-49,0
-50,10
-51,10
-52,10
-53,10
-54,10
-55,10
-56,10
-57,10
-58,10
-59,10
-60,10
-61,10
-62,10
-63,10
-64,10
-65,10
-66,10
-67,10
-68,10
-69,10
-70,10
-71,10
-72,10
-73,10
-74,10
-75,10
-76,10
-77,10
-78,10
-79,10
-80,10
-81,10
-82,10
-83,10
-84,10
-85,10
-86,10
-87,10
-88,10
-89,10
-90,10
-91,10
-92,10
-93,10
-94,10
-95,10
-96,10
-97,10
-98,10
-99,10
-100,10
-101,10
-102,10
-103,10
-104,10
-105,10
-106,10
-107,10
-108,10
-109,10
-110,10
-111,10
-112,10
-113,10
-114,10
-115,10
-116,10
-117,10
-118,10
-119,10
-120,10
-121,10
-122,10
-123,10
-124,10
-125,10
-126,10
-127,10
-128,10
-129,10
-130,10
-131,10
-132,10
-133,10
-134,10
-135,5
-136,5
-137,5
-138,5
-139,5
-140,5
-141,5
-142,5
-143,5
-144,5
-145,5
-146,5
-147,5
-148,5
-149,5
-150,5
-151,5
-152,5
-153,5
-154,5
-155,5
-156,5
-157,5
-158,5
-159,5
-160,5
-161,5
-162,5
-163,5
-164,5
-165,5
-166,5
-167,5
-168,5
-169,5
-170,0
-171,0
-172,0
-173,0
-174,0
-175,0
-176,0
-177,0
-178,0
-179,0
-180,0
179,0
178,0
177,0
176,0
175,0
174,0
173,0
172,0
171,0
170,0
169,0
168,0
167,0
166,0
165,0
164,0
163,0
162,0
161,0
160,0
159,0
158,0
157,0
156,0
155,0
154,0
153,0
152,0
151,0
150,0
149,0
148,0
147,0
146,0
145,0
144,0
143,0
142,0
141,0
140,0
139,0
138,0
137,0
136,0
135,20
134,20
133,20
132,20
131,20
130,20
129,20
128,20
127,20
126,20
125,20
124,20
123,20
122,20
121,20
120,20
119,20
118,20
117,20
116,20
115,20
114,20
113,20
112,20
111,20
110,20
109,20
108,20
107,20
106,20
105,20
104,20
103,20
102,20
101,20
100,20
99,20
98,20
97,20
96,20
95,20
94,20
93,20
92,20
91,20
90,20
89,20
88,20
87,20
86,20
85,20
84,20
83,20
82,20
81,20
80,20
79,20
78,20
77,20
76,20
75,20
74,20
73,20
72,20
71,20
70,20
69,20
68,20
67,20
66,20
65,20
64,20
63,20
62,20
61,20
60,20
59,20
58,20
57,20
56,20
55,20
54,20
53,20
52,20
51,20
50,20
49,20
48,20
47,20
46,20
45,20
44,20
43,20
42,20
41,20
40,20
39,20
38,20
37,20
36,20
35,20
34,20
33,20
32,20
31,20
30,20
29,20
28,20
27,20
26,20
25,20
24,20
23,20
22,20
21,20

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