In the process of sunshine map interpretation, whether the partial map is converted to the overall map or the combined map is converted to the common map, the following two aspects should be paid attention to during the conversion:

1.繪制轉(zhuǎn)換新圖時(shí)，一定要明確圖上點(diǎn)、線、面的空間關(guān)系。歸納起來(lái)主要有：

1. When drawing a new transformation diagram, be sure to clarify the spatial relationship of points, lines and surfaces on the diagram. To sum up, it mainly includes:

(1)地軸、直射點(diǎn)的太陽(yáng)光線一定通過(guò)地球球心。

(1) The sun's rays at the earth's axis and direct point must pass through the earth's center.

(2)太陽(yáng)光線所示的平面為黃道平面，黃道平面與赤道平面成23°26′的夾角。

(2) The plane shown by the sunlight is the ecliptic plane, which forms an included angle of 23 ° 26 'with the equatorial plane.

(3)各緯線圈與赤道平行、與各經(jīng)線相互垂直。

(3) Each weft coil is parallel to the equator and perpendicular to each longitude.

(4)各經(jīng)線都相交于南北兩極點(diǎn)。

(4) Each meridian intersects the north and south poles.

(5)晨昏線與各緯線既可垂直，也可斜交;與極圈內(nèi)的各緯線還可相切、相離(極圈上出現(xiàn)極晝或極夜);平分赤道(即赤道與晨昏線的兩交點(diǎn)經(jīng)度相差180°，即赤道晝夜平分);與各經(jīng)線既可斜交，也可重合。

(5) The morning twilight line can be perpendicular or oblique to each weft line; It can also be tangent and separated from the weft lines in the polar circle (polar day or night appear on the polar circle); Bisector the equator (i.e. the longitude difference between the two intersections of the equator and the morning dusk line is 180 °, i.e. the equator bisects day and night); It can skew or coincide with each meridian.

(6)晨昏線把相交的各緯線圈分為晝弧和夜弧，根據(jù)晝弧和夜弧的長(zhǎng)度(所跨經(jīng)度)可確定該緯線的晝夜長(zhǎng)短;如果與各緯線垂直，則晨昏線必定通過(guò)南北兩個(gè)極點(diǎn)，且該日全球晝夜平分。

(6) The morning twilight line divides the intersecting weft coils into day arc and night arc, and the day and night length of the weft can be determined according to the length (longitude) of day arc and night arc; If it is perpendicular to each latitude line, the morning twilight line must pass through the north and south poles, and the global day and night equinox on that day.

2.把握好時(shí)間點(diǎn)的轉(zhuǎn)換。轉(zhuǎn)換時(shí)的注意事項(xiàng)主要有：

2. Grasp the conversion of time points. Precautions during conversion mainly include:

(1)赤道上晝夜始終平分，晨昏線與赤道的交點(diǎn)位置可以通過(guò)時(shí)間計(jì)算(6時(shí)、18時(shí))或通過(guò)經(jīng)度判讀在新圖中找到。

(1) Day and night are always equinox on the equator. The intersection position of the morning twilight line and the equator can be found in the new map through time calculation (6:00, 18:00) or longitude interpretation.

(2)晨昏線與緯線圈切點(diǎn)位置的確定，可以通過(guò)切點(diǎn)時(shí)間(12時(shí)、0時(shí)或24時(shí))推算出經(jīng)度，再通過(guò)直射點(diǎn)位置確定其緯度。

(2) For the determination of the tangent position of the morning twilight line and the latitude coil, the longitude can be calculated through the tangent time (12:00, 0:00 or 24:00), and then the latitude can be determined through the direct point position.

(3)晨昏線與赤道的交點(diǎn)、與緯線圈切點(diǎn)位置確定后，就可用平滑曲線連接起來(lái)，但要注意太陽(yáng)光線與晨昏線始終垂直。

(3) After the intersection of the morning twilight line and the equator and the tangent point of the latitude coil are determined, it can be connected with a smooth curve, but it should be noted that the sun light is always perpendicular to the morning twilight line.

(4)太陽(yáng)直射點(diǎn)永遠(yuǎn)位于南北回歸線之間，晨昏線與緯線圈相切的點(diǎn)永遠(yuǎn)位于極圈上及其以內(nèi)。

(4) The direct point of the sun is always between the Tropic of cancer, and the point tangent to the weft coil is always on and within the polar circle.