1. From the Lagna
2. From the Moon (Chandra Lagna)
3. From the Sun (Surya Lagna)
You would determine their respective strength by analyzing the Shadbala (SB) scores of the lord of the Lagna, Moon and Sun. Many computer software programs can calculate this for you. The scoring posits that 1 is neutral, above 1 is getting stronger and below 1 is getting weaker. A score of 1.5 or higher means that the planet is very strong where as a score below 0.7 is very weak.
Although all three sources have useful information when analyzed, sometimes one of them is much stronger than the others, if it is only one that is strongest, then it is termed Most Predominant Lagna (MPL). In this case, focusing on the MPL will yield more targeted and accurate results in analysis.
A good example of where the MPL is the Chandra Lagna is Jim Morrison. From the above chart we can see that his Moon shadbala score is 1.42, Sun is 1.10 and Saturn (lord of lagna) is 1.03. Thus, his life story is most clearly and accurately described by analyzing the chart with the Moon as the ascendant. In this case, the original position of the Moon in the 4th bhava will mean that 4th bhava matters are very much emphasized in his life.
First, the Moon’s karakas and karakatwas include the home and early childhood, which was very challenging and unconventional. From the Chandra Lagna, malefic Mars retrograde and in an enemy sign (Taurus) is in the 2nd house contributing to family problems. According to Astrodata bank, the family moved four times before Jim was 4 years old (1). Because his father was an officer in the Navy, he was usually away from home and he was mainly raised by his mother. She was considered eccentric and was too busy with her other kids to give that much attention or discipline to Jim. During college, he made a career decision his parents didn’t approve of, his parents disowned him and he became estranged from them claiming they were deceased (1).
Second, there are multiple connections between the Moon and third bhava showing that many of Jim's interests are governed by the third bhava:
1. The third bhava governs self- expression through music and Jim became a very famous singer and song writer with his band The Doors.
2. The third bhava governs poetry and although not as well known for poetry, Jim devoted significant time to this passion and composed several poems over the course of his life. He said "If my poetry aims to achieve anything, it's to deliver people from the limited ways in which they see and feel" (2). You can read some of his poetry online at http://hellopoetry.com/james-douglas-jim-morrison/
3. The third bhava governs film so it makes sense that Jim's undergraduate degree was in film and he made several films while studying.
In his chart, the third bhava ruler Jupiter makes a special trine aspect onto the Moon in the 4th bhava from the 8th bhava. The Moon’s dispositor Mars is in Taurus which governs the throat and gives talent in singing. Mars in the 5th bhava also makes a special forward square aspect onto Jupiter, providing an additional connection of the Moon with the 3rd bhava. From the Chandra Lagna, Mars is in the 2nd bhava of singing ability and as the dispositor of the 1st house, personalizes this talent. Mars represents fire so it is perfectly fitting that his song "Light my Fire" with his band The Doors in 1967 was what gave him widespread fame and it spent 3 weeks in the summer at number 1 on the Billboard Hot 100 (3).
Third, the Moon also governs intelligence and Jim had an IQ of 149, was a good student, a voracious reader and found school easy (1, 4). The Moon is placed in the 4th bhava governing education and he generally found school easy, was on the dean’s list in his freshman year at university and after switching to UCLA's film school, obtained his undergraduate degree.
Fourth, the 4th bhava represents vehicles and there was a very notable incident of four year old Jim witnessing a car accident where a family of Native Indians was severely injured and possibly dead on the road. Jim felt that their ghosts were around and that some of them entered him. Ketu represents problems with ghosts In the lagna chart, Ketu is conj the Asc 4 degrees and from Chandra Lagna, Ketu is in the 10th house, highlighting Ketu's importance in both charts.
“When in Albuquerque, NM, he experienced "the most important moment of my life. “Me and my mother and father and my grandmother and grandfather were driving through the desert at dawn. A truckload of Indian workers had hit another car or something - there were Indians scattered all over the highway, bleeding to death. So we pulled the car up. I must have been about four or five. I had to stay in the car while my father and grandfather went to check it out - all I saw was funny red paint and people lying around, but I knew something was happening, because I could dig the vibrations of the people around me. And all of a sudden I realize that they didn't know what was happening any more than I did. That was the first time I tasted fear...and I do think, at that moment, the souls or the ghosts of those dead Indians - maybe one or two of 'em, were just running around, freaking out, and just leaped into my soul, and I was like a sponge, ready to just sit there and absorb it...And they're still in there. It's not a ghost story, it's something that really means something to me." (1).
In addition there was another mystery surrounding his lost 1967 Shelby GT 500 which has not been solved to this day. There are multiple stories floating around of what may have occurred but no one knows for sure (5).
Fifth, the Moon represents emotions and the fourth bhava if unfavourable gives emotional problems. Jim was depressed and it can be reasonably inferred that his drug and alcohol addictions stemmed from emotional difficulties. Rahu and Ketu are associated with poisons such as drugs and alcohol. Rahu-Ketu on the angular axis of 4-10 in the Chandra Lagna or 1-7 in the Lagna (and aspecting the Asc very tightly by 4 degrees) show his struggle being prominent within him and publicly visible.
The Rahu-Ketu prominence is also shown through the naming of the band The Doors. The name was inspired by Aldous Huxley's book detailing his experience taking mescaline, The Doors of Perception. Huxley got the name from William Blake's line "If the doors of perception were cleansed everything would appear to man as it is, infinite " (6). Perhaps Jim felt that by taking drugs he was cleansing his own perception to see the true reality of the world.
From the Chandra Lagna, Saturn is retrograde in the 3rd bhava, showing that there is grief and significant difficulties relating to his self expression in musical performances. Also from the Chandra Lagna, Ketu is in the 10th bhava of career and therefore its characteristics become publicly associated with Jim. On the negative side, Ketu represents depression and chronic dissatisfaction. He showed his troubled emotions publicly with outrageous and violent antics and profane language during his musical performances (4, 7).
Sixth, the Moon is in Aries partially accounting for his rebelliousness and distaste for authority figures (4). On The Doors original Elektra Records bio he stated: “I’ve always been attracted to ideas that were about revolt against authority. I like ideas about the breaking away or overthrowing of established order. I am interested in anything about revolt, disorder, chaos – especially activity that seems to have no meaning. It seems to be to be the road toward freedom...” (7).
Seventh, the Moon represents women and although Jim was involved in a serious romantic relationship with Pamela Courson for most of his life, he was an “infamous womanizer” (4).
Eighth, baths are a 4th bhava signification and heart problems are the result of an unfavourable 4th house. Jim died of heart failure in the bathtub of his Paris apartment (1).
We can see that Jim Morrison is a prime example of the importance of analyzing the Vedic chart from the Chandra Lagna, especially if it is the Most Predominant Lagna.
5. http://www.examiner.com/article/jim-morrison-s-lost-1967-shelby-gt-500-haunted-ghost-story https://rockhall.com/inductees/the-doors/bio/