Lagna Chart or the Ascendant chart is a chart on which the Snapshot of the Position of all the planets and rashis are casted .It has 12 houses of 30 degree each representing the 1/12th portion of the sky starting from the eastern horizon . Also transiting through it are the 12 rashi also divided in 30 degree each. Placement of planets is done according to their position in house & signs correspondingly. It is considered the most important chart in vedic astrology.
Lagna or ascendant is the Sign which rises on the Eastern horizon when the person is born. Once the birth chart is casted then it is the sign in the first house of the birth Chart. It is most important house in the chart as it literally represents you , your health , personality , nature , temperament , magnitude of success in life and your fame are can be deciphered by checking the first house or Lagna or you Chart.