Question:
REO Speedwagon (originally styled as R.E.O. Speedwagon) is an American rock band from Champaign, Illinois. Formed in 1967, the band cultivated a following during the 1970s and achieved significant commercial success throughout the 1980s. Hi Infidelity (1980) contained four US Top 40 hits and is the group's best-selling album, with over ten million copies sold. Over the course of its career, the band has sold more than 40 million records and has charted thirteen Top 40 hits, including the number ones "
By the late 1980s, the band's popularity was starting to decline. Alan Gratzer left in September 1988 after he decided to retire from music to open a restaurant. In early 1989, Gary Richrath quit after tensions between him and Kevin Cronin boiled over. Cronin had been playing in The Strolling Dudes, a jazz ensemble that included jazz trumpet player Rick Braun (who had co-written the abovementioned "Here With Me" with Cronin), Miles Joseph on lead guitar and Graham Lear on drums. Lear had already been invited to join REO in September 1988 as Gratzer's successor and Joseph was brought in as a temporary stand-in for Richrath. Back up singers Carla Day and Melanie Jackson were also added. This lineup did only one show, on January 7, 1989 in Vina del Mar, Chile, where it won the award for best group at the city's annual International Song Festival. After that, Miles Joseph and the back up singers were dropped in favor of former Ted Nugent guitarist Dave Amato (who was brought aboard in May 1989) and keyboardist/songwriter/producer Jesse Harms. The 1990 release The Earth, a Small Man, His Dog and a Chicken, with Bryan Hitt (formerly of Wang Chung) on drums, was a commercial disappointment. The album produced only one, and - to date - the band's last Billboard Hot 100 single, "Love Is a Rock," which peaked at #65. Harms, disenchanted by the album's failure, left the group in early 1991. Shortly after his departure, Richrath assembled former members of the Midwestern band Vancouver to form a namesake band, Richrath. After touring for several years, the Richrath band released Only the Strong Survive in 1992 on the GNP Crescendo label. Richrath (the band) continued to perform for several years before disbanding in the late 1990s. In September 1998, Gary Richrath briefly joined REO onstage at the County Fair in Los Angeles to play on band's encore song, "157 Riverside Avenue". He then joined REO once again in Los Angeles in May 2000 for the same encore but no serious plans for a reunion ever materialized. Having lost their recording contract with Epic, REO Speedwagon ended up releasing Building the Bridge (1996) on the Priority/Rhythm Safari label. When that label went bankrupt, the album was released on Castle Records, which also experienced financial troubles. REO Speedwagon ultimately self-financed this effort, which failed to chart. The title track did make R&R's AC Top 30 chart.
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What changes were in store during the 90's?

Answer:
Harms, disenchanted by the album's failure, left the group in early 1991.

Question:
Zheng He (Chinese: Zheng He ; 1371-1433 or 1435) was a Chinese mariner, explorer, diplomat, fleet admiral, and court eunuch during China's early Ming dynasty. He was originally born as Ma He in a Muslim family, later adopted the conferred surname Zheng from Emperor Yongle. Zheng commanded expeditionary voyages to Southeast Asia, South Asia, Western Asia, and East Africa from 1405 to 1433. His larger ships stretched 120 meters or more in length.
Zheng He's sailing charts, the Mao Kun map, were published in a book entitled the Wubei Zhi (A Treatise on Armament Technology) written in 1621 and published in 1628 but traced back to Zheng He's and earlier voyages. It was originally a strip map 20.5 cm by 560 cm that could be rolled up, but was divided into 40 pages which vary in scale from 7 miles/inch in the Nanjing area to 215 miles/inch in parts of the African coast. Investigation into folios 19V to 20R of the Mao Kun Map which covers the Indian Ocean including the South India, Sri Lanka, the Maldives, and East Africa suggests that it is a composite of four maps, one for Sri Lanka, one for South India one for the Maldives and one for around 400 km of the East African coast, no further south than 6 degrees south of the Equator. Each of these maps is positioned at a different orientation to fit with the ocean currents and winds required of a sailing chart, rather than a formal map. The analysis also suggests that Arabic-speaking pilots with a detailed knowledge of the African coast were involved in the cartography. There is little attempt to provide an accurate 2-D representation; instead the sailing instructions are given using a 24-point compass system with a Chinese symbol for each point, together with a sailing time or distance, which takes account of the local currents and winds. Sometimes depth soundings are also provided. It also shows bays, estuaries, capes and islands, ports and mountains along the coast, important landmarks such as pagodas and temples, and shoal rocks. Of 300 named places outside China, more than 80% can be confidently located. There are also fifty observations of stellar altitude.
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What is the sailing charts ?

Answer:
the Mao Kun map, were published in a book entitled the Wubei Zhi (A Treatise on Armament Technology) written in 1621 and published in 1628