新华字典（第13版） vs KOURAKU

【全新修订，内容权威】 收录单字13,000余个，新增反映时代发展的新词新义 商务印书馆出版，中国社会科学院语言研究所编修 符合国家语言文字规范，内容准确可靠 【纸数对照，一键切换】 数字版与第13版纸质书内容实时对照 支持纸质书扫码联动，纸书与App无缝衔接 【多种查字方式】 一框式智能检索：拼音、部首、笔画、四角号码、词语 语音输入：说话就能查 手写输入：屏幕手写识别 摄像头取字：拍照识别查字 【标准发音，即时跟读】 知名播音员标准播读 支持即时跟读对比，矫正发音 【笔顺动画，规范书写】 动态/静态标准笔顺动画演示 支持屏幕跟写，掌握正确笔顺 【实用工具，便捷高效】 生字本：收藏疑难字，随时复习 查询历史：快速回溯 云端同步：换设备不丢失数据

KOURAKU is a visual education app about how people cross the sea and work out where they are — the science of navigation and positioning — learned by watching and interacting. Follow the story from classical celestial navigation to modern GPS through simulations and hands-on challenges. As the navigation module of the "Raku" series, KOURAKU sits next to KAIRAKU (oceanography). If KAIRAKU is the science of tides and currents, KOURAKU is the craft of using them to cross the ocean. It covers six topics from high-school earth science and physics up to introductory navigation. [Explore and Challenge — a learning cycle] Every mode can be used in two ways: - Explore: move the sliders freely and see the principle at work. - Challenge: solve a task with the answer hidden. Read the instrument to measure, work out your position, then check your answer. When you get it right, the app shows the reasoning step by step. Each mode has 5 stages, for 30 stages across the 6 modes. Cleared stages are recorded in the Logbook on the home screen, so you can see your progress at a glance. [Six Modes] - Celestial Latitude Measure a body's altitude with a sextant and find your latitude. The altitude of Polaris equals your latitude, and from the noon Sun you get latitude = 90° − altitude + declination. In the challenges, line the sextant up with the star or the Sun, read the altitude, and give the ship's latitude. - Longitude & Chronometer Longitude comes from the time difference between local noon and Greenwich time. The Earth turns 15° every hour, so a clock running ahead or behind tells you how far east or west you are. See why a marine chronometer that keeps accurate time at sea made longitude measurable. - Dead Reckoning Build up course and speed over time to estimate your position. Add a current and watch the estimated position drift away from the true one. Challenges range from distance run to choosing a course that allows for the current. - Chart & Compass Correct a compass course for deviation and variation to get the true course (add East, subtract West). Then try the reverse: from a true course on the chart, find the compass course to steer. - Tides The sea rises and falls with the Moon and Sun: spring tides around new and full moon, neap tides around the quarters. Read the times and heights of high and low water from a 24-hour tide curve, and work out when a ship can safely cross a shallow channel. - GPS Positioning Find your position from the distances to several satellites (trilateration). Turn signal travel time into range, see how a tiny receiver clock error throws the fix far off, and how a fourth satellite solves that error. [Features] - 30 challenge stages: 6 modes × 5 stages - A Logbook that records cleared stages (clear it any time) - Principle / explanation sheet in every mode - A one-line "how to try" guide on every screen - A journey through time from classical navigation to modern GPS - 9 languages (Japanese, English, Chinese Simplified/Traditional, Spanish, Portuguese (BR), Korean, German, French) - Supports landscape, large text sizes, and VoiceOver - Difficulty labels (Beginner, Standard, Advanced), a "Start here" mark and a start button on Home show where to begin - Nautical chart and logbook visuals, with dark / light themes - About screen with links to the privacy policy and support - Free to use with every feature unlocked (banner ads only; no in-app purchases or subscriptions) [Recommended for] - Students of earth science, physics, navigation, or positioning - Anyone who wants an intuitive feel for celestial navigation, longitude, and dead reckoning - People interested in the sea, ships, and geography - Teachers looking for classroom material - Anyone curious about how GPS actually works out where you are Note: This app uses simplified simulations for education. Do not use it for real navigation or positioning.