航測(cè)數(shù)字化地形圖技術(shù)設(shè)計(jì)論文-資料下載頁
2024-10-23 09:12本頁面
【導(dǎo)讀】論文題目11000航測(cè)數(shù)字化地形圖技術(shù)設(shè)計(jì)。數(shù)字?jǐn)z影測(cè)量是基于數(shù)字影像和攝影測(cè)量的基本原理應(yīng)用計(jì)算機(jī)技術(shù)數(shù)字。影像處理影像匹配模式識(shí)別等多學(xué)科的理論與方法提取所攝對(duì)像以數(shù)字方式表。達(dá)的幾何與物理信息的攝影測(cè)量學(xué)的分支學(xué)科在航空攝影測(cè)量學(xué)方面地形圖的。成圖方法已從模擬攝影測(cè)量解析攝影測(cè)量發(fā)展到目前的數(shù)字?jǐn)z影測(cè)量本次設(shè)計(jì)。通過飛機(jī)用航攝儀對(duì)測(cè)區(qū)進(jìn)行航空攝影獲得航空攝影像片全數(shù)字?jǐn)z影測(cè)量系統(tǒng)。和加密軟件在室內(nèi)進(jìn)行像片控制點(diǎn)的加密《圖式》《規(guī)范》對(duì)采集的矢量數(shù)據(jù)進(jìn)。行編輯成正式地形圖成果。關(guān)鍵詞數(shù)字?jǐn)z影測(cè)量航空攝影測(cè)量。14成圖規(guī)格及主要技術(shù)規(guī)定4. 22控制點(diǎn)的觀測(cè)與計(jì)算7. 52數(shù)字高程模型生成24. 6質(zhì)量保證措施25. 8參考文獻(xiàn)及資料27. 15℃年平均降雨960毫米年平均2160小時(shí)年平均無霜期224天。此次平面控制測(cè)量將采用GPSDE及測(cè)量D級(jí)為測(cè)區(qū)首級(jí)平面控制網(wǎng)E級(jí)為。次級(jí)平面控制網(wǎng)D級(jí)GPS網(wǎng)平均長(zhǎng)度以35KM為宜E級(jí)GPS網(wǎng)每平米公里12個(gè)埋?；蚴褂肎PS網(wǎng)高程擬合方法
【正文】 Gravimetric leveling by measuring the differences in gravity at various stations by means of a gravimeter for geodetic purposes 6 Inertial positioning system in which an inertial platform has tree mutually perpendicular axes one of which is up so that the system yields elevation as one of the outputsVertical accuracies from 15 to 50 cm in distances of 60 and 100 km respectively have been reportedThe equipment cost is extremely high and applications are restricted to very large projects where terrain weather time and access impose special constraints on traditional methods 7 GPS survey elevations are referenced to the ellipsoid but can be corrected to the datum if a sufficient number of points with datum elevations are located in the region surveyed Standard deviations in elevation differences of 0053 to 0094 m are possible under these conditions Spirit leveling The most precise method of determining elevations and most monly use method is direct leveling or spirit leveling which means measuring the vertical distance directly Differential leveling is used to determine differences in elevation between points that are remote from each other by using a surveyors level together with a graduated measuring rod For example to determine the elevations of desired point B with respect to a point of known elevation A see Figure 1 the elevation of which BM is known to be above sea level the level is set up at intermediate point between A and B and rod readings are taken at both locations as a and b respectively Then the elevation of the line of sight of the instrument being horizontal is known to be the line of sight of the instrument HA a The elevation of point B can be determined by equation HB HA a － b In addition to determining the elevation of point B the elevations of any other points lower than the line of sight and visible from the level can be determined in a similar manner But some terms should be mentioned from above a is called Backsight BS which is a rod reading taken on a point of known elevation in order to establish the elevation of the instrument line of sight b is called Foresight FS which is a rod reading taken on a turning point benchmark or temporary benchmark in order to determine its elevation HA a refers to the Height of Instrument HI which is the elevation of the line of sight through the level Owing to refraction actually the line of sight is slightly curved the effects of curvature and refraction for the horizontal distance can be reduced to a negligible amount and no correction for curvature and refraction is necessary if backsight and foresight distances are balanced in practical operation Trigonometric Leveling Trigonometric leveling is used where difficult terrain such as mountainous areas precludes the use of conventional differential leveling The modern approach is to measure the slope distance and vertical angle to the point in question Slope distance is measured using electromagic distance measurers and the vertical or zenith angle using a theodolite or the total station that integrate these two instruments into a single instrument Total stations contain builtin microprocessors that calculate and display the horizontal distance from the measured slope distance and vertical height This latter facility has resulted in trigonometrical leveling being used for a wide variety of heighting procedures including contouring The basic concept of trigonometrical leveling can be seen from Figure 2 When measuring the vertical angle α and the horizontal distance S is used then the difference in elevation hAB between ground points A and B is therefore hAB S179。tanαi – v where i is the vertical height of the measuring center of the instrument above A and v is the vertical height of the center of the target above B The vertical angles are positive for angles of elevation and negative for angles of depression The zenith angles are always positive but naturally when greater than 90176。 they will produce a negative result Trigonometrical leveling method of determining difference in elevation is limited to horizontal distance less than 300 m when moderate precision is sufficient and to proportionately shorter distances as high precision is desired For the distance beyond 300 m the effects of curvature and refraction must be considered and applied To eliminate the uncertainty in the curvature and refraction correction verticalangle observations are made at both ends of the line as close in point of time as possible This pair of observations is termed reciprocal verticalangle observation The correct difference in elevation between the two ends of the line is the mean of the two values puted both ways either with or without taking into account curvature and refractionThe important notes should be mentioned here is that surveyors used to working with spirit levels have referenced orthometric heights H to the average surface of the earth as depicted by MSL However the elevation coordinate h given by GPS solutions refers to the height from the surface of the ellipsoid to the ground statio
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