Soft copy - электронный
Stereo pair - стереопара
quality digital camera – камера высокого разрешения
Reflectance - отражение
active sensor – активный сенсор
Editing - редактирование
to remove – удалять, убирать
node – точка пересечения
undershoot – недостаточный подъем
overshoot – отклонение, промах
blemish – затемнение, дефект
adjacency – сопредельность, прилегание, соседство
inclusion – присоединение, инклюзия
Property - свойство
ownership – имущество, собственность
to manipulate – манипулировать, управлять
To register - регистрировать
To undergo - подвергаться
Means - средство
curved surface – искривленная поверхность
isopleth – изоплета, изолиния
contour line – контурная линия
To indicate - показывать
Shaded - затемненный
Relief - рельеф
thalweg – линия наибольших водных глубин, тальвег
containment – вместимость, объем
Proximity - близость
data set – набор данных
output – выходные данные
Overlay - наложение
input – входящие данные
to intersect – пересекать, частично совпадать
to retains – аккумулировать, вмещать, сохранять, удерживать
data extraction – извлечение данных
Clip - клип
II. Read and translate the text:
Data capture
Data capture—entering information into the system—consumes much of the time of GIS practitioners. There are a variety of methods used to enter data into a GIS where it is stored in a digital format.
Existing data printed on paper or PET film maps can be digitized or scanned to produce digital data. A digitizer produces vector data as an operator traces points, lines, and polygon boundaries from a map. Scanning a map results in raster data that could be further processed to produce vector data.
Survey data can be directly entered into a GIS from digital data collection systems on survey instruments using a technique called Coordinate Geometry (COGO). Positions from a Global Positioning System (GPS), another survey tool, can also be directly entered into a GIS.
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Remotely sensed data also plays an important role in data collection and consist of sensors attached to a platform. Sensors include cameras, digital scanners and LIDAR, while platforms usually consist of aircraft and satellites.
The majority of digital data currently comes from photo interpretation of aerial photographs. Soft copy workstations are used to digitize features directly from stereo pairs of digital photographs. These systems allow data to be captured in 2 and 3 dimensions, with elevations measured directly from a stereo pair using principles of photogrammetry. Currently, analog aerial photos are scanned before being entered into a soft copy system, but as high quality digital cameras become cheaper this step will be skipped.
Satellite remote sensing provides another important source of spatial data. Here satellites use different sensor packages to passively measure the reflectance from parts of the electromagnetic spectrum or radio waves that were sent out from an active sensor such as radar. Remote sensing collects raster data that can be further processed using different bands to identify objects and classes of interest, such as land cover.
When data is captured, the user should consider if the data should be captured with either a relative accuracy or absolute accuracy, since this could not only influence how information will be interpreted but also the cost of data capture.
In addition to collecting and entering spatial data, attribute data is also entered into a GIS. For vector data, this includes additional information about the objects represented in the system.
After entering data into a GIS, the data usually requires editing, to remove errors, or further processing. For vector data it must be made “topologically correct” before it can be used for some advanced analysis. For example, in a road network, lines must connect with nodes at an intersection. Errors such as undershoots and overshoots must also be removed. For scanned maps, blemishes on the source map may need to be removed from the resulting raster. For example, a fleck of dirt might connect two lines that should not be connected.
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