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70-510: Location information (known by the many names mentioned here) is stored in a geographic information system (GIS). There are also many different types of geodata, including vector files , raster files , geographic databases , web files, and multi-temporal data. Spatial data or spatial information is broader class of data whose geometry is relevant but it is not necessarily georeferenced , such as in computer-aided design (CAD), see geometric modeling . Geographic data and information are

140-504: A ground sample distance of 1 inch (2.54 cm) in only 12 minutes. 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 two and three dimensions, with elevations measured directly from a stereo pair using principles of photogrammetry . Analog aerial photos must be scanned before being entered into

210-409: A spatial database ; however, this is not essential to meet the definition of a GIS. In a broader sense, one may consider such a system also to include human users and support staff, procedures and workflows, the body of knowledge of relevant concepts and methods, and institutional organizations. The uncounted plural, geographic information systems , also abbreviated GIS, is the most common term for

280-409: A "real" physical location or extent. This key characteristic of GIS has begun to open new avenues of scientific inquiry and studies. While digital GIS dates to the mid-1960s, when Roger Tomlinson first coined the phrase "geographic information system", many of the geographic concepts and methods that GIS automates date back decades earlier. One of the first known instances in which spatial analysis

350-596: A GIS database, which can be grouped into three categories: primary data capture , the direct measurement phenomena in the field (e.g., remote sensing , the global positioning system ); secondary data capture , the extraction of information from existing sources that are not in a GIS form, such as paper maps, through digitization ; and data transfer , the copying of existing GIS data from external sources such as government agencies and private companies. All of these methods can consume significant time, finances, and other resources. Survey data can be directly entered into

420-567: A GIS for both kinds of abstractions mapping references: raster images and vector . Points, lines, and polygons represent vector data of mapped location attribute references. A new hybrid method of storing data is that of identifying point clouds, which combine three-dimensional points with RGB information at each point, returning a 3D color image . GIS thematic maps then are becoming more and more realistically visually descriptive of what they set out to show or determine. GIS data acquisition includes several methods for gathering spatial data into

490-551: A GIS from digital data collection systems on survey instruments using a technique called coordinate geometry (COGO). Positions from a global navigation satellite system ( GNSS ) like the Global Positioning System can also be collected and then imported into a GIS. A current trend in data collection gives users the ability to utilize field computers with the ability to edit live data using wireless connections or disconnected editing sessions. The current trend

560-478: A full suite of capabilities for entering, managing, analyzing, and visualizing geographic data, and are designed to be used on their own. Starting in the late 1990s with the emergence of the Internet , as computer network technology progressed, GIS infrastructure and data began to move to servers , providing another mechanism for providing GIS capabilities. This was facilitated by standalone software installed on

630-507: A geographic methodology in pinpointing the source of an outbreak in epidemiology. While the basic elements of topography and theme existed previously in cartography , Snow's map was unique due to his use of cartographic methods, not only to depict, but also to analyze clusters of geographically dependent phenomena. The early 20th century saw the development of photozincography , which allowed maps to be split into layers, for example one layer for vegetation and another for water. This

700-449: A map made against a local datum may not be the same as one obtained from a GPS receiver . Converting coordinates from one datum to another requires a datum transformation such as a Helmert transformation , although in certain situations a simple translation may be sufficient. In popular GIS software, data projected in latitude/longitude is often represented as a Geographic coordinate system . For example, data in latitude/longitude if

770-429: A municipal council (conseil municipal), but with very few powers. Its members are elected at municipal elections in the same way as in municipalities with more than 3,500 inhabitants. Each arrondissement council is made up of 2/3 members, elected specifically as arrondissement councillors. Council of Paris members representing the arrondissement, also sit ex officio on their local arrondissement council. For example,

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840-410: A new dimension to business intelligence termed " spatial intelligence " which, when openly delivered via intranet, democratizes access to geographic and social network data. Geospatial intelligence , based on GIS spatial analysis, has also become a key element for security. GIS as a whole can be described as conversion to a vectorial representation or to any other digitisation process. Geoprocessing

910-598: A police station. For a table giving the names of the eighty quartiers , see Quarters of Paris . On 11 October 1795, Paris was divided into twelve arrondissements. They were numbered from west to east. The numbers 1–9 were on the Right Bank of the Seine . The numbers were 10–12 on the Left Bank . Each arrondissement was subdivided into four quartiers , which corresponded to the 48 original districts created in 1790. In

980-998: A relational database containing text or numbers can relate many different tables using common key index variables, GIS can relate otherwise unrelated information by using location as the key index variable. The key is the location and/or extent in space-time. Any variable that can be located spatially, and increasingly also temporally, can be referenced using a GIS. Locations or extents in Earth space–time may be recorded as dates/times of occurrence, and x, y, and z coordinates representing, longitude , latitude , and elevation , respectively. These GIS coordinates may represent other quantified systems of temporo-spatial reference (for example, film frame number, stream gage station, highway mile-marker, surveyor benchmark, building address, street intersection, entrance gate, water depth sounding, POS or CAD drawing origin/units). Units applied to recorded temporal-spatial data can vary widely (even when using exactly

1050-502: A result of this, Tomlinson has become known as the "father of GIS", particularly for his use of overlays in promoting the spatial analysis of convergent geographic data. CGIS lasted into the 1990s and built a large digital land resource database in Canada. It was developed as a mainframe -based system in support of federal and provincial resource planning and management. Its strength was continent-wide analysis of complex datasets . The CGIS

1120-479: 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. The earth can be represented by various models, each of which may provide a different set of coordinates (e.g., latitude, longitude, elevation) for any given point on

1190-449: A scale of 1:50,000. A rating classification factor was also added to permit analysis. CGIS was an improvement over "computer mapping" applications as it provided capabilities for data storage, overlay, measurement, and digitizing /scanning. It supported a national coordinate system that spanned the continent, coded lines as arcs having a true embedded topology and it stored the attribute and locational information in separate files. As

1260-492: A server, similar to other server software such as HTTP servers and relational database management systems , enabling clients to have access to GIS data and processing tools without having to install specialized desktop software. These networks are known as distributed GIS . This strategy has been extended through the Internet and development of cloud-based GIS platforms such as ArcGIS Online and GIS-specialized software as

1330-498: A service (SAAS), and mobile computing . The distinction must be made between a singular geographic information system , which is a single installation of software and data for a particular use, along with associated hardware, staff, and institutions (e.g., the GIS for a particular city government); and GIS software , a general-purpose application program that is intended to be used in many individual geographic information systems in

1400-508: A service (SAAS). The use of the Internet to facilitate distributed GIS is known as Internet GIS . An alternative approach is the integration of some or all of these capabilities into other software or information technology architectures. One example is a spatial extension to Object-relational database software, which defines a geometry datatype so that spatial data can be stored in relational tables, and extensions to SQL for spatial analysis operations such as overlay . Another example

1470-548: A soft-copy system, for high-quality digital cameras this step is 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. The most common method of data creation

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1540-415: A specific aspect of the surface. Some of the most common include: Most of these are generated using algorithms that are discrete simplifications of vector calculus . Slope, aspect, and surface curvature in terrain analysis are all derived from neighborhood operations using elevation values of a cell's adjacent neighbours. Each of these is strongly affected by the level of detail in the terrain data, such as

1610-459: A variety of application domains. Starting in the late 1970s, many software packages have been created specifically for GIS applications. Esri's ArcGIS , which includes ArcGIS Pro and the legacy software ArcMap , currently dominates the GIS market. Other examples of GIS include Autodesk and MapInfo Professional and open-source programs such as QGIS , GRASS GIS , MapGuide , and Hadoop-GIS . These and other desktop GIS applications include

1680-406: A variety of forms, such as a collection of separate data files or a single spatially-enabled relational database . Collecting and managing these data usually constitutes the bulk of the time and financial resources of a project, far more than other aspects such as analysis and mapping. GIS uses spatio-temporal ( space-time ) location as the key index variable for all other information. Just as

1750-438: Is digitization , where a hard copy map or survey plan is transferred into a digital medium through the use of a CAD program, and geo-referencing capabilities. With the wide availability of ortho-rectified imagery (from satellites, aircraft, Helikites and UAVs), heads-up digitizing is becoming the main avenue through which geographic data is extracted. Heads-up digitizing involves the tracing of geographic data directly on top of

1820-511: Is a GIS operation used to manipulate spatial data. A typical geoprocessing operation takes an input dataset , performs an operation on that dataset, and returns the result of the operation as an output dataset. Common geoprocessing operations include geographic feature overlay, feature selection and analysis, topology processing, raster processing, and data conversion. Geoprocessing allows for definition, management, and analysis of information used to form decisions. Many geographic tasks involve

1890-653: Is a rapidly changing field, and GIS packages are increasingly including analytical tools as standard built-in facilities, as optional toolsets, as add-ins or 'analysts'. In many instances these are provided by the original software suppliers (commercial vendors or collaborative non commercial development teams), while in other cases facilities have been developed and are provided by third parties. Furthermore, many products offer software development kits (SDKs), programming languages and language support, scripting facilities and/or special interfaces for developing one's own analytical tools or variants. The increased availability has created

1960-461: 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. 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

2030-464: Is collected and stored in various ways, the two data sources may not be entirely compatible. So a GIS must be able to convert geographic data from one structure to another. In so doing, the implicit assumptions behind different ontologies and classifications require analysis. Object ontologies have gained increasing prominence as a consequence of object-oriented programming and sustained work by Barry Smith and co-workers. Spatial ETL tools provide

2100-437: Is far more precise than the machines of conventional map analysis. All geographical data are inherently inaccurate, and these inaccuracies will propagate through GIS operations in ways that are difficult to predict. Data restructuring can be performed by a GIS to convert data into different formats. For example, a GIS may be used to convert a satellite image map to a vector structure by generating lines around all cells with

2170-420: Is more commonly used, heads-down digitizing is still useful for digitizing maps of poor quality. 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. When data

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2240-467: Is necessary to distinguish between the two systems, the original arrondissements are indicated by adding the term ancienne ("former" or "old"), for example, 2ème ancienne or 7ème anc . Before the reorganization, non-married couples who lived together were said to have "married at the town hall of the 13th arrondissement" (" se marier à la mairie du 13e arrondissement "), as a jocular reference to there being no 13th. When Haussmann released his plan for

2310-445: Is no single standard for data quality, because the necessary degree of quality depends on the scale and purpose of the tasks for which it is to be used. Several elements of data quality are important to GIS data: The quality of a dataset is very dependent upon its sources, and the methods used to create it. Land surveyors have been able to provide a high level of positional accuracy utilizing high-end GPS equipment, but GPS locations on

2380-521: Is the proliferation of geospatial libraries and application programming interfaces (e.g., GDAL , Leaflet , D3.js ) that extend programming languages to enable the incorporation of GIS data and processing into custom software, including web mapping sites and location-based services in smartphones . The core of any GIS is a database that contains representations of geographic phenomena, modeling their geometry (location and shape) and their properties or attributes . A GIS database may be stored in

2450-498: Is to utilize applications available on smartphones and PDAs in the form of mobile GIS. This has been enhanced by the availability of low-cost mapping-grade GPS units with decimeter accuracy in real time. This eliminates the need to post process, import, and update the data in the office after fieldwork has been collected. This includes the ability to incorporate positions collected using a laser rangefinder . New technologies also allow users to create maps as well as analysis directly in

2520-518: The 1st . The Gobelins area became the 13th instead. In early 2016, mayor Anne Hidalgo proposed that the first four arrondissements should have their administrations merged. The Council of Paris approved this in February 2016. The four have a combined population of about 100,000, with the 1st , 2nd , 4th , and 3rd arrondissements in that order being the four smallest in Paris. In August 2016,

2590-640: The CAD  platform, Environmental Systems Research Institute ( ESRI ), CARIS  (Computer Aided Resource Information System), and ERDAS (Earth Resource Data Analysis System) emerged as commercial vendors of GIS software, successfully incorporating many of the CGIS ;features, combining the first-generation approach to separation of spatial and attribute information with a second-generation approach to organizing attribute data into database structures. In 1986, Mapping Display and Analysis System (MIDAS),

2660-426: The Internet , requiring data format and transfer standards. More recently, a growing number of free, open-source GIS packages run on a range of operating systems and can be customized to perform specific tasks. The major trend of the 21st Century has been the integration of GIS capabilities with other Information technology and Internet infrastructure, such as relational databases , cloud computing , software as

2730-482: The ordinal number corresponding to the arrondissement, e.g. "Elle habite dans le sixième", "She lives in the 6th (arrondissement)". Due to suburbanization , the population of Paris has gradually shifted outward, with only two arrondissements still growing. Uniquely among French cities, Paris is both a municipality ( commune ) and a department ( département ). Under the PLM Law ( Loi PLM ) of 1982, which redefined

2800-400: The terrain , the shape of the surface of the earth, such as hydrology , earthworks , and biogeography . Thus, terrain data is often a core dataset in a GIS, usually in the form of a raster Digital elevation model (DEM) or a Triangulated irregular network (TIN). A variety of tools are available in most GIS software for analyzing terrain, often by creating derivative datasets that represent

2870-548: The Earth's surface. The simplest model is to assume the earth is a perfect sphere. As more measurements of the earth have accumulated, the models of the earth have become more sophisticated and more accurate. In fact, there are models called datums that apply to different areas of the earth to provide increased accuracy, like North American Datum of 1983 for U.S. measurements, and the World Geodetic System for worldwide measurements. The latitude and longitude on

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2940-517: The aerial imagery instead of by the traditional method of tracing the geographic form on a separate digitizing tablet (heads-down digitizing). Heads-down digitizing, or manual digitizing, uses a special magnetic pen, or stylus, that feeds information into a computer to create an identical, digital map. Some tablets use a mouse-like tool, called a puck, instead of a stylus. The puck has a small window with cross-hairs which allows for greater precision and pinpointing map features. Though heads-up digitizing

3010-439: The average smartphone are much less accurate. Common datasets such as digital terrain and aerial imagery are available in a wide variety of levels of quality, especially spatial precision. Paper maps, which have been digitized for many years as a data source, can also be of widely varying quality. A quantitative analysis of maps brings accuracy issues into focus. The electronic and other equipment used to make measurements for GIS

3080-429: The council of the 19th arrondissement has 42 members. 28 are conseillers d'arrondissement who only sit on the arrondissement council. 14 are conseillers de Paris who also sit on the city council. At its first meeting after the elections, each arrondissement council elects its mayor. Each arrondissement is subdivided administratively into four quartiers . Paris thus has 80 quartiers administratifs , each containing

3150-455: The data processing functionality of traditional extract, transform, load  (ETL) software, but with a primary focus on the ability to manage spatial data. They provide GIS users with the ability to translate data between different standards and proprietary formats, whilst geometrically transforming the data en route. These tools can come in the form of add-ins to existing wider-purpose software such as spreadsheets . GIS spatial analysis

3220-429: The datum is the ' North American Datum of 1983' is denoted by 'GCS North American 1983'. While no digital model can be a perfect representation of the real world, it is important that GIS data be of a high quality. In keeping with the principle of homomorphism , the data must be close enough to reality so that the results of GIS procedures correctly correspond to the results of real world processes. This means that there

3290-752: The early 1960s. In 1963, the world's first true operational GIS was developed in Ottawa, Ontario , Canada, by the federal Department of Forestry and Rural Development. Developed by Roger Tomlinson , it was called the Canada Geographic Information System (CGIS) and was used to store, analyze, and manipulate data collected for the Canada Land Inventory , an effort to determine the land capability for rural Canada by mapping information about soils , agriculture, recreation, wildlife, waterfowl , forestry and land use at

3360-489: The early days of GIS: Ian McHarg 's publication Design with Nature and its map overlay method and the introduction of a street network into the U.S. Census Bureau's DIME ( Dual Independent Map Encoding ) system. The first publication detailing the use of computers to facilitate cartography was written by Waldo Tobler in 1959. Further computer hardware development spurred by nuclear weapon research led to more widespread general-purpose computer "mapping" applications by

3430-527: The field, making projects more efficient and mapping more accurate. 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 . In England in the mid-1990s, hybrid kite/balloons called helikites first pioneered the use of compact airborne digital cameras as airborne geo-information systems. Aircraft measurement software, accurate to 0.4 mm,

3500-597: The first desktop GIS product, was released for the DOS operating system. This was renamed in 1990 to MapInfo for Windows when it was ported to the Microsoft Windows platform. This began the process of moving GIS from the research department into the business environment. By the end of the 20th century, the rapid growth in various systems had been consolidated and standardized on relatively few platforms and users were beginning to explore viewing GIS data over

3570-408: The first examples of general-purpose GIS software that was not developed for a particular installation, and was very influential on future commercial software, such as Esri ARC/INFO , released in 1983. By the late 1970s two public domain GIS systems ( MOSS and GRASS GIS ) were in development, and by the early 1980s, M&S Computing (later Intergraph ) along with Bentley Systems Incorporated for

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3640-569: The form of a clockwise spiral , often likened to a snail shell , starting from the middle of the city, with the first on the Right Bank (north bank) of the Seine . In French, notably on street signs, the number is often given in Roman numerals. For example, the Eiffel Tower belongs to the VII arrondissement , while Gare de l'Est is in the X arrondissement . In daily speech, people use

3710-587: The foundation of location-enabled services, which rely on geographic analysis and visualization. GIS provides the ability to relate previously unrelated information, through the use of location as the "key index variable". Locations and extents that are found in the Earth's spacetime are able to be recorded through the date and time of occurrence, along with x, y, and z coordinates ; representing, longitude ( x ), latitude ( y ), and elevation ( z ). All Earth-based, spatial–temporal, location and extent references should be relatable to one another, and ultimately, to

3780-517: The governance of Paris, Lyon, and Marseille, hence the PLM acronym , there are both a city council called the Council of Paris , and 20 arrondissement councils in Paris. The PLM Law set limits to the prerogatives of the mayor of Paris, who has to deal with the powers granted to the prefect of police on security issues. The 20 arrondissement councils (conseils d'arrondissement) are similar in operation to

3850-747: The industry and profession concerned with these systems. It is roughly synonymous with geoinformatics . The academic discipline that studies these systems and their underlying geographic principles, may also be abbreviated as GIS, but the unambiguous GIScience is more common. GIScience is often considered a subdiscipline of geography within the branch of technical geography . Geographic information systems are utilized in multiple technologies, processes, techniques and methods. They are attached to various operations and numerous applications, that relate to: engineering, planning, management, transport/logistics, insurance, telecommunications, and business. For this reason, GIS and location intelligence applications are at

3920-500: The larger French departments . The number of the arrondissement is indicated by the last two digits in most Parisian postal codes , 75001 up to 75020. In addition to their number, each arrondissement has a name, often for a local monument. For example, the 5th arrondissement is also called "Panthéon" in reference to the eponymous building . The first four arrondissements have a shared administration, called Paris Centre . The twenty arrondissements (French: "rounding") are arranged in

3990-698: The late 1850s, Emperor Napoleon III and the Prefect of the Seine Baron Haussmann developed a plan to incorporate several of the surrounding communes into the Paris jurisdiction. In 1859, Parliament passed the necessary legislation, and the expansion took effect when the law was promulgated on 3 November 1859. City taxes were extended to the new neighborhoods in July 1860. The previous twelve arrondissements were done away with, and twenty new arrondissements were created . In historical records, when it

4060-484: The layers were finished, they were combined into one image using a large process camera. Once color printing came in, the layers idea was also used for creating separate printing plates for each color. While the use of layers much later became one of the typical features of a contemporary GIS, the photographic process just described is not considered a GIS in itself – as the maps were just images with no database to link them to. Two additional developments are notable in

4130-486: The matter was taken up in the National Assembly , and approved in February 2017. In October 2018, in a postal referendum, the town hall of the 3rd arrondissement was chosen to house the new shared administration. The name " Paris Centre " was chosen for the sector. In June 2020, the reform was implemented, the day after the second round of the 2020 Paris municipal election . The four arrondissements now share

4200-579: The new boundaries and numbering system, residents of Passy objected because it placed them in the new 13th arrondissement. The mayor of Passy, Jean-Frédéric Possoz, devised the numbering of the arrondissements in a spiral pattern, beginning on the Right Bank, which put Passy in the 16th . This system turned the Louvre area, which contained the Tuileries Palace and other imperial palaces, into

4270-663: The real world, such as roads, land use, elevation, trees, waterways, and states. The most common types of phenomena that are represented in data can be divided into two conceptualizations: discrete objects (e.g., a house, a road) and continuous fields (e.g., rainfall amount or population density). Other types of geographic phenomena, such as events (e.g., location of World War II battles), processes (e.g., extent of suburbanization ), and masses (e.g., types of soil in an area) are represented less commonly or indirectly, or are modeled in analysis procedures rather than data. Traditionally, there are two broad methods used to store data in

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4340-643: The resolution of a DEM, which should be chosen carefully. Distance is a key part of solving many geographic tasks, usually due to the friction of distance . Thus, a wide variety of analysis tools have analyze distance in some form, such as buffers , Voronoi or Thiessen polygons , Cost distance analysis , and network analysis . Arrondissements of Paris The City of Paris is divided into twenty arrondissements municipaux , administrative districts, referred to as arrondissements ( pronounced [aʁɔ̃dismɑ̃] ). These are not to be confused with departmental arrondissements , which subdivide

4410-414: The same classification, while determining the cell spatial relationships, such as adjacency or inclusion. More advanced data processing can occur with image processing , a technique developed in the late 1960s by NASA and the private sector to provide contrast enhancement, false color rendering and a variety of other techniques including use of two dimensional Fourier transforms . Since digital data

4480-622: The same data, see map projections ), but all Earth-based spatial–temporal location and extent references should, ideally, be relatable to one another and ultimately to a "real" physical location or extent in space–time. Related by accurate spatial information, an incredible variety of real-world and projected past or future data can be analyzed, interpreted and represented. This key characteristic of GIS has begun to open new avenues of scientific inquiry into behaviors and patterns of real-world information that previously had not been systematically correlated . GIS data represents phenomena that exist in

4550-590: The subject of a number of overlapping fields of study , mainly: "Geospatial technology" may refer to any of "geomatics", "geomatics", or "geographic information technology." The above is in addition to other related fields, such as: This geography -related article is a stub . You can help Misplaced Pages by expanding it . Geographic information system A geographic information system ( GIS ) consists of integrated computer hardware and software that store, manage, analyze , edit, output, and visualize geographic data . Much of this often happens within

4620-460: Was able to determine the source of a cholera outbreak in London through the use of spatial analysis. Snow achieved this through plotting the residence of each casualty on a map of the area, as well as the nearby water sources. Once these points were marked, he was able to identify the water source within the cluster that was responsible for the outbreak. This was one of the earliest successful uses of

4690-608: Was never available commercially. In 1964, Howard T. Fisher formed the Laboratory for Computer Graphics and Spatial Analysis at the Harvard Graduate School of Design (LCGSA 1965–1991), where a number of important theoretical concepts in spatial data handling were developed, and which by the 1970s had distributed seminal software code and systems, such as SYMAP, GRID, and ODYSSEY, to universities, research centers and corporations worldwide. These programs were

4760-411: Was particularly used for printing contours – drawing these was a labour-intensive task but having them on a separate layer meant they could be worked on without the other layers to confuse the draughtsman . This work was initially drawn on glass plates, but later plastic film was introduced, with the advantages of being lighter, using less storage space and being less brittle, among others. When all

4830-547: Was used came from the field of epidemiology in the Rapport sur la marche et les effets du choléra dans Paris et le département de la Seine (1832). French cartographer and geographer Charles Picquet created a map outlining the forty-eight districts in Paris , using halftone color gradients, to provide a visual representation for the number of reported deaths due to cholera per every 1,000 inhabitants. In 1854, John Snow , an epidemiologist and physician,

4900-460: Was used to link the photographs and measure the ground. Helikites are inexpensive and gather more accurate data than aircraft. Helikites can be used over roads, railways and towns where unmanned aerial vehicles (UAVs) are banned. Recently aerial data collection has become more accessible with miniature UAVs and drones. For example, the Aeryon Scout was used to map a 50-acre area with

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