How modern maps are created in geography 5. Modern methods of creating maps. Geographical characteristics of the territories

Long gone are the days when it was enough to indicate the address and phone number on the contact page. Today, any company that values ​​its customers must place a location map next to the address. This is very convenient, including in terms of UX. You can create a simple location map using the Yandex.Maps constructor or Google Map. But sometimes something more complicated is required - for example, a map may be needed for a presentation or for creating infographics. In this case, you can use special online tools to create custom maps. Some of these tools allow you to create interactive maps that present information in the most user-friendly way. FreelanceToday brings you 10 free map creation tools.

The Animaps service extends the functionality of Google Maps by allowing you to create maps with animated markers. Markers move around the map, showing, for example, the route of movement. A very useful service for creating interactive infographics. With the help of Animaps, you can create a whole story about any event, accompanied by text blocks and illustrations.

The easy-to-use Scribble Maps service has many tools for creating almost any kind of map. You can make a regular route map, but at the same time, the service can be useful for designers who would like to create colorful infographics. Scribble Maps has the ability to add text, images, draw and paint over various geometric shapes, place markers, and much more. If you need a map-based infographic, there is no better tool. The finished map can be posted on a website, blog, or sent to a client, saving it in PDF format.

The creators of the MapTiler service made sure that the maps created by the user are displayed on any device. MapTiler is one of the most convenient applications for preparing tiles using the Google Maps API. Unfortunately, the free version of the program has very limited functionality, with which you can create only the most basic maps.

HeatmapTool is the best online service for creating very accurate heat maps. With the help of such a map, you can quickly visualize data using different colors. The service allows you to control the radius, scaling and opacity of heat spots. Information can be updated in real time. Why was this service created? First of all, for the visual display of any statistical data in a pre-selected region. You can make fairly complex maps, for example, using the service, you can show the coverage of the cellular network, the population density in the country, and much more. The service is very powerful, with its help you can quickly process even very large amounts of statistical data.

Since buying Nokia, Microsoft has significantly improved its Bing Maps mapping service. Nokia maps have always been highly detailed and have good coverage, so you don't have to worry about accuracy. The functionality of the service cannot boast of diversity, but tracks, markers and geometric shapes are enough to create a fairly informative map. It is also possible to add images and text comments. After the work is completed, the result must be saved, after which Bing Maps will generate a link and code for embedding the map on the site.

The friendly user interface of the Click2Map service will help you quickly and easily create interactive maps of any complexity. The powerful functionality of the service will allow you to create professional maps in the shortest possible time. With the help of a large set of icons, you can personalize the map if you want to talk about a particular field of activity. Thematic markers will allow users to easily navigate the map. Markers can also be used to locate a particular point. The marker supports various types of content - text, images, HTML code. To get access to all the features of the service, you will have to subscribe to a paid subscription, however, if you register a free account, you can create maps with a limited number of markers, a maximum of 10.

Mapping service ZeeMaps makes it easy to create, publish and share interactive maps. The service works on the basis of Google Map and with its help you can create even a very complex map with a lot of data. Statistics can be imported from Excel, Access, MS Outlook and other programs. There are no restrictions on the number of markers, information can be changed at any time at the request of the user. You can add pictures, text, audio files, and YouTube videos to markers.

The UMapper application allows you to create embedded flash cards. The UMapper visual editor is intuitive and can be used to add markers, draw shapes, and add interactive elements to the map. The service takes map data from Microsoft Virtual Earth, Google, Yahoo, OpenStreet, which makes it truly universal. With the help of the application, you can even earn money - if the created card receives 50 thousand views in a month, the service will transfer $12.50 to the user's account. The disadvantages of UMapper include a watermark that appears on the map when using free version and showing embedded advertisements on the map.

GmapGis is a simple online application for drawing on Google maps. You can place markers, measure the distance between two points on the map, draw lines and geometric shapes. All the functionality is presented at the top of the page, so there will be no problems using the service - everything is very clear. The result can be saved as a file or as a link. When using GmapGIS, a problem may occur - the user cannot draw a line or draw a shape. In this case, the developers recommend closing and reopening the browser. After that, you will have full access to all functionality.

For 10 years now, digital photogrammetry methods implemented in digital photogrammetric stations (DFS) have been widely used in the production enterprises of Roskartografiya to create and update digital maps and plans, to obtain other types of products based on aerospace materials. An important milestone in the introduction of digital methods into production was the instruction of the head of Roskartografiya on February 19, 2001 on the priority use of CFS in industry enterprises. The document required all technical projects to be submitted for options for creating and updating digital maps and plans for the CFS.
The development of TsFS began at TsNIIGAiK together with the State Scientific and Production Enterprise "Geosystem" (Ukraine) in 1995, and its first production introduction - in 1997. One of the first enterprises in the industry that most successfully introduced this development and made a significant contribution to the development of new methods and the provision assistance in their finalization were BaltAGP, NovgorodAGP, YuzhAGP. To date, more than 1000 digital stations are used in the industry, which allows us to consider them the basic technical tool that solves all the main tasks of topographic mapping, including the creation, updating and generalization of the DTC of the entire large-scale range of aerospace images, obtaining orthophotomaps and photo maps, preparing digital publishing originals and receiving other products. The information support of the created digital maps meets the requirements of Roskartografiya and the VTU of the General Staff of the Ministry of Defense of the Russian Federation, which makes it possible to obtain a regulatory product for conversion into other topographic and geographic information systems.
2. Automation of technological processes
DFS, in comparison with previously used methods, makes it possible to automate a number of labor-intensive and routine processes in the technologies for creating and updating digital topographic maps (DTC) and plans (DTC), including:
- Automatic recovery stereo models based on the results of photogrammetric network adjustment;
- Automatic formation and graphic display of objects using cartographic templates for the entire scale range;
- Automation of quality control processes for created maps;
- Automatic identification of points at the stages of internal, relative and external orientation of images of the photogrammetric block and a separate stereopair;
- Automatic construction of DTM on a regular or irregular grid;
- Automatic construction of contour lines with a given relief section;
- Automatic construction of additional horizontals according to the existing ones with an intermediate height of the relief section;
- Automatic construction of DEM along horizontal lines;
- Automatic creation of an orthophoto image per block;
- Automatic loading of the next processed image (stereo pair) during object stereo rendering;
- Stereoscopic collection of contours and pickets in the mode of automatic stereo identification.
3. Improvement of technology and software
3.1. Photogrammetric thickening
The technology of photogrammetric thickening of the survey substantiation ensures the implementation of digital phototriangulation in real time, i.e. in the process of measuring tie points, the received data is adjusted with control of the adjustment results. This allows you to localize and quickly eliminate possible measurement errors, preventing their accumulation. To implement the on-line technology, the well-known software package Fotocom, developed by Doctor of Technical Sciences, is integrated into the CFS software. I.T. Antipov. A feature of the condensation technology is the possibility of simultaneously displaying on the monitor screen all adjacent images with the image of the measured point of the network. This approach makes it possible to more fully use the methods of automatic identification of points of the same name on all overlapping images and to visually control possible errors.
The elements of external orientation of images obtained as a result of photogrammetric thickening are used in subsequent processes of their processing (DEM, orthophoto, mapping). The latest improvements in technology and software relate to the drafting of a triangulation block for digital block layout, the construction of a single block large sizes on several pre-measured and adjusted adjacent blocks, automating the processes of stereoscopic control of the adjustment results, building a block on a flight that has gaps in images, “holes” inside the block. Software has been developed for obtaining photo outlines and coordinates of control points in formats agreed with the storage bank.
3.2. Obtaining a digital elevation model
The technology for obtaining digital information about the relief for orthorectification, creating the high-rise part of the DTC and CTP is based on stereoscopic image processing. Stereoscopic terrain collection uses automated, interactive, or manual
modes, or combinations thereof.

At the Massachusetts Museum of Modern Art

It is much easier for modern cartographers than their colleagues from the past, who created a map far from ideal with very approximate calculations of the location of objects. Until the beginning of the 20th century, cartography changed slowly and, although there were almost no white spots left by that time, they could not boast of the accuracy of the map.

With the beginning of the era of aerial survey of the terrain, cartographers received an excellent tool that made it possible to draw up a detailed plan of any territory. Satellite imagery was supposed to complete a millennium of work to create the perfect orientation tool, but cartographers faced new challenges.

As a tool for solving cartographic problems and errors, the OpenStreetMap (OSM) project appeared, on the basis of which our MAPS.ME service exists. There is a huge amount of data in OSM: not only outlined satellite imagery but also information that only the locals know. Today we will tell you in more detail how the real world is digitized and becomes a map.

Photofixation of the area

This map is 14,000 years old

The first maps appeared in the period primitive history. Bends of rivers, ridges, ravines, rocky peaks, animal trails - all objects were indicated by simple notches, wavy and straight lines. Subsequent maps did not go far from the first schematic drawings.
The invention of the compass, the telescope, the sextant, and other instruments of maritime navigation, and the period of great geographical discoveries that followed, led to the flourishing of cartography, but the maps were still not accurate enough. The use of various instruments and mathematical methods could not be a solution to the problem - after all, maps were drawn by a person using descriptions or diagrams created in nature.

A new stage in the development of cartography began with topographic surveys. For the first time, ground surveys for the preparation of topographic maps began to be carried out in the 16th century, and the first aerial topographic surveys of hard-to-reach areas were carried out in the 1910s. In Russia, both cadastral and notorious "general staff maps", the accuracy and coverage of which at that time turned out to be unprecedented, were created by topographers with the help of.

An example of decryption from the middle of the last century

After aerial photography, a long and difficult stage of deciphering is necessary. Objects in the image need to be identified and recognized, their qualitative and quantitative characteristics should be established, and the results recorded. The decryption method is based on the patterns of photographic reproduction of the optical and geometric properties of objects, as well as on the relationship of their spatial distribution. Simply put, three factors are taken into account: optics, image geometry, and spatial placement.

To obtain relief data, contour-combined and stereotopographic methods are used. In the first method, directly on the ground with the help of geodetic instruments, the heights of the most important points on the surface are determined and then the position of contour lines is plotted on aerial photographs. The stereotopographic method involves the partial overlapping of two images with each other in such a way that each of them depicts the same area of ​​the terrain. In a stereoscope, this area looks like a three-dimensional image. Further, according to this model, with the help of instruments, the heights of the points of the terrain are determined.

satellite imagery

An example of a stereo pair from a satellite

Satellites also work in a similar way, creating a stereo image. Terrain information (and many other data, including radar interferometry - building digital terrain models, determining displacements and deformations earth's surface and facilities) provide radar and optical Earth remote sensing satellites.

Ultra-high resolution satellites do not photograph everything in a row (endless Siberian forests are not needed in high resolution), but by order for a certain territory. Such satellites include, for example, Sentinel (there are Sentinel-1 in orbit, which is responsible for radar surveys, Sentinel-2, which conducts optical surveys of the Earth's surface and study vegetation, and Sentinel-3, which monitors the state of the world's oceans).

Image of Los Angeles, satellite Landsat 8

Satellites send data not only in the visible spectrum, but also in the infrared (and a few others). Data from spectral bands invisible to the human eye allow you to analyze surface types, monitor crop growth, detect fires and much more.

The Los Angeles image includes frequency bands of the electromagnetic spectrum corresponding (in Landsat 8 terminology) to the 4-3-2 bands. Landsat designates the red, green, and blue sensors as 4, 3, and 2, respectively. A full color image appears when the image from these sensors is combined.

The data is received and processed by satellite owners and official distributors - DigitalGlobe, e-Geos, Airbus Defense and Space and others. In our country, the main suppliers of satellite images are "", "" and "".

Many services are built on the basis of sets Global data Land Survey (GLS) from the US Geological Survey (USGS) and NASA. The GLS receives data primarily from the Landsat project, which has been creating real-time satellite imagery of the entire planet since 1972. With the help of Landsat, you can get information about the entire earth's surface, as well as about its changes over the past decades. It is this project that remains the main source of Earth remote sensing data on small scales for all public mapping services.

in terms of MODIS

The scanning spectroradiometer of medium resolution MODIS (MODerate-resolution Imaging Spectroradiometer) is located on the Terra and Aqua satellites, which are part of the NASA EOS (Earth Observing System) integrated program. The resolution of the resulting images is coarser than most other satellites, but the coverage allows for a daily global collection of images in near real time. Multispectral data are useful for analyzing the earth's surface, the ocean and the atmosphere, making it possible to study changes in clouds, snow, ice, water bodies, the state of vegetation, track the dynamics of floods, fires, etc. on-line (literally in a few hours).

In addition to satellites, there is another promising direction of "vertical" shooting - obtaining data from drones. So the company sends drones (rarely - quadcopters) to film farmlands - it turns out more economical than using a satellite or a plane.

Satellites provide a huge variety of information and can photograph the entire Earth, but companies order data only for the territory they need. Due to the high cost of satellite imagery, companies prefer to detail the territories of large cities. Everything that is considered to be a sparsely populated area is usually filmed in the most in general terms. In regions with constant cloudiness, satellites take more and more pictures, achieving a clear image and increasing costs. However, some IT companies can afford to buy images from entire countries. For example, Bing Maps.

Based on satellite images and measurements on the ground, vector maps are created. The processed vector data is sold to companies that print paper maps and/or create map services. Drawing maps on your own from satellite images is expensive, so many companies prefer to buy a ready-made solution based on the Google Maps API or Mapbox SDK and finalize it with their own staff of cartographers.

Satellite map problems

In the simplest case, to draw a modern map, it is enough to take a satellite image or its fragment and redraw all objects in the editor or in some online interactive map creator service. At first glance, in the example above from OSM, everything is fine - the roads look like they should look. But this is only at first glance. In fact, these figures do not correspond real world, since they are distorted and shifted relative to the real location of objects.

The satellite takes pictures at an angle at high speed, the time of taking pictures is limited, the pictures stick together ... Errors overlap each other, so to create maps they began to use photo and video shooting on the ground, as well as geo-tracking of cars, which is an obvious proof of the existence of a certain route.

An example of an image in which a problem arose due to poor orthorectification: the tracks lay perfectly near the water, but on the mountain on the right they moved out

Terrain, shooting conditions, and camera type affect the appearance of distortion in pictures. The process of eliminating distortions and converting the original image into an orthogonal projection, that is, one in which each point of the terrain is observed strictly vertically, is called orthorectification.

Redistribution of pixels in the image as a result

It is costly to use a satellite that would only shoot over a given point, so shooting is done at an angle that can reach 45 degrees. From a height of hundreds of kilometers, this leads to significant distortions. To create accurate maps, good orthorectification is vital.

Maps quickly lose relevance. Have you opened a new car park? Did you build a bypass? Has the store moved to a different address? In all these cases, outdated images of the territory become useless. Not to mention the fact that many important details, whether it be a ford on a river or a path in the forest, are not visible in images from space. Therefore, work on maps is a process in which it is impossible to put a final point.

How OpenStreetMap maps are made

The map maker on a satellite image first draws roads using track data. Since the tracks describe the movement in geographic coordinates, it is easy to determine exactly where the road passes. Then all other objects are applied. Missing and areal objects are created from images, and captions indicating the belonging of objects or supplementing them background information, are taken from observations or registers.

To create a map filled with various information, use geographic information system(GIS), designed to work with geodata - for their analysis, transformation, analytics and printing. With GIS, you can create your own map with visualization of any data. In GIS for maps, you can add Rosstat data, municipalities, ministries, departments - all so-called geospatial data.

Where does geodata come from

So, satellite images are shifted relative to reality by several tens of meters. To make a really accurate map, you need to arm yourself with a navigator (GPS receiver) or a regular phone. And then, using the receiver or the application on the phone, record the maximum number of track points. Recording is carried out along linear objects located on the ground - rivers and canals, paths, bridges, railway and tram tracks, etc. are suitable.

One track is never enough for any section - they themselves are also recorded with a certain level of error. Subsequently, the satellite background is aligned with multiple tracks recorded at different times. Any other information is taken from open sources (or donated by the data provider).

It's hard to imagine maps without information about various companies. Yelp, TripAdvisor, Foursquare, 2GIS and others collect local data about organizations with reference to GPS position. The community (including directly representatives of local businesses) independently contributes data to OpenStreetMap and Google Maps. Not all large networks want to bother with adding information themselves, so they turn to companies (, and others) to help place branches on maps and keep the data up to date.

Sometimes information about real terrain objects is added to maps through mobile applications - right away, in the field, a person has the opportunity to accurately update cartographic data. MAPS.ME has a built-in map editor for this, through which the updated data is sent directly to the OpenStreetMap database. The reliability of the information is checked by other members of the OSM community. On the other hand, data from OSM enters MAPS.ME in a raw form. Before appearing on the user's smartphone screen, they are processed and packaged.

The Future: Neural Network Cartographers

Geographical characteristic territories

Comprehensive geographical description of its area.

When answering this question, you should adhere to the following plan:

1. Geographical position territory. The area of ​​the land. Borders. The natural "framework" of the territory (the main natural objects). EGP of the territory. Socio-economic "framework" of the territory (cities and main transport routes).

2. History of territory development. Stages of development of the territory. Pioneers, explorers, explorers. Toponymy.

3. Natural resource potential of the territory. Natural conditions and resources. territorial combinations. Landscapes. Grade natural conditions and resources for the needs of the economy.

4. Population. Demographic situation. Migrations. Urbanization. Composition, structure. Peoples. Languages. Religions. Resettlement.

5. Household. Industry. Agriculture. Transport. Branches of specialization. Participation in the geographical division of labor.

6. Problems of territory development: environmental, demographic, social, etc.

Modern cartography for last years has undergone significant changes in

technologies for creating topographic maps. At present, the main products

enterprises of Roskartography became digital,

electronic cards, geoinformation systems, orthophotomaps, orthophotomaps.

An orthophoto combined with a digital topographic map enhances the visual

perception of topographic information as a whole, it is valuable for those who need

spatial information according to the nature of its activity and at the same time it is not

topographer (cartographer), it is difficult for him to perceive the conventional topographic signs of maps

and plans. The creation of new products requires a combination of traditional methods of creation

topographic maps with new, modern methods.

Along with field work (measurements), remote

earth sounding methods. Aerial photography: black and white, color, spectrozonal and

thermal imaging; satellite imagery of the earth's surface various zones spectrum.

The use of remote sensing methods allows you to quickly cover

large areas of the earth's surface (including hard-to-reach) and receive

necessary information about all objects, as well as in the presence of modern hardware and

software systems to carry out high-precision measurements on these materials.

On this moment in the center "Sevzapgeoinform" several methods

creating a digital foundation:

According to PCM (initial cartographic materials) - DPC are scanned (transparencies

permanent storage, from which cartographic factories produce printed

“ARM-RASTR2” a digital map is being created. This technology is good because it can

vectorize more than half of the content of the map in automatic mode. DPH is

dismemberment according to the content of the map (relief, hydrography, forest filling and hydrography,

contour, combination). The technology is acceptable for medium scales (1:10,000 - 1:1,000,000).

Based on ground surveys: tacheometric survey, sometimes even scale survey. This,

usually not large areas of filming. Sometimes it is advisable to shoot

a large closed area of ​​the terrain in a field way, and then on a VIDAR-type scanner,

allowing to scan cartographic materials on a rigid basis up to 13.5 mm,

we scan these ground survey materials, bind the rasters and vectorize them.

At the Sevzapgeoinform center today, one of the main methods for creating a topographic

maps, including the digital topographic map, is a stereotopographic

method. The map is created from scratch, as well as actualization (updating). Those. minimum field

works, maximum office work, which reduces the cost and shortens the cycle of creating

topographic map.

Now our Center has a modern technical base that meets the high

world standards, and allows you to create digital topographic maps with high

accuracy and in a short time. We have: RC30 - aerial photography camera with high

lens resolution (average weighted 110 lines per millimeter); PAV30-

gyro-stabilizing platform that corrects the pitch, roll and drift angles of the aircraft during

time of aerial photography; ASCOT - hardware-software control complex

flight and obtaining the coordinates of photography centers using GPS satellites;

Flykin Suite+ - GPS data post-processing software; ORIMA - adjustment program

photogrammetric measurements using the coordinates of the centers of photography from

GPS definitions; DSW500 is a photogrammetric scanner that allows you to scan

photographic image with a resolution of 5 microns; SD2000 - analytical photogrammetric

station. All of the above equipment is made in Switzerland (company

To create digital topographic maps, we use digital

photogrammetric complexes, such as "PHOTOMOD" and "CFS" created

Russian developers, allowing to perform a complex of photogrammetric

works (including the creation of orthophotomaps) directly on the computer using

stereo glasses or stereo attachments.

The process of creating a topographic base with a stereotopographic

● Field work on planned and high-altitude preparation of aerial photography. Marking

identification marks before performing aerial photography (at a minimum). If the area

upcoming work abounds in many contours, and these contours can be determined

on aerial photographs with an accuracy of 0.1 mm on the scale of the created map, then planned

altitude referencing can be performed based on the materials of an already completed

aerial photography.

● Aerial photography with the determination of the coordinates of the centers of photography (using

software and hardware complex ASCOT).

● Mandatory integral part technologies for creating topographic plans

stereotopographic method is the decoding of photographic

image, which consists in recognizing objects of the terrain or a picture,

establishing their characteristics. Decoding can be field and cameral.

More often in a combination of field and cameral, depending on the topographic

knowledge of the survey area and the accepted technological scheme of work

deciphering is done before cameral or after it.

● Scanning aerial photographs with parameters that satisfy the accuracy

topographic base.

● Direct creation of the basis of a digital topographic map

stereotopographic method at photogrammetric stations.

● Converting the digital basis into the Customer's software product and bringing

digital topographic map to the requirements of GOSTs, OSTs, regulatory

technical documents, the Customer.

● Writing a specific GIS using a newly created (up-to-date)

digital topographic map.

● Transfer of products to the Customer.

Directly in “PHOTOMOD” the Center performed a large amount of work on creating

a digital map at a scale of 1:25,000 over an area of ​​23,000 km² at the Taimyr site. Was

the whole complex of works was carried out: phototriangulation, adjustment, building a digital

terrain models and creation of orthophoto maps. In the same year, we begin to create

digital maps and orthophoto maps in the same software package already on the area of ​​50,000

The technology of work at this facility was as follows:

1. Scanning transparencies. (previously from aero negatives were printed

transparencies).

2. Photogrammetric thickening of the reference network.

3. Building a digital terrain model.

4. Creation of orthomosaic by single stereopairs.

5. Stitching orthophotomaps from single stereopairs into a trapezoid of the state layout

in scale according to the technical specifications.

6. Deciphering orthophotomaps and creating digital maps.

7. Stitching individual nomenclatures of digital maps into a single digital field.

The transparencies were scanned using a Mustek Paragon A3 PRO scanner, with

1200 dpi resolution. To correct geometric distortions introduced

printing scanner, the scanned file was processed by the ScanCorrect program

(development of the company "Rakurs"). Then, in the AT module (Photomod system),

photogrammetric thickening of the reference network. Next, we imported into the StereoDraw module

relief (horizontals that were digitized earlier according to old topographic maps),

in stereo mode, we checked whether the old relief “sits” on the surface of the model, if in any

sometimes there were changes in the relief, sometimes the stereoscopic horizontals were corrected.

The relief was converted from the StereoDraw module into the DTM module in the form of breaklines and

built a digital terrain model, and using it an orthophotomap of each stereopair and

“thrown” into the VectOr module. In the VectOr module, individual stereopairs were merged into

single trapezoid scales 1:25,000, 1:50,000 and 1:100,000, state layout. By

image of orthomosaics in the ArcView program using the field and

cameral interpretation, digital topographic maps were created

scale 1: 25,000.

Within 6 months in the Photomod system (this time includes training to work in the system)

The center has processed, up to the receipt of trapezoidal orthophotomaps, about 700

aerial photographs - this indicates that this system is quite efficient.

In the course of work in the Photomod system, we had several wishes for improvement

Photomod systems and if the company “Rakurs”, as it seems to us, will take them into account, then Photomod will only

will win and further strengthen its position in the photogrammetric processing market

aerial photography materials.

Mankind has always needed cards. Hundreds of years ago, navigators and travelers already plotted the location of the continents, most of the islands, major rivers and mountains. By the beginning of the 20th century, there were practically no “white” places on the world map, but still, the accuracy of the location of most objects left much to be desired.

This is what maps looked like in the 16th century: trip around the world Francis Drake, pay attention to the outlines of the continents

A new round in the development of cartography appeared due to the possibility of aerial photography of the terrain, and later satellite systems. Finally, people were able to solve the thousand-year-old problem - the creation of an ideal orientation object with maximum accuracy. But even then the problems were not over.

It was necessary to create a tool that could process not only satellite images, but also information that, for example, only local residents can know. This is how the OpenStreetMap (OSM) and Wikimapia services appeared. Let's discuss in more detail how the real world is digitized and becomes a map.

Location fixation

The first cards appeared thousands of years ago. Of course, these were unusual maps in the modern sense, but rather schemes, where straight and wavy lines depicted the bends of the rivers of the seas, the tops of the mountains, etc. Recently, a similar schematic map of the districts of Madrid was found, about 14 thousand years old.

Later, a compass, a telescope, a sextant and other navigational instruments were invented, which, during the period of the Great geographical discoveries, made it possible to study on a large scale and put on paper thousands of geographical objects. A striking example of this is the map of Juan de la Cosa, dated 1500. It is the middle of the last millennium that is considered to be the heyday of cartography. Around that time, basic map projections were invented, mathematical methods and principles of building maps. But still, this was not enough to create accurate maps.

Map of Juan de la Cosa, 1500. It already has the outlines of the New World

A new stage in cartography began with a topographic ground survey of the terrain, and later with aerial surveys. The first photographs of hard-to-reach areas were taken from an aircraft in 1910. Aerial photography of the area is followed by a complex process of image decoding. Each object must be recognized, qualitative and quantitative characteristics identified, and then the results recorded. Simply put, there are three fundamental factors to consider: the optics of the image, its geometry, and placement in space.

Next comes the stage of creating the terrain. For this, the contour-combined and stereotopographic methods are used. At the first, with the help of geodetic instruments, the main heights of the terrain are determined and then the contour lines of geographical objects are plotted on the images. In the second method, two images are superimposed on each other in such a way as to obtain a semblance of a three-dimensional image of the terrain, and then control heights are determined using instruments.

The advent of aerial photography in the 20th century made it possible to create more accurate maps and take into account the terrain.

satellite imagery

Nowadays, ground-based and aerial photography is becoming less and less, and they have been replaced by satellites for remote sensing of the Earth. Satellite images offer modern cartographers much more wide range opportunities. In addition to terrain data, satellite images help build stereo images, create digital terrain models, determine the displacement and deformation of objects, and so on.

Satellites can be conditionally divided into ordinary and ultra-high resolution. Naturally, photographing the taiga or the ocean does not require very high-quality photographs, and for certain territories or tasks, satellites photographing in ultra-high resolution are simply necessary. Such satellites, for example, include the Landsat and Sentinel models, which are responsible for the global study of the state of environment and security with a spatial resolution accuracy of up to 10 meters.

The era of satellite imagery brought the accuracy of maps to a resolution of 10 meters

Satellites regularly transmit terabytes of data in several spectra: visible, infrared, and some others. Information from the spectrum invisible to the human eye makes it possible to track changes in the relief, the state of the atmosphere, the ocean, the appearance of fires and even the growth of crops.

Satellite data is received and processed directly by their owners or official distributors, such as DigitalGlobe, Airbus Defense and Space and others. Based on the Global Land Survey (GLS) data, obtained mainly from the Landsat project, many different services have been created. Landsat satellites take pictures of everything the globe in real time since 1972. It is this project that remains the main source of information for all cartographic services when designing small-scale maps.

Satellite imagery offers a wide range of data on the entire earth's surface, but usually companies buy photos and data as an option and for certain areas. For densely populated areas, the images are detailed, while for less populated areas, images are taken in low resolution and in general terms. In cloudy areas, satellites take pictures several times until they achieve the desired result.

On the basis of satellite images and measurements of the area, vector maps are created, which are then sold to companies that print paper maps or create cartographic services (Google Maps, Yandex.Maps). It is very difficult and expensive to create maps based on satellite data on your own, so many corporations buy ready-made solutions based on the Google Maps API or Mapbox SDK and then finalize some details with their own staff of cartographers.

Satellite imagery and OpenStreetMap issues

In theory, in order to create a vector map, a satellite image and a graphic editor or service are enough to draw all objects from the image. But in reality, everything is not quite so: almost always, real objects on the surface of the earth do not correspond to digital data by several meters.

The distortion is due to the fact that all the satellites are photographing at an angle to the Earth at high speed. Therefore, recently, to clarify the location of objects, they began to use photo and video shooting, and even tracking cars. Also, to create accurate maps, orthocorrection is essential - the conversion of satellite images taken at an angle into strictly vertical images.

Map data received from satellites requires manual correction

And this is just the small tip of the iceberg. A new building was built, a ford appeared on the river, and part of the forest was cut down - all this is almost impossible to quickly and accurately detect using satellite images. In such cases, the OpenStreetMap project and similar projects come to the rescue, working on a similar principle.

OSM is a non-commercial project created in 2004, which is an open platform for creating a global geographical map. Anyone can contribute to improving the accuracy of the maps, whether it be photos, GPS tracks, videos, or simple local knowledge. By combining this information and satellite imagery, maps are created that are as close to reality as possible. To some extent, the OSM project is similar to Wikipedia, where people from all over the world work to create a free knowledge base.

Any user can independently edit the maps, and after checking and approving these changes by the project staff, the updated map becomes available to everyone. As a basis for creating maps, GPS tracks and satellite images from Bing, Mapbox, DigitalGlobe are used. Due to commercial restrictions, Google and Yandex maps cannot be used.

Open mapping projects allow anyone to join in creating accurate maps

To bind or move objects from a satellite image, geodata are used. Using a GPS receiver, you need to record as many track points as possible along linear features (road, coastline, railroad tracks, etc.), and then plot them on satellite images. The names of various objects with reference to geolocation are updated by Yelp, TripAdvisor, Foursquare, and others, who independently enter them on OpenStreetMap and Google Maps.

Outcome

Progress does not stand still, and cartography is no exception. Already, services are being created based on machine learning and neural networks that are able to independently add objects, determine densely populated areas and analyze maps. So far, this trend is not yet very visible, but in the near future, people may not have to edit maps in OSM at all. Cartographers believe that the future lies in the automatic creation of maps, where machine vision will be used to model objects with centimeter accuracy.