Topographic mapping
A topographic survey is a geometrically accurate representation of the area of interest in the form of topographic maps. Topographic maps are scaled, georeferenced models which show theoretically all natural and man-made objects along with Earth’s surface relief (counter lines).
The scale of topographic survey defines the amount and type of objects to be depicted on the topographic maps. They are also dependent on the purpose of topographic surveys, accepted standards and the landscape, whether it is a city downtown, rural district, or remote forest area.
Zesmill specializes in the large topographical survey projects:
- topographic mapping of counties/administrative districts, mineral deposit areas, national parks etc. including Asian, African, Latin American countries, at a scale of 1:10,000-1:100,000
- topographic survey of urban areas, resorts, riparian areas at a scale of 1:2,000-1:10,000, e.g. for urban planning and infrastructural projects
- topographic survey of large industrial sites, ports, oil and gas fields, airports, railway station and yards etc.
- open pit mine surveys, 3D modeling and volumetric calculations
- RTK GNSS measurements for aerial imaging, land seismic profiling, environmental management projects etc.
- ground surface (DTM, DEM) and airspace obstruction mapping for aviation and mobile telecommunication industries
- aerial imaging, topographic and landscape mapping for the forest and wetland inventories
Zesmill provides highly informative topographic maps with a heavy emphasis on details. Our topographic maps and geodatabases contain 1.5-2 times more information than maps provided by many of government survey agencies.
Topographic survey usually includes:
- establishing the control geodetic network
- aerial imaging, if it is included in the project plan
- photogrammetric operations, including DEM and contour lines generation
- interpretation of aerial or very-high-resolution satellite images
- field surveys
- detailed survey of densely built areas (if any)
- collecting of additional information depending on project purpose (hydrological, floristic, demographic, soils, utilities etc.).
Map actualization (map revision) is the process of changing or adding information on a map. The aim of map actualization, or revision, is to keep topographic maps up to dated with changes taking place on the landscape.
Outdated topographic maps (many of which are downloadable or even for sale via the internet), like Soviet topographic maps, are almost useless. They can be of interest only to the scholars and geography lovers. While topographic map must be a terrain model which is maximally similar to the real landscape.
Actualization (revision) of topographic maps may include:
- transforming and re-projecting data with high accuracy GPS/GNSS measurements, if necessary
- implementing the new digital elevation model (DEM), redrawing of contour lines and spot elevation marks
- modeling the hydrographic network matching the new DEM
- identification followed by adding, removing, and changing signs depicting natural and man-made objects and phenomena
- adding thematic information from schemes and layouts, thematic maps, field observation and statistical data (depending on the project purpose)
- specification and checking state borders, provincial borders, city limits etc. depicted on a map.
Revision of topographic maps is a major task for the national (government) mapping agencies. While Zesmill, working with corporations directly, supplies an increasing demand for actualized topographic maps of particular areas of interest including new development areas, mineral deposits areas, irrigated lands, corridors for new railways, pipelines etc. as well as natural disaster areas. We also collaborate with municipal authorities and planning institution providing detailed topographic survey services for urban and rural planning.
Since 2009, Zesmill has delivered:
- 150,000 sq.km of digital orthophotography
- 35,000 sq.km of actualized topographic maps
- survey projects in usual and unusual (The Limestone Alps, The Karakum desert, Chernobyl Nuclear Plant exclusion zone) locations.