Orthophoto maps are a geometrically correct photographic image of the Earth's surface that eliminates all distortions caused by the slope of the scene and the effects of the terrain at the time the picture is taken, meaning that the photo can be considered equivalent to a map where different measurements can be made.
Orthophoto maps are made from aero photographs by processing them into specialized computer programs using photogrammetry techniques.
The LGIA orthophoto maps are prepared by the Latvian LKS-92 TM coordinate system for the whole territory of Latvia according to the specified resolution:
- 1994-1999 (1st cycle) - black and white orthophoto map with 1 m / pix resolution;
- 2003-2005 (2nd cycle) - color orthophoto map with 1 m / pix resolution;
- 2007-2008 (3rd cycle) - color orthophoto map with a resolution of 0.5 m / pix;
- 2010-2011 (cycle 4) - colored orthophoto map with a resolution of 0.5 m / pix meter;
- 2013-2015 (cycle 5) - colored orthophoto map with resolution of 0.4 m / pix, but for Riga and its surroundings - with resolution of 0.25 m / pix;
- 2016-2018 (cycle 6) - Color and infrared orthophoto cards with 0.25 m / pix resolution.
Orthophoto maps for the whole territory of Latvia are prepared in TIFF format according to the scale of map division of TKS-93: city orthophoto maps are divided according to topographic
- on a plan scale of 1: 2000 for the nomenclature of pages (1x1km2)
- orthophoto maps up to 2005 (cycles 1 and 2) divided according to topographic map scale 1: 10 000 nomenclature pages (5x5km2)
- orthophoto maps from 2007 on a scale of 1: 5 000 pages of nomenclature (2.5x2.5km2)
Digital height moodel
The digital terrain model (with a step between points of 20 meters) is a set of points on the Earth's surface, where each point has known plane coordinates (X, Y) and altitude (Z). The model is obtained by aerial laser scanning. Some of the data has been obtained with special stereo instruments using aerial photographs. The points cover the area in the form of a regular network
The basic data of the digital height model is a set of classified aerial laser scanning points, where each point has known plane coordinates (X, Y) and altitude (Z). The model data are linked to the coordinate system LKS-92 TM and the Latvian normal height system LAS-2000.5. Basic data were obtained by aerial laser scanning method. The total density of the obtained points is not less than 4 p / m², the average density of the points characterizing the ground surface is not less than 1.5 p / m².
Overview map of the Republic of Latvia in scale 1: 250 000, Topographic map in scale 1:50 000, 2nd edition, Map nomenclature, Satellite map.
On Martch 14th, 2007, after almost 3 years of reconciliation, Directive 2007/2 / EC of the European Parliament and of the Council establishing an Infrastructure for Spatial Information in Europe was adopted.
In the Community (INSPIRE). The requirements of the INSPIRE Directive had to be transposed by the Member States of the European Union by 14 May 2009.
The aim of the directive is to create more and better publicly available geospatial data, i.e. to create harmonized geospatial data sets to be delivered to users through Internet services. The main users of such services will be European Community institutions and bodies, Member States' public (public) authorities and the private sector.
Place names database
The database of place names contains information on place names (geographical names or toponyms) of the border area of Latvia and neighboring countries and the corresponding geographical objects - both natural objects and man-made objects. It is possible to see the searched objects on maps of different scales. For more on the place name database, see:
Data from the database of the national geodetic network
The National Geodetic Network Database (VGTDB) contains up-to-date information on the National Geodetic Network. Both textual and graphical information on the points of the State Geodetic Network is accumulated in the GSTDB. See more about VGTDB: