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technologies:geodata_concepts:crs:crs_orbit [2014/01/14 14:14] jeroen.vermeulen@orbitgis.com [Vertical CRS Definitions / Geoid model] |
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- | ===== Coordinate Reference Systems in Orbit ====== | ||
- | This page describes only the use and application of Coordinate Reference Systems in Orbit. \\ | ||
- | For clear and short overview of the concepts of coordinate systems, datum and projections, | ||
- | |||
- | * **[[# | ||
- | * [[#EPSG Library]] | ||
- | * [[#Local CRS Definitions]] | ||
- | * [[#Custom CRS Definition]] | ||
- | * [[#Vertical CRS Definitions / Geoid model]] | ||
- | * **[[# | ||
- | * **[[# | ||
- | ===== CRS / SRS ===== | ||
- | |||
- | A coordinate reference system (CRS) or spatial reference system (SRS) is a coordinate-based local, regional or global system used to locate geographical entities. A coordinate reference system defines a specific map projection, as well as transformations between different spatial reference systems. \\ | ||
- | Coordinate reference systems can be referred to using a SRID integer, including EPSG codes defined by the International Association of Oil and Gas Producers. | ||
- | \\ \\ | ||
- | Read more, [[technologies: | ||
- | |||
- | {{ : | ||
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- | ====== Supported CRS ====== | ||
- | |||
- | ===== EPSG Library ===== | ||
- | |||
- | Orbit has the objective to support all coordinate system as they are described in the [[http:// | ||
- | |||
- | ===== Local CRS Definitions ===== | ||
- | |||
- | The following local coordinate are supported as defined by their local entity, both for XY and Z. | ||
- | |||
- | ^ Country ^ Local service ^ Coordinate system ^ | ||
- | | Belgium | [[http:// | ||
- | | Great Britain and \\ Republic of Ireland | [[http:// | ||
- | | ::: | ::: | [[technologies: | ||
- | | ::: | ::: | [[technologies: | ||
- | | Israel | | GCS Israel / Israel TM Grid | | ||
- | | The Netherlands | | [[technologies: | ||
- | |||
- | |||
- | Contact the Orbit support to embed your local defined coordinate system. | ||
- | ===== Custom CRS Definition ===== | ||
- | |||
- | The EPSG dataset does not and cannot record all possible geodetic parameters in use around the world. Orbit supports custom created CRS definitions if they are structured as well-known text as described by the Open Geospatial Consortium : | ||
- | * International documentation : [[http:// | ||
- | * Practical documentation for use in Orbit : [[technologies: | ||
- | |||
- | ==== How to add custom CRS definition ==== | ||
- | |||
- | - Create a plain ASCII text file with the extension .prj and insert the projection parameters as a WKT (well known text) definition on a single line | ||
- | - The prj-file | ||
- | - The name of the file should be a numeric code, like " | ||
- | - After starting Orbit the newly added CRS systems can be found by selecting " | ||
- | |||
- | ===== Vertical CRS Definitions / Geoid model ===== | ||
- | |||
- | Since Oribt 10.3 vertical coordinate systems are supported via mathematical description. \\ | ||
- | Since Orbit 10.5 an intelligent engine can be used to add any geoid model via a grid correction. | ||
- | \\ \\ | ||
- | To support your local geoid model in Orbit you can provide your geoid (raster) definition and specifications to the Orbit support team (support at orbitgis dot com). This can be as text/csv file (containing X,Y,Z) or any [[technologies: | ||
- | The Orbit team will prepare the required configuration files which can be added like a custom CRS definition. | ||
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- | ====== Dataset CRS ====== | ||
- | |||
- | Every single resource has a CRS. \\ | ||
- | If no Orbit datsaet CRS is set, Orbit will read the resource assuming that dataset has the same coordinate system as the MapCanvas (see below). When combining resources with different coordinate system it is strongly recommended to define the coordinate system for every single resource. | ||
- | |||
- | There are two ways to set the CRS of a dataset in Orbit : | ||
- | * [[orbitgis: | ||
- | * [[orbitgis: | ||
- | The dataset CRS is saved in the Orbit Resource Descriptor file : | ||
- | * [[technologies: | ||
- | |||
- | ====== MapCanvas CRS ======= | ||
- | |||
- | The MapCanvas CRS is the coordinate system that will be used to display and re-project if required all datasets. \\ | ||
- | Set the MapCanavas CRS wise. If a vector dataset needs to be reprojected this can take some time for very large datasets. | ||
- | \\ \\ | ||
- | Set the CRS of the MapCanavs using statusbar : | ||
- | * [[orbitgis: | ||
- | The MapCanvas CRS can be saved in the workspace file : | ||
- | * [[orbitgis: |
Last modified:: 2014/01/14 14:14