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--- technologies:geodata_concepts:crs:crs_orbit [2014/02/06 13:17]
jeroen.vermeulen@orbitgis.com [Custom CRS Definition]
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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, read [[crs_theory|]].
-  * **[[#Supported CRS]]**
-    * [[#EPSG Library]]
-    * [[#Local CRS Definitions]]
-    * [[#Custom CRS Definition]]
-    * [[#Vertical CRS Definitions / Geoid model]]
-  * **[[#Dataset CRS]]**
-  * **[[#MapCanvas CRS]]**
-===== 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:geodata_concepts:crs:crs_theory|]].
-{{  :technologies:geodata_concepts:crs:crs_select_window.png?nolink&900  |}}
-====== Supported CRS ======
-===== EPSG Library =====
-Orbit has the objective to support all coordinate system as they are described in the [[http://www.epsg-registry.org|EPSG database]] by the [[http://www.ogp.org.uk|OGP]] \\ (International Association of Oil and Gas Producers).
-\\ \\
-Up to now Orbit supports Geographic, Geocentric and Metric projected coordinate systems. \\
-If you desire the support of Feet projected coordinate system, please let us know. It is on our shortlist for a feature update.
-===== 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://www.ngi.be/|NGI]] | [[technologies:geodata_concepts:crs:epsg31370|]] |
-| Great Britain and \\ Republic of Ireland | [[http://www.ordnancesurvey.co.uk/oswebsite/index.html|Ordnance Survey]] | [[technologies:geodata_concepts:crs:epsg27700|]] |
-| ::: | ::: | [[technologies:geodata_concepts:crs:epsg29901|]] |
-| ::: | ::: | [[technologies:geodata_concepts:crs:epsg29903|]] |
-| Israel |  | GCS Israel / Israel TM Grid |
-| The Netherlands |  | [[technologies:geodata_concepts:crs:epsg28992|]] |
-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://www.opengeospatial.org/docs/01-009.pdf |Well-known-text (WKT)]].
-  * Practical documentation for use in Orbit : [[technologies:geodata_concepts:crs:prj|]]
-==== 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  should be placed in the "<installdir>\program\system\crs" directory
-  - The name of the file should be a numeric code, like "1031370.prj" for example. \\ The numeric code should be larger than 1000000 (one million) to avoid overlap with existing EPSG codes. An optional description can be added to the filename if an underscore character follows the numeric code, like "1031370_Belge 1972 - Belgian Lambert 72.prj" for example.
-  - After starting Orbit the newly added CRS systems can be found by selecting "Undefined Area" from the CRS area (By Country) list.
-===== Vertical CRS Definitions / Geoid model / DEM =====
-{{  :technologies:geodata_concepts:crs:vertical_crs.png?450&nolink|}}
-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 or dem via an Orbit raster file.
-\\ \\
-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:resources:supported_formats|supported raster resource]]. \\
-The Orbit team will prepare the required configuration files which can be added on the fly like a custom CRS definition.
-====== 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:datasets:general:index|]]
-  * [[orbitgis:datasetlist:dataset:context_menu|]]
-The dataset CRS is saved in the Orbit Resource Descriptor file :
-  * [[technologies:geodata_concepts:ord|]]
-====== 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:mapcanvas:statusbar|]]
-The MapCanvas CRS can be saved in the workspace file :
-  * [[orbitgis:workspace:file:ogw|]]

Last modified:: 2014/02/06 13:17