Grids file

This page is the generated field list for Grids.xml — named grid geometries for anything gridded: radar rainfall, NWP output, model grids. A grid is defined once here and referenced by id from imports, transformations, and displays.

At a glance

Purpose : Defines the geometry (rows/columns, cell size or corners, projection) of a named grid, as a regular grid, an irregular grid (shapefile/CSV/NetCDF cell centers), or a set of NetCDF files whose geometry is read directly from the file (UGRID mesh).

Folder : Config/RegionConfigFiles/

Root element : <grids> (no version attribute)

Used by : Grid imports/exports and grid-based transformations, by the grid’s locationId.

Minimal example

Config/RegionConfigFiles/Grids.xml

<?xml version="1.0" encoding="UTF-8"?>
<grids xmlns="http://www.wldelft.nl/fews">
  <regular locationId="RadarGrid">
    <rows>100</rows>
    <columns>120</columns>
    <firstCellCenter>
      <x>-125.0</x>
      <y>49.0</y>
    </firstCellCenter>
    <xCellSize>0.01</xCellSize>
    <yCellSize>0.01</yCellSize>
    <geoDatum>WGS 1984</geoDatum>
  </regular>
</grids>

Field reference

Note

RegularGridComplexType carries a full catalogue of projection types (polar stereographic, rotated pole, Lambert conformal conic, transverse Mercator, geostationary satellite view, and more) as alternatives to a plain geoDatum string — pick the one that matches your data source’s native projection. Most Pacific Northwest / CONUS radar and NWP grids just need geoDatum set to a standard datum like WGS 1984.

Auto-generated from grids.xsd. Descriptions are the schema's own annotations.

Element <grids>

Element	Type	Cardinality	Description
regular	RegularGridComplexType	required
irregular	IrregularGridComplexType	required
netcdfFiles	GridNetcdfFilesComplexType	required

RegularGridComplexType

Attributes

Attribute	Use	Notes
locationId	required	The grid location id. The grid for a time series is resolved by it's locationId or parent location id. The id is required by FEWS and since 2017.01 this is also required by the schema

Elements

Element	Type	Cardinality	Description
description	string	optional
rows	int	required	Number of rows in grid
columns	int	required	Number of columns in grid
gridCorners	GridCornersComplexType	required	Specify two grid corners instead of cell center and cell size(s). The corners can be specified in a different geo datum as the grid projection
firstCellCenter	GeoPointComplexType	required	Center of the upper left cell according to geo datum
xCellSize	double	required	Width of the grid cells
columnWidth	double	required · repeats	Column width. Repeat this element for every column
yCellSize	double	required	Height of the grid cells
rowHeight	double	required · repeats	Row height. Repeat this element for every row
z	double	optional · repeats	elevation of each cell, starting from upper left to bottom right row by row.
zBottom	double	optional · repeats	elevation of bottom for each cell, starting from upper left to bottom right row by row.
zTop	double	optional · repeats	elevation of top for each cell, starting from upper left to bottom right row by row.
zMapLayerName	nameStringType	optional	map layer with elevations for each cell, *.asc and *.bil files are supported.
zBottomMapLayerName	nameStringType	optional	map layer with elevations of bottom for each cell, *.asc and *.bil files are supported.
zTopMapLayerName	nameStringType	optional	map layer with elevations of top for each cell, *.asc and *.bil files are supported.
geoDatum	geoDatumStringType	required	Type of coordinate system.
projectionFile	fileStringType	required	PRJ file from the MapLayerFiles
polarStereographic	PolarStereographicGeoDatumComplexType	required	Define a custom stereoGraphic geo datum.
rotatedNorthPole	LatLongComplexType	required	Define a custom rotated pole geo datum based on WGS 1984. The rotation of the latitude/longitude grid is such that the intersection of the "prime meridian" and the "equator" has been located at the central latitude and longitude of the area represented.
rotatedSouthPole	LatLongComplexType	required	Define a custom rotated pole geo datum based on WGS 1984. The rotation of the latitude/longitude grid is such that the intersection of the "prime meridian" and the "equator" has been located at the central latitude and longitude of the area represented.
rotatedCartesian	RotatedCartesianComplexType	required	Rotates an existing geo datum with a cartesian coordinate system counter clock wise around a specified point.
lambertConformalConic	LambertConformalConicGeoDatumComplexType	required	Define a custom lambert conformal conic geo datum.
lambertAzimuthalEqualArea	LambertAzimuthalEqualAreaGeoDatumComplexType	required	Lambert AzimuthalEqualArea Projection spherical earth.
azimuthalEquidistant	AzimuthalEquidistantGeoDatumComplexType	required	Azimuthal equidistant projection
albersEqualArea	AlbersEqualAreaGeoDatumComplexType	required	AlbersEqualArea Projection spherical earth.
mercator	MercatorGeoDatumComplexType	required	does not support a latitude of natural origin other than the equator for now.
transverseMercator	TransverseMercatorGeoDatumComplexType	required	Transverse Mercator
geostationarySatelliteView	GeostationarySatelliteViewGeoDatumComplexType	required	Alias GEOS, Alias Normalized Geostationary Projection. Viewed from above the equator (latitude = zero, height = 35768 km). Only the central meridian parameter is required.

IrregularGridComplexType

Attributes

Attribute	Use	Notes
locationId	required

Elements

Element	Type	Cardinality	Description
description	string	optional	Optional description of the grid. This is never used in the code.
rows	positiveInteger	required	Number of rows in grid, at least two rows, don't configure for scattered points
columns	positiveInteger	required	Number of columns in grid, at least two columns, don't configure for scattered points
esriShapeFile	GridShapeFileComplexType	required	Shape file with cell polygons, lines and/or cell centers.
csvFile	GridCsvFileComplexType	required	Since 2013.01. Csv file with cell centers.
netcdfFile	GridNetcdfFileComplexType	required	Since 2015.02. Reference to a UGRID NetCDF file that contains only grid geometry meta data. This only supports mesh topologies (unstructured grids) with 2D coordinates. This can be 1D network, 2D triangular, 2D flexible or 3D layered mesh topologies. This currently only works for files that are compliant to the UGRID 1.0 conventions. For more information see https://github.com/ugrid-conventions/ugrid-conventions
geoDatum	geoDatumStringType	required	Coordinate system the grid is defined in. This may be a different coordinate system to that used in the main map display. The coordinate system may also differ per grid. A grid may be regular in one coordinate system, but may be irregular in another. Defining the grid in the regular coordinate system is generally easier.
cellCentre	GeoPointComplexType	required · repeats	Definition of the cell centre points of all cells in the irregular grid. The number of cellCentre points defined must be the same as the number of cells in the grid (rows x columns).

GridNetcdfFilesComplexType

Element	Type	Cardinality	Description
fileNameLocationIdPattern	nonEmptyStringType	optional	Iterate over files in the mapLayerFiles and read all netcdf that are matching with pattern. eg (.*)_flowgeom\.nc will match all files that ends with _flowgeom.nc and start with the location id. More complicated expressions can be found at http://en.wikipedia.org/wiki/Regular_expression
geoDatum	geoDatumStringType	optional	Optional. If the geoDatum of the coordinates cannot be determined from the infromation in the NetCDF file, then this geoDatum will be used. If this geoDatum is also not specified, then WGS 1984 will be used by default.
zVariableName	nonEmptyStringType	optional	Since 2017.01. Optional. Name of a data variable in the netcdf file that contains z coordinates. If this is specified, then the z coordinates in this variable will be used for the grid cells in this grid definition. This can be used e.g. to use bottom levels as z coordinates instead of using the z coordinates of the (3D) cell centers from the mesh itself.
locationIndexSetVariableName	nonEmptyStringType	required	Name of a location index set variable in the UGRID NetCDF file that contains the indices of the locations at which the data is defined. The location index set variable in the NetCDF file should point to a mesh topology variable and a (stagger) location within the mesh. This is only supported if the location index set variable in the NetCDF file contains coordinates (i.e. a coordinates attribute that points to coordinate variables that contain only coordinates for the index set, not for the entire mesh).
meshTopologyVariableName	nonEmptyStringType	required	Name of a mesh topology variable in the UGRID NetCDF file that contains the meta-data attributes of the mesh on which the data is defined.
staggerLocation	ugridMeshTopologyStaggerLocationEnumStringType	required	The (stagger) location within the mesh at which the data is defined. Only node, edge and face are supported. Data defined at nodes or edges will be handled as points in FEWS. Data defined at faces will be handled as polygons in FEWS. If the mesh in the netcdf file does not contain valid face bound coordinate variables, then data defined at faces will be handled as points in FEWS. One of: node, edge, face
spatialSubdomainNumberVariable	nonEmptyStringType	required	Since 2017.01.01. Variable that contains the domain numbers for each cell
visibleSpatialSubdomainNumber	int	required	Since 2017.01.01. Only the cells for this domain are visible.
visibleSpatialSubdomainNumberFileNamePattern	nonEmptyStringType	optional	Since 2023.02. Only the cells for this domain are visible. Parses the number form the filename. Eg for L12_99_flowgeom.nc use .*_(.*)_.* to get the 99 from the file name. More complicated expressions can be found at http://en.wikipedia.org/wiki/Regular_expression

GridCornersComplexType

Element	Type	Cardinality	Description
geoDatum	geoDatumStringType	optional	Coordinate system in which the grid corners are specified. If this is not configured, then the grid corners are specified in the coordinate system of the grid.
upperLeft	GeoPointComplexType	required	Upper left corner of the upper left cell.
lowerRight	GeoPointComplexType	required	Lower right corner of the lower right cell.
lowerLeft	GeoPointComplexType	required	Lower left corner of the lower left cell.
upperRight	GeoPointComplexType	required	Upper right corner of the upper right cell.

GeoPointComplexType

Element	Type	Cardinality	Description
x	double	required	X coordinate of the point (Easting)
y	double	required	Y coordinate of the point (Northing)
z	double	optional	Z coordinate of the point (altitude)

PolarStereographicGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required
originLongitude	double	required
equatorRadius	double	optional	Radius of equator in meters (approximate 6400000 meters)
poleRadius	double	optional	Radius at pole in meters (approximate 6400000 meters)
trueScalingLatitude	double	required
scaleAtOrigin	double	required

LatLongComplexType

Element	Type	Cardinality	Description
latitude	double	required
longitude	double	required

RotatedCartesianComplexType

Element	Type	Cardinality	Description
geoDatum	geoDatumStringType	required	Unrotated cartesian coordinate system.
x	double	required	Rotation point x coordinate
y	double	required	Rotation point y coordinate
counterClockwiseAngle	double	required	Counter clockwise rotation in degrees

LambertConformalConicGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required
originLongitude	double	required
firstStandardParallelLatitude	double	required
secondStandardParallelLatitude	double	required

LambertAzimuthalEqualAreaGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required
originLongitude	double	required
earthRadius	double	optional	Radius of earth in meters (approximate 6400000 meters)

AzimuthalEquidistantGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required
originLongitude	double	required
earthRadius	double	required	Radius of earth in meters (approximate 6400000 meters)
equatorRadius	double	required	Radius of earth at equator in meters (approximate 6400000 meters)
poleRadius	double	required	Radius of earth through poles in meters (approximate 6400000 meters)

AlbersEqualAreaGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required
originLongitude	double	required
standardParallel1	double	required	First standard parallel
standardParallel2	double	required	Second standard parallel
earthRadius	double	required	Radius of earth in meters (approximate 6400000 meters)
equatorRadius	double	required	Radius of earth at equator in meters (approximate 6400000 meters)
poleRadius	double	required	Radius of earth through poles in meters (approximate 6400000 meters)

MercatorGeoDatumComplexType

Element	Type	Cardinality	Description
originLongitude	double	required
standardParallelLatitude	double	required

TransverseMercatorGeoDatumComplexType

Element	Type	Cardinality	Description
originLatitude	double	required	Latitude of natural origin,
originLongitude	double	required	Longitude of natural origin, longitude of central meridian, longitude that the cylinder is tangent at central meridian
scaleFactorAtOrigin	double	required	Scale factor at natural origin, scale factor along the central meridian

GeostationarySatelliteViewGeoDatumComplexType

Element	Type	Cardinality	Description
centralMeridian	double	required	Position (longitude) of the satellite at the equator

GridShapeFileComplexType

Element	Type	Cardinality	Description
file	string	required	name of layer in the map layer files or a full absolute path to the shape file (*.shp). Can be a polygon shape file or point shape file.
geoDatum	geoDatumStringType	required	Geo datum of the coordinates, default is lat long, WGS 1984
projectionFileAvailable	boolean	required	A projection file has the same name as the shp file, only the with extension .prj instead of .shp. A prj file can be used instead of specifying the geo datum in the layer or map. When false the geo datum of the map will be used.
x	string	required	center X coordinate of the grid cell (Easting). e.g. %X%, put the actual column name between %%. When specified the shape file is optional only and only the dbf is required. When x and y are specified the coordinates are read from the shape file. When the coordinates in dbf file are different from the coordinates in the shape file a new shape file is automatically generated. This makes is possible to view and edit the dbf file with a gis. When the shape file contains polygons the x and y are required.
y	string	required	center Y coordinate of the grid cell (Northing) e.g. %Y%, put the actual column name between %%. When x and y are specified the shape file is optional and only the dbf is required. When x and y are not specified the coordinates are read from the shape file. This makes is possible to view and edit the dbf file with a gis. When the shape file contains polygons the x and y are required.
z	string	optional	center Z coordinate of the grid cel (altitude). e.g. %Z%, put the actual column name between %%.
area	string	optional	The area of the grid cell. e.g. %AREA%, put the actual column name between %%.
label	string	optional	Obsolete, no longer used. This is very memory hungry for large grids.

GridCsvFileComplexType

Element	Type	Cardinality	Description
file	string	required	name of layer in the map layer files or a full absolute path to the csv file.
geoDatum	geoDatumStringType	required	Geo datum of the coordinates, default is lat long, WGS 1984
projectionFileAvailable	boolean	required	A projection file has the same name as the shp file, only the with extension .prj instead of .csv. A prj file can be used instead of specifying the geo datum in the layer or map. When false the geo datum of the map will be used.
x	string	required	center X coordinate of the grid cell (Easting). e.g. %X%, put the actual column name between %%. When specified the shape file is optional only and only the dbf is required. When x and y are specified the coordinates are read from the shape file. When the coordinates in dbf file are different from the coordinates in the shape file a new shape file is automatically generated. This makes is possible to view and edit the dbf file with a gis. When the shape file contains polygons the x and y are required.
y	string	required	center Y coordinate of the grid cell (Northing) e.g. %Y%, put the actual column name between %%. When x and y are specified the shape file is optional and only the dbf is required. When x and y are not specified the coordinates are read from the shape file. This makes is possible to view and edit the dbf file with a gis. When the shape file contains polygons the x and y are required.
z	string	optional	center Z coordinate of the grid cel (altitude). e.g. %Z%, put the actual column name between %%.
area	string	optional	The area of the grid cell. e.g. %AREA%, put the actual column name between %%.
label	string	optional	Obsolete, no longer used. This is very memory hungry for large grids.

GridNetcdfFileComplexType

Element	Type	Cardinality	Description
file	fileStringType	required	Name of a UGRID NetCDF file in the map layer files folder or a full absolute path to a UGRID NetCDF file. The file must have extension ".nc".
geoDatum	geoDatumStringType	optional	Optional. If the geoDatum of the coordinates cannot be determined from the infromation in the NetCDF file, then this geoDatum will be used. If this geoDatum is also not specified, then WGS 1984 will be used by default.
zVariableName	nonEmptyStringType	optional	Since 2017.01. Optional. Name of a data variable in the netcdf file that contains z coordinates. If this is specified, then the z coordinates in this variable will be used for the grid cells in this grid definition. This can be used e.g. to use bottom levels as z coordinates instead of using the z coordinates of the (3D) cell centers from the mesh itself.
locationIndexSetVariableName	nonEmptyStringType	required	Name of a location index set variable in the UGRID NetCDF file that contains the indices of the locations at which the data is defined. The location index set variable in the NetCDF file should point to a mesh topology variable and a (stagger) location within the mesh. This is only supported if the location index set variable in the NetCDF file contains coordinates (i.e. a coordinates attribute that points to coordinate variables that contain only coordinates for the index set, not for the entire mesh).
meshTopologyVariableName	nonEmptyStringType	required	Name of a mesh topology variable in the UGRID NetCDF file that contains the meta-data attributes of the mesh on which the data is defined.
staggerLocation	ugridMeshTopologyStaggerLocationEnumStringType	required	The (stagger) location within the mesh at which the data is defined. Only node, edge and face are supported. Data defined at nodes or edges will be handled as points in FEWS. Data defined at faces will be handled as polygons in FEWS. If the mesh in the netcdf file does not contain valid face bound coordinate variables, then data defined at faces will be handled as points in FEWS. One of: node, edge, face
spatialSubdomainNumberVariable	nonEmptyStringType	required	Since 2017.01.01. Variable that contains the domain numbers for each cell
visibleSpatialSubdomainNumber	int	required	Since 2017.01.01. Only the cells for this domain are visible.
visibleSpatialSubdomainNumberFileNamePattern	nonEmptyStringType	optional	Since 2023.02. Only the cells for this domain are visible. Parses the number form the filename. Eg for L12_99_flowgeom.nc use .*_(.*)_.* to get the 99 from the file name. More complicated expressions can be found at http://en.wikipedia.org/wiki/Regular_expression

Gotchas

• A regular grid’s origin is firstCellCenter + xCellSize/yCellSize or gridCorners — pick one; don’t try to combine both ways of anchoring the grid.
• rows/columns order and the z/zBottom/zTop elevation arrays (when used) are read row by row, upper-left to lower-right — a transposed grid is a common source of silently-flipped data rather than an import error.
• The root <grids> element is a repeated choice of regular/irregular/ netcdfFiles entries — list as many named grids as you need in one file.

See also

• Schema: grids.xsd