Georeference, analyze and transform gridded data

Raster data, also known as data grids, stores map data as matrices. Regular data grids require a referencing object, vector, or matrix that describes the sampling and location of the data points. Geolocated data grids explicitly identify the latitude and longitude coordinates of all rows and columns.

`georefcells` | Reference raster cells to geographic coordinates |

`georefpostings` | Reference raster postings to geographic coordinates |

`refmatToGeoRasterReference` | Referencing matrix to geographic raster reference object |

`refvecToGeoRasterReference` | Referencing vector to geographic raster reference object |

`makerefmat` | Construct affine spatial-referencing matrix |

`georesize` | Resize geographic raster |

`geointerp` | Geographic raster interpolation |

`latlon2pix` | Convert latitude-longitude coordinates to pixel coordinates |

`pix2latlon` | Convert pixel coordinates to latitude-longitude coordinates |

`setpostn` | Convert latitude-longitude to data grid rows and columns |

`setltln` | Convert data grid rows and columns to latitude-longitude |

`limitm` | Determine latitude and longitude limits of regular data grid |

`filterm` | Filter latitudes and longitudes based on underlying data grid |

`findm` | Latitudes and longitudes of nonzero data grid elements |

`geocontourxy` | Contour grid in local system with latitude-longitude results |

`geoloc2grid` | Convert geolocated data array to regular data grid |

`ltln2val` | Extract data grid values for specified locations |

`changem` | Substitute values in data array |

`imbedm` | Encode data points into regular data grid |

`encodem` | Fill in regular data grid from seed values and locations |

`meshgrat` | Construct map graticule for surface object display |

`geopeaks` | Generate synthetic data set on sphere |

`maprefcells` | Reference raster cells to map coordinates |

`maprefpostings` | Reference raster postings to map coordinates |

`refmatToMapRasterReference` | Referencing matrix to map raster reference object |

`mapresize` | Resize projected raster |

`mapinterp` | Map raster interpolation |

`map2pix` | Convert map coordinates to pixel coordinates |

`pix2map` | Convert pixel coordinates to map coordinates |

`pixcenters` | Compute pixel centers for georeferenced image or data grid |

`mapoutline` | Compute outline of georeferenced image or data grid |

`mapbbox` | Compute bounding box of georeferenced image or data grid |

`georasterref` | Construct geographic raster reference object |

`maprasterref` | Construct map raster reference object |

`refmatToWorldFileMatrix` | Convert referencing matrix to world file matrix |

`worldFileMatrixToRefmat` | Convert world file matrix to referencing matrix |

`GeographicCellsReference` | Reference raster cells to geographic coordinates |

`GeographicPostingsReference` | Reference raster postings to geographic coordinates |

`MapCellsReference` | Reference raster cells to map coordinates |

`MapPostingsReference` | Reference raster postings to map coordinates |

Raster geodata represents map data in matrix format.

Each element of georeferenced raster data corresponds to a defined quadrangle of territory on a planet.

**Types of Data Grids and Raster Display Functions**

You can display regular and geolocated data grids in many ways, such as a 2-D indexed image where color represents the data value, or as a 3-D surface with light shading.

This example shows how to store a matrix in a geographic referencing object. Display the matrix on a map, and specify display properties such as the projection, axes labels, and color map.

**Compute Map Limits for Regular Data Grids**

This example shows how to find the maximum and minimum latitude and longitude of a regular data grid that has a referencing vector.

**Convert Between Geographic and Intrinsic Coordinates**

You can work with gridded geodata using either geographic coordinates, which specify latitude and longitude, or intrinsic raster coordinates, which specify matrix indices.

**Precompute the Size of a Data Grid**

This example shows how to compute the expected size of a large data grid, before creating the grid, to confirm that the grid will be manageable and will fit in memory.

**Compute Gradient, Slope, and Aspect from Regular Data Grid**

This example shows how to compute relationships between neighboring cells in a regular data grid.

A geolocated data grid is defined by three matrices giving latitude and longitude coordinates and indices associated with the mapped region.

**Geographic Interpretations of Geolocated Grids**

The dimensions of a map matrix and associated latitude and longitude matrices determines the interpretation of the geographic map data.

**Creating a Half-Resolution Georeferenced Image**

This example shows how to create a half-resolution version of a georeferenced TIFF image, using spatial referencing objects (requires Image Processing Toolbox™).

**Compute Elevation Profile Along Straight Line**

This example shows how to compute an elevation profile along a straight line by defining waypoints.

**Generate Shaded Relief Map using Raster Data**

This example shows how to generate a shaded relief map using geographic data in an array. You can change the displayed projection of the map without modifying the raster data.

**Data Grids as Logical Variables**

You can perform logic tests on data grid variables to create a binary logical grid.

**Determine Area Occupied by Logical Grid Variable**

This example shows how to use a logical grid to analyze regions with certain constraints. For example, find the area of a region that belongs both to a specified country and to a specified state.