GDAL Geospatial Data Abstraction Library http:www'gdal'org

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GDALGeospatial Data Abstraction
Libraryhttp//www.gdal.org

• Translator library for raster geospatial data
  formats
• OpenSourceX/MIT style license
• Recently supported by ER Mapper
• Commandline like old Arc/Info

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OGR Simple Features Library

• Comes with GDAL and is the GDAL analog for vector
  data.
• Provides conversion capabilities between a number
  of different formats

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Supported Platforms

• Available as binaries or source
• Linux
• Windows
• Mac

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FWToolsOpen Source GIS Binary Kit for Windows
and Linuxhttp//fwtools.maptools.org/

• OpenEV A high performance raster/vector desktop
  data viewer and analysis tool.
• MapServer A web mapping package.
• GDAL/OGR A library and set of commandline
  utility applications for reading and writing a
  variety of geospatial raster (GDAL) and vector
  (OGR) formats.
• PROJ.4 A cartographic projections library with
  commandline utilities.
• OGDI a multi-format raster and vector reading
  techology noteworthy for inclusion of support for
  various military formats including VPF (ie. VMAP,
  VITD), RPF (ie. CADRG, CIB), and ADRG.
• Python a scripting language

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GDAL Included Utility Programs

• GDALinfo - report information about a file.
• GDAL_translate - Copy a raster file, with control
  of output format.
• GDALaddo - Add overviews to a file.
• GDALwarp - Warp an image into a new coordinate
  system.
• GDALtindex - Build a MapServer raster tileindex.
• GDAL_contour - Contours from DEM.
• Rgb2pct.py - Convert a 24bit RGB image to 8bit
  paletted.
• Pct2rgb.py - Convert an 8bit palatted image to
  24bit RGB.
• GDAL_merge.py - Build a quick mosaic from a set
  of images.
• GDAL_config - Get options required to build
  software using GDAL.

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GDALinfo

• Usage
• gdalinfo -mm -nogcp -nomd datasetname
• The gdalinfo program lists various information
  about a GDAL supported raster dataset.
• The gdalinfo will report all of the following (if
  known)
• The format driver used to access the file.
• Raster size (in pixels and lines).
• The coordinate system for the file (in OGC WKT).
• The geotransform associated with the file
  (rotational coefficients are currently not
  reported).
• Corner coordinates in georeferenced, and if
  possible lat/long based on the full geotransform
  (but not GCPs).
• Ground control points.
• File wide (including subdatasets) metadata.
• Band data types.
• Band color interpretations.
• Band block size.
• Band descriptions.
• Band min/max values (internally known and
  possibly computed).
• Band NODATA value.
• Band overview resolutions available.

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GDALinfo

• Driver GTiff/GeoTIFF
• Size is 6973, 8099
• Coordinate System is
• PROJCS"NAD83 / UTM zone 13N",
• GEOGCS"NAD83",
• DATUM"North_American_Datum_1983",
• SPHEROID"GRS 1980",6378137,298.257222
  1010042,
• AUTHORITY"EPSG","7019",
• AUTHORITY"EPSG","6269",
• PRIMEM"Greenwich",0,
• UNIT"degree",0.0174532925199433,
• AUTHORITY"EPSG","4269",
• PROJECTION"Transverse_Mercator",
• PARAMETER"latitude_of_origin",0,
• PARAMETER"central_meridian",-105,
• PARAMETER"scale_factor",0.9996,
• PARAMETER"false_easting",500000,
• PARAMETER"false_northing",0,
• UNIT"metre",1,

• Origin (153069.286401,3928716.424654)
• Pixel Size (1.000000,-1.000000)
• Corner Coordinates
• Upper Left ( 153069.286, 3928716.425)
  (108d49'17.83"W, 35d26'29.27"N)
• Lower Left ( 153069.286, 3920617.425)
  (108d49'5.44"W, 35d22'6.95"N)
• Upper Right ( 160042.286, 3928716.425)
  (108d44'41.84"W, 35d26'37.93"N)
• Lower Right ( 160042.286, 3920617.425)
  (108d44'29.70"W, 35d22'15.59"N)
• Center ( 156555.786, 3924666.925)
  (108d46'53.70"W, 35d24'22.46"N)
• Band 1 Block6973x1 TypeByte, ColorInterpGray
• Overviews 3487x4050, 1744x2025, 872x1013,
  436x507

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GDALtranslate

• The gdal_translate utility can be used to convert
  raster data between different formats,
  potentially performing some operations like
  subsettings, resampling, and rescaling pixels in
  the process.
• Includes formats that have a YES under the
  creation column

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GDALaddo

• Used to build or rebuild overview images (pyramid
  files) for most supported file formats with one
  over several downsampling algorithms.

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GDALwarp

• A simple image reprojection and warping utility.
  The program can reproject to any supported
  projection, and can also apply GCPs stored with
  the image if the image is "raw" with control
  information.
• Mosaicing into an existing output file is
  supported if the output file already exist

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GDALtindex

• This program builds a shapefile with a record for
  each input raster file, an attribute containing
  the filename, and a polygon geometry outlining
  the raster. This output is suitable for use with
  UMN MapServer as a raster tileindex.
• This provides a very easy way to provide a
  virtual mosaic of a large amount of raster
  imagery via a MapServer site.

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GDAL_contour

• Build contour lines from a DEM
• Input raster can be any of the supported formats
• Vector output format can be any of the OGR
  supported formats

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GDAL_contour

• Build contour lines from a DEM
• Input raster can be any of the supported formats
• Vector output format can be any of the OGR
  supported formats

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rgb2pct.py

• Python utility that will compute an optimal
  pseudo-color table for a given RGB image using a
  median cut algorithm on a downsampled RGB
  histogram.
• It then converts the image into a pseudo-colored
  image using the color table. This conversion
  utilizes Floyd-Steinberg dithering (error
  diffusion) to maximize output image visual
  quality.

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pct2rgb.py

• Python utility that will convert a pseudocolor
  band on the input file into an output RGB file of
  the desired format. .

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GDAL_merge.py

• Python utility that will automatically mosaic a
  set of images.
• All the images must be in the same coordinate
  system and have a matching number of bands, but
  they may be overlapping, and at different
  resolutions.

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OGR Simple Features Library

• OGR Vector Formats
• Format Name Creation Georeferencing
• Arc/Info Binary Coverage No Yes
• Comma Separated Value (.csv) Yes No
• DODS/OPeNDAP No Yes
• ESRI Shapefile Yes Yes
• FMEObjects Gateway No Yes
• GML Yes No
• IHO S-57 (ENC) No Yes
• Mapinfo File Yes Yes
• Microstation DGN No No
• MySQL No No
• OGDI Vectors No Yes
• ODBC No Yes
• Oracle Spatial Yes Yes
• PostgreSQL Yes Yes
• SDTS No Yes
• SQLite Yes No
• UK .NTF No Yes

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OGRinfo

• The OGRinfo program lists information about an
  OGR supported data source
• Geometry type, spatial reference, attribute info
• Includes arguments for
• getting information for all files in a directory
• info only on a particular spatial extent
• Info for a set of records that match a SQL query

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OGR2OGR

• This program can be used to convert simple
  features data between file formats and
• Performing various operations during the process
  such as
• Spatial or attribute selections
• Reducing the set of attributes
• Setting the output coordinate system or even
  reprojecting the features during translation
• Appending to an existing layer

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OGRtindex

• The OGRtindex program can be used to create a
  tileindex file containing a list of the
  identities of a bunch of other files along with
  there spatial extents.
• This is primarily intended to be used with the
  UMN MapServer for tiled access to layers using
  the OGR connection type.