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geotiffinfo.m
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function info = geotiffinfo(fileOrURL)
%GEOTIFFINFO Information about GeoTIFF file
%
% INFO = GEOTIFFINFO(FILENAME) returns a structure whose fields contain
% image properties and cartographic information about a GeoTIFF file.
%
% FILENAME is a string scalar or character vector that specifies the name
% of the GeoTIFF file. Include the folder name in FILENAME or place the
% file in the current folder or in a folder on the MATLAB path. If the
% named file includes the extension '.TIF' or '.TIFF' (either upper or
% lower case), you can omit the extension from FILENAME.
%
% If the named file contains multiple GeoTIFF images, INFO is a structure
% array with one element for each image in the file. For example,
% INFO(3) would contain information about the third image in the file. If
% multiple images exist in the file, it is assumed that each image has
% the same cartographic information and the same image width and height.
%
% INFO = GEOTIFFINFO(URL) reads the GeoTIFF image from a URL. The URL
% must include the protocol type (e.g., "http://").
%
% The INFO structure contains these fields:
%
% Filename Character vector containing the name of the file or URL.
%
% FileModDate Character vector containing the modification date of the
% file.
%
% FileSize Integer indicating the size of the file in bytes.
%
% Format Character vector containing the file format, which
% should always be 'tiff'.
%
% FormatVersion Character vector or number specifying the file format
% version.
%
% Height Integer indicating the height of the image in pixels.
%
% Width Integer indicating the width of the image in pixels.
%
% BitDepth Integer indicating the number of bits per pixel.
%
% ColorType Character vector indicating the type of image:
% 'truecolor' for a truecolor (RGB) image,
% 'grayscale' for a grayscale image,
% 'indexed' for an indexed image.
%
% ModelType Character vector indicating the type of coordinate
% system used to georeference the image:
% 'ModelTypeProjected', 'ModelTypeGeographic',
% 'ModelTypeGeocentric' or ''.
%
% PCS Character vector indicating the projected coordinate
% system.
%
% Projection Character vector describing the EPSG identifier for the
% underlying projection method.
%
% MapSys Character vector indicating the map system, if
% applicable:
% 'STATE_PLANE_27', 'STATE_PLANE_83',
% 'UTM_NORTH', 'UTM_SOUTH', or ''.
%
% Zone Double indicating the UTM or State Plane Zone number,
% empty ([]) if not applicable or unknown.
%
% CTProjection Character vector containing the GeoTIFF identifier for
% the underlying projection method.
%
% ProjParm N-by-1 double containing projection parameter values.
% The identify of each element is specified by the
% corresponding element of ProjParmId. Lengths are in
% meters, angles in decimal degrees.
%
% ProjParmId N-by-1 cell array listing the projection parameter
% identifier for each corresponding numerical element
% ProjParm. The possible values are:
% 'ProjNatOriginLatGeoKey'
% 'ProjNatOriginLongGeoKey'
% 'ProjFalseEastingGeoKey'
% 'ProjFalseNorthingGeoKey'
% 'ProjFalseOriginLatGeoKey'
% 'ProjFalseOriginLongGeoKey'
% 'ProjCenterLatGeoKey'
% 'ProjCenterLongGeoKey'
% 'ProjAzimuthAngleGeoKey'
% 'ProjRectifiedGridAngleGeoKey'
% 'ProjScaleAtNatOriginGeoKey'
% 'ProjStdParallel1GeoKey'
% 'ProjStdParallel2GeoKey'
%
% GCS Character vector indicating the geographic coordinate
% system.
%
% Datum Character vector indicating the projection datum type,
% such as
% 'North American Datum 1927' or
% 'North American Datum 1983'.
%
% Ellipsoid Character vector indicating the ellipsoid name as
% defined by the ellipsoid.csv EPSG file.
%
% SemiMajor Double indicating the length of the semimajor axis
% of the ellipsoid, in meters.
%
% SemiMinor Double indicating the length of the semiminor axis
% of the ellipsoid, in meters.
%
% PM Character vector indicating the prime meridian location,
% for example, 'Greenwich' or 'Paris'.
%
% PmLongToGreenwich Double indicating the decimal degrees of longitude
% between this prime meridian and Greenwich. Prime
% meridians to the west of Greenwich are negative.
%
% UOMLength Character vector indicating the units of length used in
% the projected coordinate system.
%
% UOMLengthInMeters Double defining the UOMLength unit in meters.
%
% UOMAngle Character vector indicating the angular units used for
% geographic coordinates.
%
% UOMAngleInDegrees Double defining the UOMAngle unit in degrees.
%
% TiePoints Structure containing the image tiepoints.
% The structure contains these fields:
%
% ImagePoints Structure containing row and column
% coordinates of each image tiepoint.
% The structure contains these fields:
% Row Double array of size 1-by-N.
% Col Double array of size 1-by-N.
%
% WorldPoints Structure containing the x and y
% world coordinates of the tiepoints.
% The structure contains these fields:
% X Double array of size 1-by-N.
% Y Double array of size 1-by-N.
%
% PixelScale 3-by-1 array that specifies the X,Y,Z pixel scale
% values.
%
% SpatialRef Map raster reference object if ModelType is 'ModelTypeProjected',
% or a geographic raster reference object if ModelType is
% 'ModelTypeGeographic'. If ModelType is empty, a warning
% is issued and SpatialRef is a map raster reference object.
% SpatialRef is empty if ModelType is 'ModelTypeGeocentric',
% or if the spatial referencing is ambiguously defined by
% the GeoTIFF file, or if ModelType is 'ModelTypeGeographic'
% and the geometric transformation type is 'affine'.
%
% RefMatrix 3-by-2 double referencing matrix that must be
% unambiguously defined by the GeoTIFF file. Otherwise it
% is empty.
%
% BoundingBox 2-by-2 double array that specifies the minimum (row 1)
% and maximum (row 2) values for each dimension of the
% image data in the GeoTIFF file.
%
% CornerCoords Structure with six fields that contains coordinates of
% the outer corners of the GeoTIFF image. Each field is a
% 1-by-4 double array, or empty ([]) if unknown. The
% arrays contain the coordinates of the outer corners of
% the corner pixels, starting from the (1,1) corner and
% proceeding clockwise:
%
% X Easting coordinates in the projected coordinate
% system. X equals Lon (below) if the model type is
% 'ModelTypeGeographic'.
%
% Y Northing coordinates in the projected coordinate
% system. Y equals Lat if the model type is
% 'ModelTypeGeographic'.
%
% Row Row coordinates of the corner.
%
% Col Column coordinates of the corner.
%
% Lat Latitudes of the corner.
%
% Lon Longitudes of the corner.
%
% GeoTIFFCodes Structure containing raw numeric values for those
% GeoTIFF fields that are encoded numerically in the file.
% These raw values, converted to a character vector
% elsewhere in the INFO structure, are provided here for
% reference.
%
% The GeoTIFFCodes are:
% Model
% PCS
% GCS
% UOMLength
% UOMAngle
% Datum
% PM
% Ellipsoid
% ProjCode
% Projection
% CTProjection
% ProjParmId
% MapSys
%
% Each is scalar except for ProjParmId which is a column
% vector.
%
% GeoTIFFTags Structure containing field names that match the GeoTIFF
% tags found in the file. At least one GeoTIFF tag must be
% present in the file or an error is issued.
% The following fields may be included:
%
% ModelPixelScaleTag 1-by-3 double
% ModelTiepointTag 1-by-6 double
% ModelTransformationTag 1-by-16 double
% GeoKeyDirectoryTag scalar structure
% GeoAsciiParamsTag character vector
% GeoDoubleParamsTag 1-by-N double
% RPCCoefficientTag scalar map.geotiff.RPCCoefficientTag
%
% The GeoKeyDirectoryTag contains field names that match
% the names of the "GeoKeys". For more information about
% the "GeoKeys" refer to the GeoTIFF specification at
% http://geotiff.maptools.org/spec/geotiff6.html#6.2
%
% The RPCCoefficientTag contains properties with names
% corresponding to the tag elements listed in the
% "RPCs in GeoTIFF" technical note at:
% http://geotiff.maptools.org/rpc_prop.html
%
% ImageDescription Character vector describing the image. If no
% description is included in the file, the field is
% omitted.
%
% Example
% -------
% info = geotiffinfo('boston.tif')
%
% See also GEOTIFFREAD, GEOTIFFWRITE, map.geotiff.RPCCoefficientTag, PROJFWD, PROJINV
% Copyright 1996-2018 The MathWorks, Inc.
%
% Modified for reading Landsat COG data, which may have multiple tiff_infos(see L.279&280 in this code)
% This would require the function constructGeoKeyDirectoryMap at the end.
% by Shi May 8, 2020
% Validate the input. If it's a filename, return the full pathname. If it's
% a URL, download the URL to a temporary file and set isURL to true.
if nargin > 0
fileOrURL = convertStringsToChars(fileOrURL);
end
[filename, isURL] = internal.map.checkfilename( ...
fileOrURL, {'tif', 'tiff'}, mfilename, 1, true);
if (isURL)
% Delete temporary file from Internet download regardless if any
% errors are issued.
clean = onCleanup(@() deleteDownload(filename));
end
% Create the information structure from contents in the file.
info = readinfo(filename);
if (isURL)
% Replace the temporary file name with the URL.
info.Filename = fileOrURL;
end
%------------------------- info functions ---------------------------------
function info = readinfo(filename)
% Read the GeoTIFF info from the file and return the information structure.
% Obtain the TIFF information structure from the file.
tiff_info = tiffinfo(filename);
% modified for reading Landsat COG data, which may have multiple tiff_infos
tiff_info = tiff_info(1); % force to use the first layer
tiff_info(1).GeoTIFFTags = tiff_info(1).GeoTIFFTags(1); % force to use the first GeoTag
% Validate that at least one GeoTIFF tag exists in the file.
map.internal.assert(~isempty(fieldnames(tiff_info(1).GeoTIFFTags)), ...
'map:geotiff:expectedGeoTIFFTags', filename, 'IMFINFO')
% Ensure that all images have the same Height and Width values.
map.internal.assert(isconsistent(tiff_info.Height) && isconsistent(tiff_info.Width), ...
'map:geotiff:inconsistentImageSizes');
% Obtain the GeoTIFF tags from the TIFF info structure.
tags = tiff_info(1).GeoTIFFTags;
% Obtain height and width variables from the first element.
height = tiff_info(1).Height;
width = tiff_info(1).Width;
% Obtain the GeoTIFF information structure from the TIFF tags.
gtiff_info = gtiffinfo(tags, height, width);
% Construct a new information structure and copy the input data to it.
info = copyinfo(tiff_info, gtiff_info);
%--------------------------------------------------------------------------
function tiff_info = tiffinfo(filename)
% Obtain subset of TIFF information from filename.
% Turn off TIFF library warnings for this function.
w = warning('off', 'imageio:tiffmexutils:libtiffWarning');
wobj = onCleanup(@()warning(w));
% Open and validate the file.
% Close the TIFF file when the function terminates.
t = Tiff(filename);
tobj = onCleanup(@()close(t));
% Obtain the tag names to retrieve from the file.
[tiffTags, optionalTags, geoTiffTags] = getTagNames();
% Obtain the TIFF tag values from the Tiff object and return a structure
% with field names that match the names of the requested tags.
tags = getTiffTags(t, tiffTags);
% Create the TIFF information structure.
tiff_info = tiffstruct(filename, tags);
% Add the TIFF tags to the structure.
tiff_info = addTiffTags(tiff_info, tags, optionalTags);
% Add the GeoTIFF tags to the structure.
tiff_info = addGeoTiffTags(tiff_info, tags, geoTiffTags);
%--------------------------------------------------------------------------
function gtiff_info = gtiffinfo(tags, height, width)
% Obtain GeoTIFF information from TIFF GeoTIFF tags.
% Create the GeoTIFF information structure.
gtiff_info = gtiffstruct();
% Obtain the model type from the GeoKeyDirectoryTag, if defined.
gtiff_info = modelinfo(gtiff_info, tags);
% Set UserDefined value.
gtiff_info.UserDefined = 32767;
switch gtiff_info.ModelType
case 'ModelTypeProjected'
% Obtain the PCS information from the tags.
gtiff_info = pcsinfo(gtiff_info, tags);
case 'ModelTypeGeographic'
% Obtain the GCS information from the tags.
gtiff_info = gcsinfo(gtiff_info, tags);
case 'ModelTypeGeocentric'
% Obtain any GCS and PCS information from the tags.
gtiff_info = gcsinfo(gtiff_info, tags);
gtiff_info = pcsinfo(gtiff_info, tags);
otherwise
end
% Obtain the spatial referencing information.
gtiff_info = spatialinfo(gtiff_info, tags, height, width);
%--------------------------------------------------------------------------
function gtiff_info = modelinfo(gtiff_info, tags)
% Construct the ModelType string and Model code values from the values in
% the GeoKeyDirectoryTag. If the GTModelTypeTags is contained in the
% GeoTIFFTags structure use that value for the Model code; otherwise,
% set it to []. Use the Model code value to determine the ModelType string.
tagname = 'GeoKeyDirectoryTag';
keyname = 'GTModelTypeGeoKey';
if isfield(tags, tagname) && isfield(tags.(tagname), keyname)
modelTypeValue = tags.(tagname).(keyname);
gtiff_info.GeoTIFFCodes.Model = modelTypeValue;
else
modelTypeValue = '';
gtiff_info.GeoTIFFCodes.Model = [];
end
switch modelTypeValue
case 1
gtiff_info.ModelType = 'ModelTypeProjected';
case 2
gtiff_info.ModelType = 'ModelTypeGeographic';
case 3
gtiff_info.ModelType = 'ModelTypeGeocentric';
otherwise
gtiff_info.ModelType = '';
end
%--------------------------------------------------------------------------
function gtiff_info = pcsinfo(gtiff_info, tags)
% Get the PCS information from the values in the GeoKeyDirectoryTag,
% if it is contained in the TAGS structure. Otherwise, do not modify the
% GTIFF_INFO structure.
tagname = 'GeoKeyDirectoryTag';
keyname = 'ProjectedCSTypeGeoKey';
if isfield(tags, tagname) && isfield(tags.(tagname), keyname)
% Obtain the geokeys from the GeoKeyDirectoryTag.
geokeys = tags.(tagname);
% Obtain the code number.
pcscode = geokeys.(keyname);
if pcscode > 0
% Search the pcs.override and pcs tables for this code.
result = pcsread(pcscode, gtiff_info.UserDefined);
% Assign the PCS code.
gtiff_info.GeoTIFFCodes.PCS = pcscode;
% Assign the PCS string.
gtiff_info.PCS = getStringValue(result, 'COORD_REF_SYS_NAME');
% Assign the projcode.
epsgname = 'COORD_OP_CODE';
keyname = 'ProjectionGeoKey';
if isfield(geokeys, keyname) && ~isempty(geokeys.(keyname))
default = geokeys.(keyname);
else
default = gtiff_info.UserDefined;
end
projcode = getDoubleValue(result, epsgname, default);
gtiff_info.GeoTIFFCodes.ProjCode = projcode;
% Obtain GCS code.
header_name = 'SOURCE_GEOGCRS_CODE';
code = getDoubleValue(result, header_name, gtiff_info.UserDefined);
% Search the gcs.override and gcs tables for this code.
% If the code is found in the geokeys, then override the projection
% GCS code.
gtiff_info = gcsinfo(gtiff_info, tags, code);
% Assign the projection values.
gtiff_info = projinfo(gtiff_info, projcode, geokeys);
% Assign the length unit values.
keyname = 'ProjLinearUnitsGeoKey';
code = getTagDoubleValue(geokeys, keyname, result, 'UOM_CODE');
gtiff_info = uomlengthinfo(gtiff_info, code);
end
end
%--------------------------------------------------------------------------
function gtiff_info = projinfo(gtiff_info, code, geokeys)
% Convert the code to projection values.
% Assign Projection values.
epsgname = 'COORD_OP_METHOD_CODE';
result = tableread('projop_wparm', code, epsgname, gtiff_info.UserDefined);
projmethod = getDoubleValue(result, epsgname, gtiff_info.UserDefined);
projname = getStringValue(result, 'COORD_OP_NAME');
gtiff_info.Projection = projname;
gtiff_info.GeoTIFFCodes.Projection = projmethod;
% Assign CTProjection values.
keyname = 'ProjCoordTransGeoKey';
if isfield(geokeys, keyname)
% Code is found in the geokey. Convert the standard CT code number to a
% CTProjection name.
projcode = geokeys.(keyname);
gtiff_info.CTProjection = codeToCTProjection(projcode);
else
% Code is found in EPSG table. Convert the code value to a CTProjection
% name. Using the inverse map, lookup the CTProjection code from the
% CTProjection name.
if code ~= gtiff_info.UserDefined
projcode = projmethod;
[projname, inverseMap] = codeToCTProjection(projcode);
projcode = inverseMap(projname);
gtiff_info.CTProjection = projname;
else
% code is user-defined.
projcode = code;
gtiff_info.CTProjection = '';
end
end
gtiff_info.GeoTIFFCodes.CTProjection = projcode;
% Assign UTM, State Plane, and Zone EPSG values.
UTM_North = -9001;
UTM_South = -9002;
State_Plane_27 = -9003;
State_Plane_83 = -9004;
UTM_zone_1N = 16001;
UTM_zone_60N = 16060;
UTM_zone_1S = 16101;
UTM_zone_60S = 16160;
if code >= UTM_zone_1N && code <= UTM_zone_60N
mapSysCode = UTM_North;
mapSys = 'UTM_NORTH';
zone = code - UTM_zone_1N + 1;
elseif code >= UTM_zone_1S && code <= UTM_zone_60S
mapSysCode = UTM_South;
mapSys = 'UTM_SOUTH';
zone = code - UTM_zone_1S + 1;
elseif code >= 10101 && code <= 15299
if rem(code, 100) >= 30
mapSysCode = State_Plane_83;
mapSys = 'STATE_PLANE_83';
zone = code - 10000 - 30;
else
mapSysCode = State_Plane_27;
mapSys = 'STATE_PLANE_27';
zone = code - 10000;
end
else
mapSysCode = gtiff_info.UserDefined;
zone = gtiff_info.UserDefined;
mapSys = '';
end
% Assign the MapSys and Zone values.
gtiff_info.GeoTIFFCodes.MapSys = mapSysCode;
gtiff_info.MapSys = mapSys;
gtiff_info.Zone = zone;
% Assign ProjParm info values.
gtiff_info = projparamsinfo(gtiff_info, result, geokeys);
%--------------------------------------------------------------------------
function gtiff_info = projparamsinfo(gtiff_info, result, geokeys)
% Assign the ProjParm info parameters.
[idToNameMap, nameToIdMap] = constructGeoKeyDirectoryMap;
projcode = gtiff_info.GeoTIFFCodes.CTProjection;
[name, inverseMap] = codeToCTProjection(projcode);
id = @(x)(nameToIdMap(lower(x)));
% Construct projParmCodes and EPSG codes values.
[projParmCodes, epsgCodes, EPSG] = constructProjParmCodes(name, id);
% Construct ProjParm values.
projParm = constructProjParm(result, EPSG, epsgCodes);
% Update proj params if the ProjCoordTansGeoKey has been set.
if isfield(geokeys, 'ProjCoordTransGeoKey')
[projParm, projParmCodes] = updateProjParm( ...
projParm, projParmCodes, geokeys, name, id);
end
% Translate codes to names.
projParmId = cell(size(projParmCodes));
idToNameMap(0) = 'Unknown-0';
for k=1:numel(projParmCodes)
projParmId{k} = idToNameMap(projParmCodes(k));
end
% Assign values to gtiff_info.
gtiff_info.GeoTIFFCodes.ProjParmId = projParmCodes;
gtiff_info.ProjParmId = projParmId;
gtiff_info.ProjParm = projParm;
% Adjust projection parameters if using CT_PolarStereographic_B.
if strcmp(name, 'CT_PolarStereographic_B')
gtiff_info = adjustPolarStereographicBParams(gtiff_info, inverseMap);
end
%--------------------------------------------------------------------------
function gtiff_info = gcsinfo(gtiff_info, tags, code)
% Get the GCS string from the value in the GeoKeyDirectoryTag,
% if it is contained in the GeoTIFFTags structure, otherwise, return empty.
if ~exist('code', 'var')
code = 0;
end
if isfield(tags,'GeoKeyDirectoryTag')
% Obtain the geokeys from the GeoKeyDirectoryTag.
geokeys = tags.GeoKeyDirectoryTag;
if isfield(geokeys, 'GeographicTypeGeoKey')
% Obtain the code number for the key.
code = geokeys.GeographicTypeGeoKey;
end
else
geokeys =struct();
end
if code > 0
% Search the gcs.override and gcs tables for this code.
result = gcsread(code, gtiff_info.UserDefined);
% Assign the GCS code.
gtiff_info.GeoTIFFCodes.GCS = code;
% Assign the GCS string.
gtiff_info.GCS = getStringValue(result, 'COORD_REF_SYS_NAME');
% Assign the angle unit values.
% Note: The GeoTIFF library uses the angle code from the datum if
% defined rather than the code from the key, if given. For
% compatibility, use the code from the datum information if provided.
% In the future, this behavior should change. Remove the four lines
% below and replace them with this one.
% code = getTagDoubleValue(geokeys, keyname, result, 'UOM_CODE');
keyname = 'GeogAngularUnitsGeoKey';
code = getDoubleValue(result, 'UOM_CODE', gtiff_info.UserDefined);
if code == gtiff_info.UserDefined
code = getTagDoubleValue(geokeys, keyname, result, 'UOM_CODE');
end
gtiff_info = uomangleinfo(gtiff_info, code);
% Assign the Datum code.
keyname = 'GeogGeodeticDatumGeoKey';
code = getTagDoubleValue(geokeys, keyname, result, 'DATUM_CODE');
gtiff_info.GeoTIFFCodes.Datum = code;
% Search the datum.csv table for this code.
epsgname = 'datum_name';
result = tableread('datum', code, epsgname, gtiff_info.UserDefined);
% Assign the Datum string.
gtiff_info.Datum = getStringValue(result, epsgname);
% Assign the PM code.
keyname = 'GeogPrimeMeridianGeoKey';
code = getTagDoubleValue(geokeys, keyname, result, 'prime_meridian_code');
gtiff_info.GeoTIFFCodes.PM = code;
% Assign the PM values.
gtiff_info = pminfo(gtiff_info, code);
% Assign the Ellipsoid code.
keyname = 'GeogEllipsoidGeoKey';
code = getTagDoubleValue(geokeys, keyname, result, 'ellipsoid_code');
gtiff_info.GeoTIFFCodes.Ellipsoid = code;
% Assign the ellipsoid values.
gtiff_info = ellipsoidinfo(gtiff_info, geokeys, code);
end
%--------------------------------------------------------------------------
function gtiff_info = pminfo(gtiff_info, code)
% Search the prime_meridian table for the code.
% Check to see if the prime meridian code is for Greenwich since it is the
% most common code used.
PM_Greenwich = 8901;
if code == PM_Greenwich
gtiff_info.PM = 'Greenwich';
gtiff_info.PMLongToGreenwich = 0;
else
epsgname = 'PRIME_MERIDIAN_NAME';
result = tableread('prime_meridian', code, epsgname, gtiff_info.UserDefined);
gtiff_info.PM = getStringValue(result, epsgname);
epsgname = 'GREENWICH_LONGITUDE';
gtiff_info.PMLongToGreenwich = getDoubleValue(result, epsgname, 0);
end
gtiff_info.GeoTIFFCodes.PM = code;
%--------------------------------------------------------------------------
function gtiff_info = uomlengthinfo(gtiff_info, code)
% Search the unit_of_measure table for the code.
% Save time with common values.
switch code
case 9001
gtiff_info.UOMLength = 'metre';
gtiff_info.UOMLengthInMeters = 1.0;
case 9002
gtiff_info.UOMLength = 'foot';
gtiff_info.UOMLengthInMeters = .3048;
case 9003
gtiff_info.UOMLength = 'US survey foot';
gtiff_info.UOMLengthInMeters = 12.0/39.37;
otherwise
[name, factor_b, factor_c] = uomread(code, gtiff_info.UserDefined);
gtiff_info.UOMLength = name;
if isempty(factor_b) || isempty(factor_c)
dfInMeters = 0.0;
else
dfInMeters = factor_b / factor_c;
end
gtiff_info.UOMLengthInMeters = dfInMeters;
end
% Assign the UOMLength code.
gtiff_info.GeoTIFFCodes.UOMLength = code;
%--------------------------------------------------------------------------
function gtiff_info = uomangleinfo(gtiff_info, code)
% Search the unit_of_measure table for the code.
% Save time with common values.
switch code
case 9101
gtiff_info.UOMAngle = 'radian';
gtiff_info.UOMAngleInDegrees = 180.0 / pi;
case {9102 9107 9108 9110 9122}
gtiff_info.UOMAngle = 'degree';
gtiff_info.UOMAngleInDegrees = 1.0;
case 9103
gtiff_info.UOMAngle = 'arc-minute';
gtiff_info.UOMAngleInDegrees = 1.0 / 60.0;
case 9104
gtiff_info.UOMAngle = 'arc-second';
gtiff_info.UOMAngleInDegrees = 1.0 / 3600.0;
case 9105
gtiff_info.UOMAngle = 'grad';
gtiff_info.UOMAngleInDegrees = 180.0 / 200.0;
case 9106
gtiff_info.UOMAngle = 'gon';
gtiff_info.UOMAngleInDegrees = 180.0 / 200.0;
case 9109
gtiff_info.UOMAngle = 'microradian';
gtiff_info.UOMAngleInDegrees = 180.0 / (pi * 1000000.0);
otherwise
[name, factor_b, factor_c] = uomread(code, gtiff_info.UserDefined);
if factor_c ~= 0.0
angleInRadians = factor_b / factor_c;
angleInDegrees = angleInRadians * 180.0 / pi;
else
angleInDegrees = [];
end
gtiff_info.UOMAngle = name;
gtiff_info.UOMAngleInDegrees = angleInDegrees;
end
% Assign the UOMAngle code.
gtiff_info.GeoTIFFCodes.UOMAngle = code;
%--------------------------------------------------------------------------
function gtiff_info = ellipsoidinfo(gtiff_info, geokeys, code)
% Get the ellipsoid information using the code value. If the code equals
% UserDefined, then set the values to empty. Override SemiMajor and
% SemiMinor values if found in the geokeys.
if code == gtiff_info.UserDefined || isempty(code) || code <= 0
gtiff_info.Ellipsoid = ''; % 'UserDefined'
gtiff_info.SemiMajor = [];
gtiff_info.SemiMinor = [];
elseif code > 0
% Obtain the ellipsoid values from the table.
e = epsgread('ellipsoid', code);
% Assign the Ellipsoid name, SemiMajor, and SemiMinor values.
gtiff_info.Ellipsoid = e.Ellipsoid;
gtiff_info.SemiMajor = e.SemiMajor;
gtiff_info.SemiMinor = e.SemiMinor;
end
% Check for overridden SemiMajor and SemiMinor parameters.
keyname = 'GeogSemiMajorAxisGeoKey';
if isfield(geokeys, keyname)
gtiff_info.SemiMajor = geokeys.(keyname);
end
keyname = 'GeogSemiMinorAxisGeoKey';
if isfield(geokeys, keyname)
gtiff_info.SemiMinor = geokeys.(keyname);
end
%--------------------------------------------------------------------------
function gtiff_info = spatialinfo(gtiff_info, tags, height, width)
% Obtain the spatial referencing information.
% Assign the PixelScale value.
if isfield(tags, 'ModelPixelScaleTag')
gtiff_info.PixelScale = tags.ModelPixelScaleTag';
else
gtiff_info.PixelScale = [];
end
% Construct the spatial referencing object.
gtiff_info.SpatialRef = constructSpatialRef( ...
tags, height, width, gtiff_info.ModelType);
% Construct the referencing matrix.
gtiff_info.RefMatrix = constructRefMatrix(gtiff_info.SpatialRef);
% Construct the TiePoints structure.
gtiff_info.TiePoints = constructTiePoints(tags);
% Construct the BoundingBox array.
gtiff_info.BoundingBox = constructBoundingBox(gtiff_info.SpatialRef);
% Construct the CornerCoords structure.
gtiff_info = constructCornerCoords(gtiff_info, gtiff_info.SpatialRef);
%------------------------- struct functions -------------------------------
function tiff_info = tiffstruct(filename, tags)
% Create the TIFF information structure. tags is a structure array with one
% element per TIFF directory. optionalTags is a cell array of strings.
% Create the information structure.
requiredFields = { ...
'Filename', ...
'FileModDate', ...
'FileSize', ...
'Format', ...
'FormatVersion', ...
'Height', ...
'Width', ...
'BitDepth', ...
'ColorType'};
tiff_info = cell2struct(cell(size(requiredFields)), requiredFields, 2);
numdirs = numel(tags);
tiff_info(numdirs) = tiff_info;
% Obtain information about the file.
d = dir(filename);
fileModDate = d.date;
fileSize = d.bytes;
fileFormat = 'tif';
% Copy data to the tiff_info structure.
[tiff_info.Filename] = deal(filename);
[tiff_info.FileModDate] = deal(fileModDate);
[tiff_info.FileSize] = deal(fileSize);
[tiff_info.Format] = deal(fileFormat);
[tiff_info.FormatVersion] = deal([]);
[tiff_info.Height] = deal(tags.ImageLength);
[tiff_info.Width] = deal(tags.ImageWidth);
%--------------------------------------------------------------------------
function gtiff_info = gtiffstruct()
% Create the GeoTIFF information structure.
codes = struct( ...
'Model', [], ...
'PCS', [], ...
'GCS', [], ...
'UOMLength', [], ...
'UOMAngle', [], ...
'Datum', [], ...
'PM', [], ...
'Ellipsoid', [], ...
'ProjCode', [], ...
'Projection', [], ...
'CTProjection', [], ...
'MapSys', [], ...
'ProjParmId', []);
gtiff_info = struct( ...
'ModelType', '', ...
'PCS', '', ...
'GCS', '', ...
'UOMLength', '', ...
'UOMLengthInMeters', [], ...
'UOMAngle', '', ...
'UOMAngleInDegrees', [], ...
'Datum', '', ...
'PM', '', ...
'PMLongToGreenwich', [], ...
'Ellipsoid', '', ...
'SemiMajor', [], ...
'SemiMinor', [], ...
'Projection', '', ...
'CTProjection', '', ...
'ProjParm', [], ...
'ProjParmId', '', ...
'PixelScale', [], ...
'MapSys', '', ...
'Zone', [], ...
'CornerCoords', [], ...
'GeoTIFFCodes', codes);
%--------------------------------------------------------------------------
function info = infostruct(tiff_info)
% Initialize info structure and set it's size to the size of tiff_info.
info = struct( ...
'Filename', '', ...
'FileModDate', '', ...
'FileSize', [], ...
'Format', '', ...
'FormatVersion', [], ...
'Height', [], ...
'Width', [], ...
'BitDepth', [], ...
'ColorType', '', ...
'ModelType', '', ...
'PCS', '', ...
'Projection', '', ...
'MapSys', '', ...
'Zone', [], ...
'CTProjection', '', ...
'ProjParm', [], ...
'ProjParmId', [], ...
'GCS', '', ...
'Datum', '', ...
'Ellipsoid', '', ...
'SemiMajor', [], ...
'SemiMinor', [], ...
'PM', '', ...
'PMLongToGreenwich', [], ...
'UOMLength', '', ...
'UOMLengthInMeters', [], ...
'UOMAngle', '', ...
'UOMAngleInDegrees', [], ...
'TiePoints', [], ...
'PixelScale', [], ...
'SpatialRef', [], ...
'RefMatrix', [], ...
'BoundingBox', [], ...
'CornerCoords', [], ...
'GeoTIFFCodes', [], ...
'GeoTIFFTags', []);
if isfield(tiff_info,'ImageDescription')
info.ImageDescription = '';
end
info(numel(tiff_info)) = info;
%--------------------------------------------------------------------------
function EPSG = epsgstruct()
% Construct EPSG structure.
EPSG = struct( ...
'NatOriginLat' , 8801, ...
'NatOriginLong' , 8802, ...
'NatOriginScaleFactor' , 8805, ...
'FalseEasting' , 8806, ...
'FalseNorthing' , 8807, ...
'ProjCenterLat' , 8811, ...
'ProjCenterLong' , 8812, ...
'Azimuth' , 8813, ...
'AngleRectifiedToSkewedGrid' , 8814, ...
'InitialLineScaleFactor', 8815, ...
'ProjCenterEasting' , 8816, ...
'ProjCenterNorthing' , 8817, ...
'PseudoStdParallelScaleFactor' , 8819, ...
'FalseOriginLat' , 8821, ...
'FalseOriginLong' , 8822, ...
'StdParallel1Lat' , 8823, ...
'StdParallel2Lat' , 8824, ...
'FalseOriginEasting' , 8826, ...
'FalseOriginNorthing' , 8827, ...
'StdParallelLat' , 8832, ...
'OriginLong' , 8833);
%------------------------- read functions ---------------------------------
function result = epsgread(table, code)
% Search the EPSG table for the code value. If found, return a structure,
% otherwise return empty.
% For performance reasons, cache the found results into the persistent
% variable epsgtables. Only store the found results since the entire
% database is over 80 MB when converted to a structure.
persistent epsgtables
if isempty(epsgtables) || ~isstruct(epsgtables)
epsgtables = struct();
end
% Remove any '.' from table name.
tablename = strrep(table, '.', '_');
% Cache the override EPSG tables since so few requests will actually find
% data from these tables and they are small.
override_names = {'pcs_override', 'gcs_override'};
% Assign a logical if reading the ellipsoid table.
readingEllipsoid = strcmp('ellipsoid', tablename);