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|
## Copyright (C) 2014-2022 Philip Nienhuis
##
## This program is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program. If not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} [@var{outstruct} ] = shaperead (@var{shp_filename})
## @deftypefnx {Function File} [@var{outstruct} ] = shaperead (@var{shp_filename}, @var{outstyle})
## @deftypefnx {Function File} [@var{outstruct} ] = shaperead (@var{shp_filename}, @var{outstyle}, @var{opts})
## @deftypefnx {Function File} [@var{outstruct}, @var{atts} ] = shaperead (@var{shp_filename}, ...)
## Read an ArcGis shapefile set (shp, shx and dbf).
##
## Depending on the value of @var{outstyle} some different output formats
## will be returned:
##
## @table @code
## @item 0 (numeric)
## @itemx ml (case-insensitive)
## @itemx m
## Return a Matlab-compatible M X 1 struct with a separate entry for each shape
## feature in the shape file. Each struct element contains fields "Geometry"
## (shape type), "BoundingBox" ([minX minY ; maxX maxY]), X, Y (coordinates of
## points in the shape item as row vectors). For multi-part items, the
## coordinates of each part are separated by NaNs. This output format supports
## neither M and Z type nor MultiPatch shape features. For M and Z type shape
## features the M and Z values will simply be ignored.
## The struct is augmented with attributes found in the accompanying .dbf file,
## if found.
##
## For ML-style output, if only one output argument is requested the attributes
## in the .dbf file will be augmented to that struct. If two output arguments
## are requested, the attributes will be returned separately in output struct
## @var{atts}.
##
## @item 1 (numeric)
## @itemx ext (case-insensitive)
## @itemx e
## Same as 1 but M and Z type and MultiPatch shape features are accepted. The
## resulting output struct is no more ML-compatible. If the shapefile contains
## M and/or Z type shape features the mapstruct or geostruct has extra fields M
## and -optionally- Z. Note that MultiPatch shape features may not have
## M-values even if Z-values are present. For MultiPatch shapes another field
## Parts is added, a Px2 array with zero-based indices to the first vertex of
## each subfeature in the XYZ fields in column 1 and the type of each
## subfeature in column 2; P is the number of shape feature parts.
##
## @item 2 (numeric)
## @itemx oct (case-insensitive)
## @itemx o
## Return a struct containing a N X 6 double array "vals" containing the X, Y,
## and Z coordinates, M-values, record nr. and type of each point in the shape
## file. If no M or Z values were present the relevant columns contain
## NaNs. Individual shape features and shape parts are separated by a row of
## NaN values. The field "idx" contains 1-based pointers into field vals to
## the first vertex of each shape feature.
## Field "bbox" contains an 8 X M double array of XYZ coordinates of the
## bounding boxes and min/max M-values corresponding to the M items found in
## the .shp file; for point shapes these contain NaNs.
## Field "npt" contains a 1 X M array of the number of points for each item.
## Field "npr" contains a 1 X M cell array containing a row of P part indices
## (zero-based) for each Polyline, Polygon or MultiPatch part in the shape
## file; for multipatch each cell contains another row with the part types;
## for other item types (point etc.) the cell array contains empty rows.
## A separate field "shpbox" contains the overall bounding box X, Y and Z
## coordinates and min/max M-values in a 4 X 2 double array. If the shape file
## contains no Z or M values the corresponding columns are filled with NaNs.
##
## The struct field "fields" contains a cellstr array with names of the columns.
## If a corresponding .dbf file was read, the struct array also contains
## a field for each attribute found in the .dbf file with the corresponding
## field name, each containing a 1 X M array of attribute values matching the
## M items in the .shp file. These arrays can be double, char or logical,
## depending on the type found in the .dbf file.
##
## @item 3 (numeric)
## @itemx dat (case-insensitive)
## @itemx d
## Same as OCT or 0 but without a row of NaN values between each shape
## file item in the VALS array.
## @end table
##
## If a character option is given, just one character will suffice. The default
## for @var{outstyle} is "ml".
##
## The output of 'shaperead' can be influenced by property-value pairs. The
## following properties are recognized (of which only the first three
## characters are significant, case doesn't matter):
##
## @table @code
## @item Attributes
## Normally all attributes associated with the shape features will be read
## and returned in the output struct(s). To limit this to just some
## attributes, enter a value consisting of a cell array of attribute names to
## be read. To have no attributes read at all, specify @{@}, an empty cell
## array. @*
## Attributes "Geometry", "BoundingBox", "X", "Y", "Lat", and "Lon" are
## contained within the .shp file and will be returned in any case. If
## specified these values will be ignored. In the unlikely case that the
## associated .dbf file also contains these attributes (truncated to 10
## characters) they will be prepended with an underscore (@code {_}).
##
## @item BoundingBox
## Select only those shape items (features) whose bounding box lies within, or
## intersects in at least one point with the limits of the BoundingBox value (a
## 2 X 2 double array [Minx, MinY; MaxX, MaxY]).
## No intersection or clipping with the BoundingBox value will be done by
## default!
##
## @item Clip
## (only useful in conjuction with the BoundingBox property) If a value of 1
## or true is supplied, clip all shapes to the bounding box limits. This
## option may take quite a bit of processing time. If a value of "0" or false
## is given, do not perform clipping. The default value is 0.
## Clipping is merely meant to be performed in the XY plane. Clipping 3D
## shapes is supported but may lead to unexpected results.
## For Z and M type polylines and polygons including MultiPatch and
## Longitude/Latitude/Height types, Z (Height) and M values for each vertex in
## the clipped shape feature are simply copied over from the nearest vertex in
## the original shape feature. This implies that Z and M values of new
## vertices created on the bounding box edges may be less optimal.
##
## For clipping polylines and polygons the Octave-Forge geometry package needs
## to be installed and loaded.
##
## @item Debug
## If a value of 'true' or 1 is given, shaperead echoes the current record
## number while reading. Can be useful for very big shapefiles. The default
## value is 0 (no feedback). If a Matlab-compatible output structarray is
## requested and the Bounding Box property is specified, the extracted shape
## feature indices are added to the field "___Shape_feature_nr___".
##
## @item RecordNumbers
## Select only those records whose numbers are listed as integer values in
## an array following RecordNumbers property. Neither the size nor the class of
## the array matters as long as it is a numeric array.
##
## @item UseGeoCoords
## (Only applicable if a Matlab-style output struct is requested). If a value
## of 'true' (or 1) is supplied, return a geostruct rather than a mapstruct.
## If a value of 0 or false is given, return a mapstruct.
## The mere difference is that in a geostruct the fields 'X' and 'Y' (and
## optionally 'Z') are replaced by 'Long' and 'Lat' (and 'Hght'). The
## default value is 'false' (return a mapstruct').
## @end table
##
## Ref: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
##
## @seealso{geoshow, mapshow, shapedraw, shapeinfo}
## @end deftypefn
## Author: Philip Nienhuis <prnienhuis@users.sf.net>
## Created: 2014-11-07
function [ outs, oatt ] = shaperead (fname, varargin);
## FIXME Implementation needed of these ML input arguments:
## - Selector (supposedly difficult. I'd prefer myself to leave this
## outside of shaperead, it needlessly complicates and slows
## this function /PRN)
## Check input
if (nargin < 1)
print_usage ();
endif
## Check file name
[pth, fnm, ext] = fileparts (fname);
if (isempty (ext))
bname = fname;
fname = [fname ".shp"];
elseif (isempty (pth))
## Later on bname.shx and bname.dbf will be read
bname = fnm;
else
## Later on bname.shx and bname.dbf will be read
bname = [pth filesep fnm];
endif
## Find out what args have been supplied
if (nargin == 1)
## Only filename supplied. Set "ml" (Matlab) type as default
outopts = 0;
elseif (nargin == 2)
## Assume filename + outopts was supplied
if (isempty (varargin{1}))
## Assume ML-style output
outopts = 0;
else
outopts = varargin{1};
endif
varargin = {};
elseif (rem (nargin, 2) == 0)
## Even number of input args => Outopts & at least one pair of varargin
outopts = varargin{1};
varargin(1) = [];
else
## Odd nr; maybe only filename and prop/val(s) supplied, outstyle skipped
if (ischar (varargin{1}))
## Check arg#2, must be a property name then
if (! ismember (lower (varargin{1}(1:min(3, numel (varargin{1})))), ...
{"att", "bou", "cli", "deb", "rec", "sel", "use"}))
error ("shaperead: property name expected for arg. #2");
endif
else
## no outstyle or property => wrong input
print_usage ();
endif
outopts = 0;
endif
## Check output type arg
if (isnumeric (outopts))
if (outopts < 0 || outopts > 3)
error ("shaperead: arg. #2 integer value out of range 0-3\n");
endif
elseif (ischar (outopts))
outopts = lower (outopts);
if (! any (strncmp (outopts, {"ml", "ext", "oct", "dat"}, 1)))
error (["shaperead: arg. #2 char value should be one of 'ml', 'ext', ", ...
"'oct' or 'dat'\n"]);
endif
switch outopts
case {"ml", "m"}
outopts = 0;
case {"ext", "e"}
outopts = 1;
case {"oct", "o"}
outopts = 2;
case {"dat", "d"}
outopts = 3;
otherwise
error (["shaperead: illegal value for arg. #2: '%s' - expected ", ...
"'ml', 'ext', 'oct' of 'dat'"], outopts);
endswitch
else
error ("shaperead: numeric or character type expected for arg. #2\n");
endif
## Check .shp file existence
fidp = fopen (fname, "r");
## Postpone file opening error until after other provisional input validation
if (fidp > 0)
## Temporarily close to avoid file handle leaks during further input checks
fclose (fidp);
endif
## - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
## Open .shx file to help speed up seeks to next records. We need this info
## for s_recs check below
have_shx = 0;
fidx = fopen ([bname ".shx"], "r");
if (fidx < 0)
s_recs = [];
else
fseek (fidx, 24, "bof");
fxlng = fread (fidx, 1, "int32", 72, "ieee-be");
nrec = (fxlng - 50) / 4;
fseek (fidx, 100, "bof");
## Get record start positions & -lengths in 16-bit words
ridx = reshape (fread (fidx, nrec*2, "int32", 0, "ieee-be"), 2, [])';
fclose (fidx);
## Get indices & lengths in bytes
ridx *= 2;
have_shx = 1;
s_recs = [1 : size(ridx, 1)];
endif
## Parse options; first set defaults
clip = 0;
dbug = 0;
s_atts = [];
s_bbox = [];
s_geo = 0;
## Init collection of records that meet BB criteria
bb_union = [];
## Process input args
for ii = 1:2:length (varargin)
if (! ischar (varargin{ii}))
error ("shaperead: property %d: property name expected but got a %s value", ...
(ii+1)/2, class (varargin{ii}));
elseif (numel (varargin{ii}) < 3)
warning ("shaperead: unknown option '%s' - ignored\n", varargin{ii});
else
switch (lower (varargin{ii})(1:3))
case "att"
## Select records based on attribute values
s_atts = varargin{ii+1};
## Weed out .shp file attributes
s_atts = setdiff (s_atts, {"Geometry", "BoundingBox", ...
"X", "Y", "Lat", "Lon"});
case "bou"
## Select whether record/shape features partly lie inside or outside limits
try
s_bbox = double (varargin{ii+1});
if (numel (s_bbox) != 4)
error ("shaperead: 2 X 2 numeric array expected for BoundingBox\n");
endif
catch
error ("shaperead: numeric 2 X 2 array expected for BoundingBox\n");
end_try_catch
## Initialize supplementary polygon array here
sbox = [s_bbox(1) s_bbox(3); s_bbox(2) s_bbox(3); s_bbox(2) s_bbox(4); ...
s_bbox(1) s_bbox(4); s_bbox(1) s_bbox(3)];
case "cli"
## Clip polygons to requested BoundingBox
try
clip = logical (varargin{ii+1});
catch
error ("numeric or logical value expected for 'Clip'\n");
end_try_catch
case "deb"
## Set verbose output (count records)
try
dbug = logical (varargin{ii+1});
catch
error ("numeric or logical value expected for 'Debug'\n");
end_try_catch
case "rec"
## Select record nrs directly. Check for proper type & clean up
try
s_recs = sort (unique (double (varargin{ii+1}(:))));
if (have_shx && any (s_recs > nrec))
printf (["shaperead: requested record nos. > nr. of records ", ...
"(%d) ignored\n"], nrec);
s_recs (find (srecs > nrec)) = [];
endif
catch
error ("shaperead: numeric value or array expected for RecordNumbers\n");
end_try_catch
case "sel"
## A hard one, to be implemented later?
printf ("shaperead: 'Selector' option not implemented, option ignored\n");
case "use"
## Return a geostruct or a mapstruct (default). Only for ML-structs
if (outopts != 0)
error ("shaperead: UseGeoCoords only valid for Matlab-style output\n");
endif
try
s_geo = logical (varargin{ii+1});
catch
error ("shaperead: logical value type expected for 'UseGeoCoords'\n");
end_try_catch
otherwise
warning ("shaperead: unknown option '%s' - ignored\n", varargin{ii});
endswitch
endif
endfor
## Post-processing
if (clip)
if (isempty (s_bbox))
warning ("shaperead: no BoundingBox supplied => Clip option ignored.\n");
clip = 0;
endif
if (isempty (which ("clipPolygon_clipper")))
## No OF geometry package?
printf ("shaperead: function 'clipPolygon' not found. Clip option ignored\n");
warning (" (OF geometry package installed and loaded?)\n");
clip = 0;
endif
if (isempty (which ("distancePoints")))
## No OF geometry package?
printf ("shaperead: function 'distancePoints' not found. Clip option ignored\n");
warning (" (OF geometry package installed and loaded?)\n");
clip = 0;
endif
endif
if (fidp < 0)
## Only now convey file open error message
error ("shaperead: can't open file %s\n", fname);
else
## Open .shp file
fidp = fopen (fname, "r");
endif
if (fidx < 0)
warning ("shaperead: index file %s not found\n", [fnm ".shx"]);
endif
## ============= Preparations done, now we can start reading ============
## ---------------------- 2. Read .shp file proper ----------------------
## Start reading header
fseek (fidp, 0, "bof");
## Read & check file code
fcode = fread (fidp, 1, "int32", 20, "ieee-be");
if (fcode != 9994)
error ("%s is not a valid shapefile\n", fname);
endif
flngt = fread (fidp, 1, "int32", 0, "ieee-be") * 2;
fvsn = fread (fidp, 1, "int32", 0, "ieee-le");
shpt = fread (fidp, 1, "int32"); ## Shape file type
shpbox.X(1) = fread (fidp, 1, "double");
shpbox.Y(1) = fread (fidp, 1, "double");
shpbox.X(2) = fread (fidp, 1, "double");
shpbox.Y(2) = fread (fidp, 1, "double");
shpbox.Z(1) = fread (fidp, 1, "double");
shpbox.Z(2) = fread (fidp, 1, "double");
shpbox.M(1) = fread (fidp, 1, "double");
shpbox.M(2) = fread (fidp, 1, "double");
## FIXME: scan shp file in advance to assess nr of XY points, to be able to
## preallocate rec array. May be difficult, .shp is not favorable for
## it. Initial tries showed no significant speed advantage yet over
## the incremental allocation scheme implemented in Ls. 611+ & 631+
## for oct/plt style output. For ml-style it is much harder as
## we'd need to preallocate a potentially very heterogeneous struct
## array.
## Prepare for unsupported (in ML output) shape types
unsupp = 0;
## Echo warning if dbug was set
ign_mz = (outopts == 0) && dbug;
## Buffer for record data
BUFSIZE = 10000;
## Read records, 1 by 1. Initialize final array
vals = npt = npr = bbox = idx = nullsh = [];
## Init nr. of shapes read
nshp = 0;
## Temp pointer to keep track of array size and increase it w. BUFSIZE rows
ivals = 1;
## Provisionally assume file has M (measure) values
has_M = true;
## Record index number (equals struct element number)
ir = 1;
## Init output struct
outs = repmat (struct ("Geometry", ""), 0, 1);
do
## If the .shx file is there, skip directly to requested record
if (have_shx)
fseek (fidp, ridx(s_recs(ir), 1), "bof");
endif
if (dbug)
printf ("Reading record %d ...\r", ir);
endif
val = NaN(1, 6);
## Read record index number & record length
val(5) = fread (fidp, 1, "int32", 0, "ieee-be");
rlen = fread (fidp, 1, "int32", 0, "ieee-be");
## Here we decide if the record need be read at all, based on s_recs
if (isempty (s_recs) || ismember (double (val(5)), s_recs))
## => this record # has been desired; proceed. Read shape feature type
val(6) = fread (fidp, 1, "int32");
rincl = 1; ## see s_bbox, below
## Init values for this shape item
tbbox = NaN(1, 8);
switch val(6)
case 1 ## Point
val(1:2) = fread (fidp, 2, "double");
val(3:4) = NaN;
tnpt = 1;
tnpr = 0;
case 11 ## PointZ
val(1:4) = fread (fidp, 4, "double");
tnpt = 1;
tnpr = 0;
case 21 ## PointM
val(1:2) = fread (fidp, 2, "double");
## "Z"
val(3) = 0;
## M
val(4) = fread (fidp, 1, "double");
tnpt = 1;
tnpr = 0;
case 8 ## Multipoint
## Read bounding box
tbbox(1:4) = fread (fidp, 4, "double");
tnpt = fread (fidp, 1, "int32");
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
val(1:tnpt, 3:4) = NaN;
## Copy rec index & type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
tnpr = 0;
case 18 ## MultipointZ
tbbox(1:4) = fread (fidp, 4, "double");
tnpt = fread (fidp, 1, "int32");
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## Z min & max values
tbbox(5:6) = fread (fidp, 2, "double");
## Augment val array with Z values
val(1:tnpt, 3) = fread(fidp, tnpt, "double")';
## M min & max values
tbbox(7:8) = fread (fidp, 2, "double");
if (val(1, 5) == 1)
has_M = checkM (fidp, val(1, 6), shpbox);
endif
if (has_M)
## Augment val array with M values
val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
## Copy rec index & type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
tnpr = 0;
endif
case 28 ## MultipointM
tbbox(1:4) = fread (fidp, 4, "double");
tnpt = fread (fidp, 1, "int32");
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## Insert empty column for Z
val(1:tnpt, 3:4) = NaN;
if (val(1, 5) == 1)
has_M = checkM (fidp, val(1, 6), shpbox);
endif
if (has_M)
## M min & max values
tbbox(7:8) = fread (fidp, 2, "double");
## Augment val array with M values
val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
endif
## Copy rec index & type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
tnpr = 0;
case {3, 5} ## Polyline/-gon
tbbox(1:4) = fread (fidp, 4, "double");
## Read nparts, npoints, nparts pointers
nparts = fread (fidp, 1, "int32");
tnpt = fread (fidp, 1, "int32");
tnpr = fread (fidp, nparts, "int32")';
## Read XY point coordinates
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## No Z or M data
val(1:tnpt, 3:4) = NaN;
## Copy rec index and type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
case {13, 15} ## Polyline/-gonZ
tbbox(1:4) = fread (fidp, 4, "double");
## Read nparts, npoints, nparts pointers
nparts = fread (fidp, 1, "int32");
tnpt = fread (fidp, 1, "int32");
tnpr = fread (fidp, nparts, "int32")';
## Read XY point coordinates
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## Z min & max values + data
tbbox(5:6) = fread (fidp, 2, "double");
val(1:tnpt, 3) = fread(fidp, tnpt, "double")';
if (val(1, 5) == 1)
has_M = checkM (fidp, val(1, 6), shpbox);
endif
if (has_M)
## M min & max values + data
tbbox(7:8) = fread (fidp, 2, "double");
val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
## Copy rec index and type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
endif
case {23, 25} ## Polyline/-gonM
tbbox(1:4) = fread (fidp, 4, "double");
## Read nparts, npoints, nparts pointers
nparts = fread (fidp, 1, "int32");
tnpt = fread (fidp, 1, "int32");
tnpr = fread (fidp, nparts, "int32")';
## Read XY point coordinates
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## No Z data
val(1:tnpt, 3) = NaN;
if (val(1, 5) == 1)
has_M = checkM (fidp, val(1, 6), shpbox);
endif
if (has_M)
## M min & max values + data
tbbox(7:8) = fread (fidp, 2, "double");
val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
## Copy rec index and type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
endif
case 31 ## Multipatch
tbbox(1:4) = fread (fidp, 4, "double");
## Read nparts, npoints, nparts pointers, npart types
nparts = fread (fidp, 1, "int32");
tnpt = fread (fidp, 1, "int32");
## Npart types is just another row under npart pointers => read both.
## Provisionally transpose, this is later on reset after NaN insertion
tnpr = reshape (fread (fidp, nparts*2, "int32")', [], 2)';
## Read XY point coordinates
val(1:tnpt, 1:2) = reshape (fread (fidp, tnpt*2, "double"), 2, [])';
## Z min & max values + data. Watch out for incomplete .shp file
EOF = (ftell (fidp) > flngt-2);
if (! EOF)
tbbox(5:6) = fread (fidp, 2, "double");
val(1:tnpt, 3) = fread(fidp, tnpt, "double")';
endif
fptr = ftell (fidp);
EOF = (fptr > flngt-2);
if (! EOF && has_M)
has_M = checkM (fidp, val(1, 6), shpbox);
endif
## M min & max values + data. Watch out for incomplete .shp file
if (! EOF && has_M)
tbbox(7:8) = fread (fidp, 2, "double");
val(1:tnpt, 4) = fread(fidp, tnpt, "double")';
endif
## Copy rec index and type down
val(2:tnpt, 5:6) = repmat (val(1, 5:6), tnpt-1, 1);
otherwise ## E.g., null shape (0)
## Keep track of null shapes to avoid reading associated attributes
if (val(1, 6) == 0)
nullsh = [ nullsh ir ];
rincl = 0;
elseif (abs(val(1, 6)) > 31)
error (["shaperead: unexpected shapetype value %f for feature ", ...
"# %d\n Looks like a faulty shape file."], ...
val(1, 6), ir);
endif
endswitch
## Check if (X, Y) are valid coordinates
if (any (abs (val(:, 1:2)) > 1.797e308))
## Probably +/- Inf
rincl = 0;
if (dbug)
printf ("shape# %d has no finite XY coordinates, skipped\n", ir);
endif
## Detect if shape lies (partly) within or completely out of BoundingBox.
## Null shapes are automatically skipped
elseif (! isempty (s_bbox))
## Just check if any shape feature bounding box corner lies in s_bbox
tbox = [tbbox(1) tbbox(2); tbbox(1) tbbox(4); ...
tbbox(3) tbbox(4); tbbox(3) tbbox(2); tbbox(1) tbbox(2)];
rincl = 0;
## For polygons, polylines & multipatches:
if (ismember (val(1, 6), [3, 13, 23, 5, 15, 25, 31])) ## Polygon/line
## To avoid undue CPU time for large shapes we take a shortcut:
## Check if shape feature lies in BoundingBox...
[a, b] = inpolygon (tbox(:, 1), tbox(:, 2), sbox(:, 1), sbox(:, 2));
## ...or BoundingBox lies in polyline/gon. Faster than indiv. points
[c, d] = inpolygon (sbox(:, 1), sbox(:, 2), tbox(:, 1), tbox(:, 2));
if (any ([a; b; c; d]))
## At least one of the shape item bbox corners lies within s_bbox
rincl = 1;
bb_union = unique ([bb_union val(1, 5)]);
## FIXME still the case of polygon edges intersecting bounding box
## w/o vertices inside bounding box. Clipping required for that
endif
elseif (ismember (val(1, 6), [1, 11, 21])) ## (Multi-)Point
## Simply select all points within or on boundaries
[a, b] = inpolygon (val(:, 1), val(:, 2), sbox(:, 1), sbox(:, 2));
val = val(find(a), :);
tnpt = size (val, 1);
if (tnpt)
rincl = 1;
endif
endif
## If clipping has been selected, clip all parts of the shape feature
if (rincl && clip)
## What to do depends on shape type. Null and MultiPatch aren't clipped
switch val(1, 6)
case {3, 13, 23, 5, 15, 25, 31} ## Polyline/gon, Multipatch
## Temporarily silence Octave a bit, then call clippln
warning ("off", "Octave:broadcast", "local");
[val, tnpt, tnpr] = clippln (val, tnpt, tnpr, sbox, val(1, 6));
otherwise
warning ("shaperead: unknown shape type found (%d) - ignored\n", ...
val(1, 6));
rincl = 0;
val = [];
endswitch
if (isempty (val))
## Don't include it and remove last added bb_union entry
bb_union(end) = [];
rincl = 0;
else
## Update bounding box
tbbox(1) = min (val(:, 1));
tbbox(2) = min (val(:, 2));
tbbox(3) = max (val(:, 1));
tbbox(4) = max (val(:, 2));
endif
endif
endif
## What to do with the val data, if to be included
if (rincl)
## Keep track of nr of shape features read
++nshp;
## M-values < -1e39 really mean absent values
im = find (val(:, 4) < -1e39);
val(im, 4) = NaN;
if (outopts < 3)
## Prepare an Octave or Matlab style struct optimized for fast
## plotting by inserting a NaN row after each polyline/-gon part
nn = size (tnpr, 2);
valt = NaN(tnpt + nn - 1, 6);
ipt = 1;
ttnpr = [tnpr(1, :) tnpt];
dtnpr = diff (ttnpr);
for ii=2:numel (ttnpr)
valt(ipt:ipt+dtnpr(ii-1)-1, :) = val(ttnpr(ii-1)+1:ttnpr(ii), :);
ipt += dtnpr(ii-1) + 1;
endfor
val = valt;
tnpr(1, :) = (tnpr(1, :) + [0:numel(dtnpr)-1]);
endif
## Shape either included by default or it lies in requested BoundingBox
switch outopts
case {0, 1}
## Return a ML compatible mapstruct. Attributes will be added later
if (ign_mz && val(1, 6) >= 10)
printf ("shaperead: M and Z values ignored for ml-style output\n");
ign_mz = 0;
endif
switch val(1, 6)
case {1, 11, 21} ## Point
outs(end+1, 1).Geometry = "Point";
case {8, 18, 28} ## Multipoint
outs(end+1, 1).Geometry = "MultiPoint";
case {3, 13, 23} ## Polyline
outs(end+1, 1).Geometry = "Line";
case {5, 15, 25} ## Polygon
outs(end+1, 1).Geometry = "Polygon";
otherwise
if (outopts == 1)
## "Extended" ML-style output struct
if (val(1, 6) == 31) ## MultiPatch
outs(end+1, 1).Geometry = "MultiPatch";
outs(end, 1).Parts = tnpr;
endif
else
if (! unsupp)
warning (["shaperead: shapefile contains unsupported ", ...
"shape types\n"]);
outs = oatt = [];
return
endif
outs(end+1, 1).Geometry = val(1, 6);
endif
endswitch
## Omit BoundingBox for Point
if (all ([1, 11, 21] - val(1, 6)))
outs(end).BoundingBox = reshape (tbbox(1:4), 2, [])';
endif
if (s_geo)
outs(end, 1).Lon = val(:, 1)';
outs(end, 1).Lat = val(:, 2)';
else
outs(end, 1).X = val(:, 1)';
outs(end, 1).Y = val(:, 2)';
endif
## (ML-incompatible) add Z- and optional M-values, if any
if (outopts == 1 && any (isfinite (val(:, 4))))
outs(end, 1).M = val(:, 4)';
## FIXME Decision needed if field Geometry should reflect the type
## outs{end}.Geometry = [ outs{end}.Geometry "M"];
endif
if (outopts == 1 && any (isfinite (val(:, 3))))
outs(end, 1).Z = val(:, 3)';
## FIXME Decision needed if field Geometry should reflect the type
## outs{end}.Geometry = [ outs{end}.Geometry "Z"];
endif
## (ML-incompatible) add Z- and optional M-values, if any
if (dbug)
## Add a field with shape feature identifier for boundingbox
outs(end, 1).___Shape_feature_nr___ = val(1, 5);
endif
case {2}
## Return an Octave style struct.
## Append to vals array; keep track of appended nr. of rows
lvals = size (vals, 1);
lval = size (val, 1);
if ((size (vals, 1) - ivals) < lval)
## Increase size of vals
vals = [ vals; NaN(BUFSIZE, 6) ];
endif
vals(ivals:ivals+lval-1, :) = val;
idx = [idx ; ivals];
ivals += lval;
## Add a row of NaNs
vals(ivals, :) = NaN(1,6);
++ivals;
## Append the other arrays
npt = [npt; tnpt];
if (isempty (npr))
npr = {tnpr};
else
npr = [npr; {tnpr}];
endif
bbox = [bbox; tbbox];
case {3}
## Return a compressed Octave style struct.
## Simply append to vals array; keep track of appended nr. of rows
lvals = size (vals, 1);
lval = size (val, 1);
if ((size (vals, 1) - ivals) < lval)
## Increase size of vals
vals = [ vals; NaN(BUFSIZE, 6) ];
endif
vals(ivals:ivals+lval-1, :) = val;
idx = [idx ; ivals];
ivals += lval;
## Append the other arrays
npt = [npt; tnpt];
if (isempty (npr))
npr = {tnpr};
else
npr = [npr; {tnpr}];
endif
bbox = [bbox; tbbox];
otherwise
endswitch
endif
else
## Record not in s_recs list, skip rest of record
fread (fidp, (rlen*2), "char=>char");
endif
## Next .shp record
++ir;
until (ftell (fidp) > flngt - 3 ||
(have_shx && ir > numel (s_recs))); ## i.e., within last
## file bytes or all
## req. records read
fclose (fidp);
## If no shape was read, or none fitted within BoundingBox, return empty
if (nshp < 1)
outs = oatt = {};
return;
endif
## ------------------------ Post-processing ------------------------
if (outopts > 1)
## Octave-style outstruct. Truncate vals to proper length
vals = vals(1:ivals-1, :);
if (outopts == 2 && ! isempty (vals))
## Remove last NaN row
vals(end, :) = [];
endif
if (isempty (vals))
s_recs = 0;
endif
endif
if (dbug)
if (outopts <= 1)
ii = numel (outs);
else
ii = numel (npt);
endif
printf ("\n%d records read. \n", ii);
endif
## For Octave style output, add separate arrays to output struct
if (outopts >= 2)
outs.shpbox = shpbox;
outs.vals = vals;
outs.bbox = bbox;
outs.npt = npt;
outs.npr = npr;
outs.idx = idx;
## Clear memory (for very large shape files)
clear shpbox vals bbox npt npr idx val;
outs = setfield (outs, "fields", {"shpbox", "vals", "bbox", "npt", "npr"});
endif
## Clean up s_recs and bb_union
if (! isempty (s_bbox))
s_recs = sort (unique (bb_union));
else
s_recs = sort (unique (s_recs));
endif
## Weed out any null shape records to prevent reading their attributes
if (! isempty (nullsh))
if (outopts >= 2 && ! isempty (s_recs))
s_recs = [1:numel (npt)];
endif
s_recs (ismember (nullsh, s_recs)) = [];
endif
## ---------------------- 3. .dbf ----------------------
if (iscell (s_atts) && isempty (s_atts))
## {} indicates no attributes to be read. Morph into ""
return;
endif
## Check if dbfread is available
if (isempty (which ("dbfread")))
printf ("shaperead: dbfread function not found. No attributes will be added.\n");
printf (" (io package installed and loaded?)\n");
oatt = {};
else
## Try to read the .dbf file
try
atts = dbfread ([ bname ".dbf" ], s_recs, s_atts);
if (! isempty (atts))
if (outopts < 2)
## First check if any attributes match fieldnames; if so, pre-/append "_"
tags = {"Geometry", "BoundingBox", "X", "Y", "Lat", "Lon"};
for ii=1:numel (tags)
idx = find (strcmp (tags{ii}, atts(1, :)));
if (! isempty (idx))
atts(1, idx) = ["_" atts{1, idx} "_"];
endif
endfor
## Matlab style map-/geostruct. Divide attribute values over struct elems
if (nargout < 2)
## Attributes appended to outs struct
for ii=1:size (atts, 2)
[outs.(atts{1, ii})] = deal (atts(2:end, ii){:});
endfor
oatt = [];
else
## Attributes separately in oatt struct
oatt(size (atts, 1) - 1).(atts{1, 1}) = [];
for ii=1:size (atts, 2)
[oatt.(atts{1, ii})] = deal (atts(2:end, ii){:});
endfor
oatt = oatt';
endif
else
## Octave output struct. Add attributes columns as struct fields
## Check if any attributes match fieldnames; if so, pre-/append "_"
tags = {"shpbox", "vals", "bbox", "npt", "npr", "idx", "Geometry", ...
"BoundingBox", "X", "Y", "Lat", "Lon"};
for ii=1:numel (tags)
idx = find (strcmp (tags{ii}, atts(1, :)));
if (! isempty (idx))
atts(1, idx) = ["_" atts{1, idx} "_"];
endif
endfor
for ii=1:size (atts, 2)
outs.fields(end+1) = atts{1, ii};
if (islogical (atts{2, ii}) || isnumeric (atts{2, ii}))
outs = setfield (outs, atts{1, ii}, cell2mat (atts(2:end, ii)));
else
outs = setfield (outs, atts{1, ii}, atts(2:end, ii));
endif
endfor
atts = [];
endif
endif
catch
printf ("shaperead: file %s couldn't be read;\n", [ bname ".dbf" ]);
printf (" no attributes appended\n");
end_try_catch
endif
endfunction
function has_M = checkM (fidp, ft, shpbox)
has_M = true;
## Check if we do have M-values. If so, the next 3 4-byte words
## comprise the next record nr, rec length and shape type
fptr = ftell (fidp);
tmp = fread (fidp, 2, "int32", 0, "ieee-be");
tmp(3) = fread (fidp, 1, "int32");
if (tmp(1) == 2 && tmp(3) == ft)
## Looks like next record header + next shape feature type => no M
has_M = false;
shpbox.M(1) = 0;
shpbox.M(2) = 0;
endif
fseek (fidp, fptr, "bof");
endfunction
## Only check input validation. I/O is tested in shapewrite.m
%!error <arg. #2 char value should be one of> shaperead ('tst.shp', 'j');
%!error <shaperead: arg. #2 integer value out of range> shaperead ('tst.shp', 7);
%!error <illegal value for arg. #2:> shaperead ('tst.shp', 'deb')
%!error < property name expected> shaperead ('tst.shp', "ml", []);
%!error <numeric or logical value expected> shaperead ('tst.shp', 'deb', {});
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