Geografic-Information-System/lib/vector/Vlib/build_ogr.c

/*!
   \file lib/vector/Vlib/build_ogr.c

   \brief Vector library - Building topology for OGR

   Higher level functions for reading/writing/manipulating vectors.

   (C) 2001-2009 by the GRASS Development Team

   This program is free software under the 
   GNU General Public License (>=v2). 
   Read the file COPYING that comes with GRASS
   for details.

   \author Radim Blazek, Piero Cavalieri
 */

#include <grass/config.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <grass/gis.h>
#include <grass/vector.h>
#include <grass/glocale.h>

/* 
 *   Line offset is
 *      - centroids   : FID
 *      - other types : index of the first record (which is FID) in offset array.
 *
 *   Category: FID, not all layer have FID, OGRNullFID is defined (5/2004) as -1, so FID should be only >= 0
 *
 */

#ifdef HAVE_OGR
#include <ogr_api.h>

/* 
 *  This structure keeps info about geometry parts above current geometry, path to curent geometry in the 
 *  feature. First 'part' number however is feature Id 
 */
typedef struct
{
    int *part;
    int a_parts;
    int n_parts;
} GEOM_PARTS;

/* Init parts */
static void init_parts(GEOM_PARTS * parts)
{
    parts->part = NULL;
    parts->a_parts = parts->n_parts = 0;
}

/* Reset parts */
static void reset_parts(GEOM_PARTS * parts)
{
    parts->n_parts = 0;
}

/* Free parts */
static void free_parts(GEOM_PARTS * parts)
{
    G_free(parts->part);
    parts->a_parts = parts->n_parts = 0;
}

/* Add new part number to parts */
static void add_part(GEOM_PARTS * parts, int part)
{
    if (parts->a_parts == parts->n_parts) {
	parts->a_parts += 10;
	parts->part =
	    (int *)G_realloc((void *)parts->part,
			     parts->a_parts * sizeof(int));
    }
    parts->part[parts->n_parts] = part;
    parts->n_parts++;
}

/* Remove last part */
static void del_part(GEOM_PARTS * parts)
{
    parts->n_parts--;
}

/* Add parts to offset */
static void add_parts_to_offset(struct Map_info *Map, GEOM_PARTS * parts)
{
    int i, j;

    if (Map->fInfo.ogr.offset_num + parts->n_parts >=
	Map->fInfo.ogr.offset_alloc) {
	Map->fInfo.ogr.offset_alloc += parts->n_parts + 1000;
	Map->fInfo.ogr.offset = (int *)G_realloc(Map->fInfo.ogr.offset,
						 Map->fInfo.ogr.offset_alloc *
						 sizeof(int));
    }
    j = Map->fInfo.ogr.offset_num;
    for (i = 0; i < parts->n_parts; i++) {
	G_debug(4, "add offset %d", parts->part[i]);
	Map->fInfo.ogr.offset[j] = parts->part[i];
	j++;
    }
    Map->fInfo.ogr.offset_num += parts->n_parts;
}

/* add line to support structures */
static int add_line(struct Map_info *Map, int type, struct line_pnts *Points,
		    int FID, GEOM_PARTS * parts)
{
    int line;
    struct Plus_head *plus;
    long offset;
    struct bound_box box;

    plus = &(Map->plus);

    if (type != GV_CENTROID) {
	offset = Map->fInfo.ogr.offset_num;	/* beginning in the offset array */
    }
    else {
	/* TODO : could be used to statore category ? */
	offset = FID;		/* because centroids are read from topology, not from layer */
    }
    G_debug(4, "Register line: FID = %d offset = %ld", FID, offset);
    line = dig_add_line(plus, type, Points, offset);
    G_debug(4, "Line registered with line = %d", line);

    /* Set box */
    dig_line_box(Points, &box);
    if (line == 1)
	Vect_box_copy(&(plus->box), &box);
    else
	Vect_box_extend(&(plus->box), &box);

    if (type != GV_BOUNDARY) {
	dig_cidx_add_cat(plus, 1, (int)FID, line, type);
    }
    else {
	dig_cidx_add_cat(plus, 0, 0, line, type);
    }

    if (type != GV_CENTROID)	/* because centroids are read from topology, not from layer */
	add_parts_to_offset(Map, parts);

    return line;
}

/* Recursively add geometry to topology */
static int add_geometry(struct Map_info *Map, OGRGeometryH hGeom, int FID,
			GEOM_PARTS * parts)
{
    struct Plus_head *plus;
    int i, ret;
    int line;
    int area, isle, outer_area = 0;
    int lines[1];
    static struct line_pnts **Points = NULL;
    static int alloc_points = 0;
    struct bound_box box;
    struct P_line *Line;
    double area_size, x, y;
    int eType, nRings, iPart, nParts, nPoints;
    OGRGeometryH hGeom2, hRing;

    G_debug(4, "add_geometry() FID = %d", FID);
    plus = &(Map->plus);

    if (!Points) {
	alloc_points = 1;
	Points = (struct line_pnts **)G_malloc(sizeof(struct line_pnts *));
	Points[0] = Vect_new_line_struct();
    }
    Vect_reset_line(Points[0]);

    eType = wkbFlatten(OGR_G_GetGeometryType(hGeom));
    G_debug(4, "OGR type = %d", eType);

    switch (eType) {
    case wkbPoint:
	G_debug(4, "Point");
	Vect_append_point(Points[0], OGR_G_GetX(hGeom, 0),
			  OGR_G_GetY(hGeom, 0), OGR_G_GetZ(hGeom, 0));
	add_line(Map, GV_POINT, Points[0], FID, parts);
	break;

    case wkbLineString:
	G_debug(4, "LineString");
	nPoints = OGR_G_GetPointCount(hGeom);
	for (i = 0; i < nPoints; i++) {
	    Vect_append_point(Points[0],
			      OGR_G_GetX(hGeom, i), OGR_G_GetY(hGeom, i),
			      OGR_G_GetZ(hGeom, i));
	}
	add_line(Map, GV_LINE, Points[0], FID, parts);
	break;

    case wkbPolygon:
	G_debug(4, "Polygon");

	nRings = OGR_G_GetGeometryCount(hGeom);
	G_debug(4, "Number of rings: %d", nRings);

	/* Alloc space for islands */
	if (nRings >= alloc_points) {
	    Points = (struct line_pnts **)G_realloc((void *)Points,
						    nRings *
						    sizeof(struct line_pnts
							   *));
	    for (i = alloc_points; i < nRings; i++) {
		Points[i] = Vect_new_line_struct();
	    }
	}

	for (iPart = 0; iPart < nRings; iPart++) {
	    hRing = OGR_G_GetGeometryRef(hGeom, iPart);
	    nPoints = OGR_G_GetPointCount(hRing);
	    G_debug(4, "  ring %d : nPoints = %d", iPart, nPoints);


	    Vect_reset_line(Points[iPart]);
	    for (i = 0; i < nPoints; i++) {
		Vect_append_point(Points[iPart],
				  OGR_G_GetX(hRing, i), OGR_G_GetY(hRing, i),
				  OGR_G_GetZ(hRing, i));
	    }

	    /* register line */
	    add_part(parts, iPart);
	    line = add_line(Map, GV_BOUNDARY, Points[iPart], FID, parts);
	    del_part(parts);

	    /* add area (each inner ring is also area) */
	    dig_line_box(Points[iPart], &box);
	    dig_find_area_poly(Points[iPart], &area_size);

	    if (area_size > 0)	/* clockwise */
		lines[0] = line;
	    else
		lines[0] = -line;

	    area = dig_add_area(plus, 1, lines);
	    dig_area_set_box(plus, area, &box);

	    /* Each area is also isle */
	    lines[0] = -lines[0];	/* island is counter clockwise */

	    isle = dig_add_isle(plus, 1, lines);
	    dig_isle_set_box(plus, isle, &box);

	    if (iPart == 0) {	/* outer ring */
		outer_area = area;
	    }
	    else {		/* inner ring */
		struct P_isle *Isle;

		Isle = plus->Isle[isle];
		Isle->area = outer_area;

		dig_area_add_isle(plus, outer_area, isle);
	    }
	}

	/* create virtual centroid */
	ret =
	    Vect_get_point_in_poly_isl((const struct line_pnts *) Points[0],
				       (const struct line_pnts **) Points + 1, nRings - 1,
				       &x, &y);
	if (ret < -1) {
	    G_warning(_("Unable to calculate centroid for area %d"),
		      outer_area);
	}
	else {
	    struct P_area *Area;

	    G_debug(4, "  Centroid: %f, %f", x, y);
	    Vect_reset_line(Points[0]);
	    Vect_append_point(Points[0], x, y, 0.0);
	    line = add_line(Map, GV_CENTROID, Points[0], FID, parts);
	    dig_line_box(Points[0], &box);
	    dig_line_set_box(plus, line, &box);

	    Line = plus->Line[line];
	    Line->left = outer_area;

	    /* register centroid to area */
	    Area = plus->Area[outer_area];
	    Area->centroid = line;
	}
	break;

    case wkbMultiPoint:
    case wkbMultiLineString:
    case wkbMultiPolygon:
    case wkbGeometryCollection:
	nParts = OGR_G_GetGeometryCount(hGeom);
	G_debug(4, "%d geoms -> next level", nParts);
	for (i = 0; i < nParts; i++) {
	    add_part(parts, i);
	    hGeom2 = OGR_G_GetGeometryRef(hGeom, i);
	    add_geometry(Map, hGeom2, FID, parts);
	    del_part(parts);
	}
	break;

    default:
	G_warning(_("OGR feature type %d not supported"), eType);
	break;
    }

    return 0;
}

/*!
   \brief Build pseudo-topology for OGR layer

   \param Map pointer to Map_info structure
   \param build build level (GV_BUILD_NONE and GV_BUILD_ALL currently supported)

   \return 1 on success
   \return 0 on error
 */
int Vect_build_ogr(struct Map_info *Map, int build)
{
    int iFeature, count, FID;
    struct Plus_head *plus;
    
    GEOM_PARTS parts;
    OGRFeatureH hFeature;
    OGRGeometryH hGeom;

    G_debug(1, "Vect_build_ogr(): dsn=%s layer=%s, build=%d",
	    Map->fInfo.ogr.dsn, Map->fInfo.ogr.layer_name, build);
    
    if (build != GV_BUILD_ALL && build != GV_BUILD_NONE) {
	G_warning(_("Partial build for OGR is not supported"));
	return 0;
    }

    plus = &(Map->plus);
    if (build == plus->built)
	return 1;		/* do nothing */
    
    /* TODO move this init to better place (Vect_open_ ?), because in theory build may be reused on level2 */
    G_free((void *) Map->fInfo.ogr.offset);
    Map->fInfo.ogr.offset = NULL;
    Map->fInfo.ogr.offset_num = 0;
    Map->fInfo.ogr.offset_alloc = 0;

    /* test layer capabilities */
    if (!OGR_L_TestCapability(Map->fInfo.ogr.layer, OLCRandomRead)) {
	G_warning(_("Random read is not supported by OGR for this layer, "
		    "unable to build topology"));
	return 0;
    }

    /* initialize data structures */
    init_parts(&parts);

    /* Check if upgrade or downgrade */
    if (build < plus->built) {	/* lower level request, currently only GV_BUILD_NONE */
	dig_free_plus_areas(plus);
	dig_spidx_free_areas(plus);
	dig_free_plus_isles(plus);
	dig_spidx_free_isles(plus);
	
	dig_free_plus_nodes(plus);
	dig_spidx_free_nodes(plus);
	dig_free_plus_lines(plus);
	dig_spidx_free_lines(plus);
    }
    else {
	/* Note: Do not use OGR_L_GetFeatureCount (it may scan all features) */
	OGR_L_ResetReading(Map->fInfo.ogr.layer);
	count = iFeature = 0;
	while ((hFeature = OGR_L_GetNextFeature(Map->fInfo.ogr.layer)) != NULL) {
	    iFeature++;
	    count++;
	    
	    G_debug(3, "   Feature %d", iFeature);
	    
	    hGeom = OGR_F_GetGeometryRef(hFeature);
	    if (hGeom == NULL) {
		G_warning(_("Feature %d without geometry ignored"), iFeature);
		OGR_F_Destroy(hFeature);
		continue;
	    }
	    
	    FID = (int)OGR_F_GetFID(hFeature);
	    if (FID == OGRNullFID) {
		G_warning(_("OGR feature %d without ID ignored"), iFeature);
		OGR_F_Destroy(hFeature);
		continue;
	    }
	    G_debug(4, "    FID = %d", FID);
	    
	    reset_parts(&parts);
	    add_part(&parts, FID);
	    add_geometry(Map, hGeom, FID, &parts);
	    
	    OGR_F_Destroy(hFeature);
	}				/* while */
    }

    free_parts(&parts);
    
    Map->plus.built = build;
    
    return 1;
}
#endif