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

/*!
   \file read_ogr.c

   \brief Vector library - reading data (OGR format)

   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 <grass/gis.h>
#include <grass/vector.h>
#include <grass/glocale.h>

#ifdef HAVE_OGR
#include <ogr_api.h>

/*!
 * \brief Recursively read feature and add all elements to points_cache and types_cache.
 *
 * ftype : if > 0 use this type (because parts of Polygon are read as wkbLineString)
 *
 * \param Map vector map layer
 * \param[out] hGeom OGR geometry
 * \param ftype feature type
 * 
 * \return 0 OK
 * \return 1 error
 */
static int cache_feature(struct Map_info *Map, OGRGeometryH hGeom, int ftype)
{
    int line, i, np, ng, tp;
    OGRwkbGeometryType type;
    OGRGeometryH hGeom2;

    G_debug(4, "cache_feature");

    /* Alloc space */
    line = Map->fInfo.ogr.lines_num;
    if (line == Map->fInfo.ogr.lines_alloc) {
	Map->fInfo.ogr.lines_alloc += 20;
	Map->fInfo.ogr.lines =
	    (struct line_pnts **)G_realloc((void *)Map->fInfo.ogr.lines,
					   Map->fInfo.ogr.lines_alloc *
					   sizeof(struct line_pnts *));

	Map->fInfo.ogr.lines_types =
	    (int *)G_realloc(Map->fInfo.ogr.lines_types,
			     Map->fInfo.ogr.lines_alloc * sizeof(int));

	for (i = Map->fInfo.ogr.lines_num; i < Map->fInfo.ogr.lines_alloc;
	     i++)
	    Map->fInfo.ogr.lines[i] = Vect_new_line_struct();

    }
    Vect_reset_line(Map->fInfo.ogr.lines[line]);

    type = wkbFlatten(OGR_G_GetGeometryType(hGeom));

    switch (type) {
    case wkbPoint:
	G_debug(4, "Point");
	Vect_append_point(Map->fInfo.ogr.lines[line],
			  OGR_G_GetX(hGeom, 0), OGR_G_GetY(hGeom, 0),
			  OGR_G_GetZ(hGeom, 0));
	Map->fInfo.ogr.lines_types[line] = GV_POINT;
	Map->fInfo.ogr.lines_num++;
	return 0;
	break;

    case wkbLineString:
	G_debug(4, "LineString");
	np = OGR_G_GetPointCount(hGeom);
	for (i = 0; i < np; i++) {
	    Vect_append_point(Map->fInfo.ogr.lines[line],
			      OGR_G_GetX(hGeom, i), OGR_G_GetY(hGeom, i),
			      OGR_G_GetZ(hGeom, i));
	}

	if (ftype > 0) {	/* Polygon rings */
	    Map->fInfo.ogr.lines_types[line] = ftype;
	}
	else {
	    Map->fInfo.ogr.lines_types[line] = GV_LINE;
	}
	Map->fInfo.ogr.lines_num++;
	return 0;
	break;

    case wkbMultiPoint:
    case wkbMultiLineString:
    case wkbPolygon:
    case wkbMultiPolygon:
    case wkbGeometryCollection:
	ng = OGR_G_GetGeometryCount(hGeom);
	G_debug(4, "%d geoms -> next level", ng);
	if (type == wkbPolygon) {
	    tp = GV_BOUNDARY;
	}
	else {
	    tp = -1;
	}
	for (i = 0; i < ng; i++) {
	    hGeom2 = OGR_G_GetGeometryRef(hGeom, i);
	    cache_feature(Map, hGeom2, tp);
	}
	return 0;
	break;

    default:
	G_warning(_("OGR feature type %d not supported"), type);
	return 1;
	break;
    }
}

/*!
 * \brief Read next line from OGR layer. Skip empty features.
 *
 *  The action of this routine can be modified by:
 *   - Vect_read_constraint_region()
 *   - Vect_read_constraint_type()
 *   - Vect_remove_constraints()
 *
 * \param Map vector map layer
 * \param[out] line_p container used to store line points within
 * \param[out] line_c container used to store line categories within
 *
 * \return  line type
 * \return  -2 no more features (EOF)
 * \return  -1 out of memory
 */
int
V1_read_next_line_ogr(struct Map_info *Map, struct line_pnts *line_p,
		      struct line_cats *line_c)
{
    int itype;
    struct bound_box lbox, mbox;
    OGRFeatureH hFeature;
    OGRGeometryH hGeom;

    G_debug(3, "V1_read_next_line_ogr()");

    if (line_p != NULL)
	Vect_reset_line(line_p);
    if (line_c != NULL)
	Vect_reset_cats(line_c);

    if (Map->Constraint_region_flag)
	Vect_get_constraint_box(Map, &mbox);

    while (1) {
	/* Read feature to cache if necessary */
	while (Map->fInfo.ogr.lines_next == Map->fInfo.ogr.lines_num) {
	    hFeature = OGR_L_GetNextFeature(Map->fInfo.ogr.layer);

	    if (hFeature == NULL) {
		return -2;
	    }			/* no more features */

	    hGeom = OGR_F_GetGeometryRef(hFeature);
	    if (hGeom == NULL) {	/* feature without geometry */
		OGR_F_Destroy(hFeature);
		continue;
	    }

	    Map->fInfo.ogr.feature_cache_id = (int)OGR_F_GetFID(hFeature);
	    if (Map->fInfo.ogr.feature_cache_id == OGRNullFID) {
		G_warning(_("OGR feature without ID"));
	    }

	    /* Cache the feature */
	    Map->fInfo.ogr.lines_num = 0;
	    cache_feature(Map, hGeom, -1);
	    G_debug(4, "%d lines read to cache", Map->fInfo.ogr.lines_num);
	    OGR_F_Destroy(hFeature);

	    Map->fInfo.ogr.lines_next = 0;	/* next to be read from cache */
	}

	/* Read next part of the feature */
	G_debug(4, "read next cached line %d", Map->fInfo.ogr.lines_next);
	itype = Map->fInfo.ogr.lines_types[Map->fInfo.ogr.lines_next];

	/* Constraint on Type of line 
	 * Default is all of  Point, Line, Area and whatever else comes along
	 */
	if (Map->Constraint_type_flag) {
	    if (!(itype & Map->Constraint_type)) {
		Map->fInfo.ogr.lines_next++;
		continue;
	    }
	}

	/* Constraint on specified region */
	if (Map->Constraint_region_flag) {
	    Vect_line_box(Map->fInfo.ogr.lines[Map->fInfo.ogr.lines_next],
			  &lbox);

	    if (!Vect_box_overlap(&lbox, &mbox)) {
		Map->fInfo.ogr.lines_next++;
		continue;
	    }
	}

	if (line_p != NULL)
	    Vect_append_points(line_p,
			       Map->fInfo.ogr.lines[Map->fInfo.ogr.
						    lines_next], GV_FORWARD);

	if (line_c != NULL && Map->fInfo.ogr.feature_cache_id != OGRNullFID)
	    Vect_cat_set(line_c, 1, Map->fInfo.ogr.feature_cache_id);

	Map->fInfo.ogr.lines_next++;
	G_debug(4, "next line read, type = %d", itype);
	return (itype);
    }
    return -2;			/* not reached */
}

/*!
 * \brief Read next line from OGR layer.
 *
 * \param Map vector map layer
 * \param[out] line_p container used to store line points within
 * \param[out] line_c container used to store line categories within
 *
 * \return  line type
 * \return  -2 no more features (EOF)
 * \return  -1 out of memory
 */
int
V2_read_next_line_ogr(struct Map_info *Map, struct line_pnts *line_p,
		      struct line_cats *line_c)
{
    if (Map->next_line > Map->plus.n_lines)
	return -2;

    return V2_read_line_ogr(Map, line_p, line_c, Map->next_line++);
}

/*!
 * \brief Recursively descend to feature and read the part
 *
 * \param Map vector map layer
 * \param hGeom OGR geometry
 * \param offset given offset
 * \param[out] Points container used to store line pointes within
 *
 * \return 0 OK
 * \return 1 error
 */
static int read_line(const struct Map_info *Map, OGRGeometryH hGeom, long offset,
		     struct line_pnts *Points)
{
    int i, nPoints;
    int eType;
    OGRGeometryH hGeom2;

    /* Read coors if hGeom is a simple element (wkbPoint, wkbLineString) otherwise
     * descend to geometry specified by offset[offset] */

    G_debug(4, "read_line() offset = %ld", offset);

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

    switch (eType) {
    case wkbPoint:
	G_debug(4, "Point");
	Vect_append_point(Points, OGR_G_GetX(hGeom, 0), OGR_G_GetY(hGeom, 0),
			  OGR_G_GetZ(hGeom, 0));
	return 0;
	break;

    case wkbLineString:
	G_debug(4, "LineString");
	nPoints = OGR_G_GetPointCount(hGeom);
	for (i = 0; i < nPoints; i++) {
	    Vect_append_point(Points, OGR_G_GetX(hGeom, i),
			      OGR_G_GetY(hGeom, i), OGR_G_GetZ(hGeom, i));
	}
	return 0;
	break;

    case wkbPolygon:
    case wkbMultiPoint:
    case wkbMultiLineString:
    case wkbMultiPolygon:
    case wkbGeometryCollection:
	G_debug(4, " more geoms -> part %d", Map->fInfo.ogr.offset[offset]);
	hGeom2 = OGR_G_GetGeometryRef(hGeom, Map->fInfo.ogr.offset[offset]);
	return (read_line(Map, hGeom2, offset + 1, Points));
	break;

    default:
	G_warning(_("OGR feature type %d not supported"), eType);
	break;
    }
    return 1;
}

/*!
 * \brief Read line from layer on given offset.
 *
 * \param Map vector map layer
 * \param[out] line_p container used to store line points within
 * \param[out] line_c container used to store line categories within
 * \param line line id
 *
 * \return line type
 * \return -2 end of table (last row)
 * \return -1 out of memory
 */
int
V2_read_line_ogr(struct Map_info *Map, struct line_pnts *line_p,
		 struct line_cats *line_c, int line)
{
    int node;
    int offset;
    long FID;
    struct P_line *Line;
    struct P_node *Node;
    OGRGeometryH hGeom;

    G_debug(4, "V2_read_line_ogr() line = %d", line);

    if (line_p != NULL)
	Vect_reset_line(line_p);
    if (line_c != NULL)
	Vect_reset_cats(line_c);

    Line = Map->plus.Line[line];
    offset = (int)Line->offset;

    if (Line->type == GV_CENTROID) {
	G_debug(4, "Centroid");
	node = Line->N1;
	Node = Map->plus.Node[node];

	/* coordinates */
	if (line_p != NULL) {
	    Vect_append_point(line_p, Node->x, Node->y, 0.0);
	}

	/* category */
	if (line_c != NULL) {
	    /* cat = FID and offset = FID for centroid */
	    Vect_cat_set(line_c, 1, (int)offset);
	}

	return (GV_CENTROID);
    }
    else {
	FID = Map->fInfo.ogr.offset[offset];
	G_debug(4, "  FID = %ld", FID);

	/* coordinates */
	if (line_p != NULL) {
	    /* Read feature to cache if necessary */
	    if (Map->fInfo.ogr.feature_cache_id != FID) {
		G_debug(4, "Read feature (FID = %ld) to cache.", FID);
		if (Map->fInfo.ogr.feature_cache) {
		    OGR_F_Destroy(Map->fInfo.ogr.feature_cache);
		}
		Map->fInfo.ogr.feature_cache =
		    OGR_L_GetFeature(Map->fInfo.ogr.layer, FID);
		if (Map->fInfo.ogr.feature_cache == NULL) {
		    G_fatal_error(_("Unable to get feature geometry, FID %ld"),
				  FID);
		}
		Map->fInfo.ogr.feature_cache_id = FID;
	    }

	    hGeom = OGR_F_GetGeometryRef(Map->fInfo.ogr.feature_cache);
	    if (hGeom == NULL) {
		G_fatal_error(_("Unable to get feature geometry, FID %ld"),
			      FID);
	    }

	    read_line(Map, hGeom, Line->offset + 1, line_p);
	}

	/* category */
	if (line_c != NULL) {
	    Vect_cat_set(line_c, 1, (int)FID);
	}

	return Line->type;
    }

    return -2;			/* not reached */
}

#endif