read_ogr.c

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

   \brief Vector library - reading data (OGR format)

   Higher level functions for reading/writing/manipulating vectors.

   (C) 2001-2011 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
   \author Martin Landa <landa.martin gmail.com>
 */

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

#ifdef HAVE_OGR
#include <ogr_api.h>

static int cache_feature(struct Map_info *, OGRGeometryH, int);
static int read_line(const struct Map_info *, OGRGeometryH, long,
                     struct line_pnts *);
static int get_line_type(const struct Map_info *, long);
static int read_next_line_ogr(struct Map_info *, struct line_pnts *,
                              struct line_cats *, int);
#endif

/*!
  \brief Read next feature from OGR layer.
  Skip empty features (level 1 without topology).
  
  This function implements sequential access.
  
  The action of this routine can be modified by:
   - Vect_read_constraint_region()
   - Vect_read_constraint_type()
   - Vect_remove_constraints()
  
  \param Map pointer to Map_info structure
  \param[out] line_p container used to store line points within
  \param[out] line_c container used to store line categories within
  
  \return feature 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)
{
#ifdef HAVE_OGR
    return read_next_line_ogr(Map, line_p, line_c, FALSE);
#else
    G_fatal_error(_("GRASS is not compiled with OGR support"));
    return -1;
#endif
}

/*!
  \brief Read next feature from OGR layer on topological level.

  This function implements sequential access.

  \param Map pointer to Map_info structure
  \param[out] line_p container used to store line points within
  (pointer to line_pnts struct)
  \param[out] line_c container used to store line categories within
  (pointer to line_cats struct)
  
  \return feature type
  \return -2 no more features (EOF)
  \return -1 on failure
*/
int V2_read_next_line_ogr(struct Map_info *Map, struct line_pnts *line_p,
                          struct line_cats *line_c)
{
#ifdef HAVE_OGR
    int line, ret;
    struct P_line *Line;
    struct bound_box lbox, mbox;

    G_debug(3, "V2_read_next_line_ogr()");
    
    if (Map->constraint.region_flag)
        Vect_get_constraint_box(Map, &mbox);
    
    while(TRUE) {
        line = Map->next_line;
        
        if (Map->next_line > Map->plus.n_lines)
            return -2; /* nothing to read */
        
        Map->next_line++;
        Line = Map->plus.Line[line];
        if (Line == NULL) {     /* skip dead features */
            continue;
        }

        if (Map->constraint.type_flag) {
            /* skip feature by type */
            if (!(Line->type & Map->constraint.type))
                continue;
        }

        if (Line->type == GV_CENTROID) {
            G_debug(4, "Centroid");
            
            if (line_p != NULL) {
                int i, found;
                struct bound_box box;
                struct boxlist list;
                struct P_topo_c *topo = (struct P_topo_c *)Line->topo;
                
                /* get area bbox */
                Vect_get_area_box(Map, topo->area, &box);
                /* search in spatial index for centroid with area bbox */
                dig_init_boxlist(&list, TRUE);
                Vect_select_lines_by_box(Map, &box, Line->type, &list);
                
                found = 0;
                for (i = 0; i < list.n_values; i++) {
                    if (list.id[i] == line) {
                        found = i;
                        break;
                    }
                }
                
                Vect_reset_line(line_p);
                Vect_append_point(line_p, list.box[found].E, list.box[found].N, 0.0);
            }
            if (line_c != NULL) {
                /* cat = FID and offset = FID for centroid */
                Vect_reset_cats(line_c);
                Vect_cat_set(line_c, 1, (int) Line->offset);
            }

            ret = GV_CENTROID;
        }
        else {
            ret = read_next_line_ogr(Map, line_p, line_c, TRUE);
        }

        if (line_p && Map->constraint.region_flag) {
            /* skip feature by region */
            Vect_line_box(line_p, &lbox);
            if (!Vect_box_overlap(&lbox, &mbox))
                continue;
        }
        
        /* skip feature by field ignored */
                
        return ret;
    }
#else
    G_fatal_error(_("GRASS is not compiled with OGR support"));
    return -1;
#endif
}

/*!
  \brief Read feature from OGR layer at given offset (level 1 without topology)
  
  This function implements random access on level 1.

  \param Map pointer to Map_info structure 
  \param[out] line_p container used to store line points within
  (pointer line_pnts struct)
  \param[out] line_c container used to store line categories within
  (pointer line_cats struct)
  \param offset given offset 
  
  \return line type
  \return 0 dead line
  \return -2 no more features
  \return -1 on failure
*/
int V1_read_line_ogr(struct Map_info *Map,
                     struct line_pnts *line_p, struct line_cats *line_c, off_t offset)
{
#ifdef HAVE_OGR
    long fid;
    int type;
    OGRGeometryH hGeom;

    struct Format_info_ogr *ogr_info;
    
    ogr_info = &(Map->fInfo.ogr);
    G_debug(3, "V1_read_line_ogr(): offset = %lu offset_num = %lu",
            (long) offset, (long) ogr_info->offset.array_num);

    if (offset >= ogr_info->offset.array_num)
        return -2; /* nothing to read */
    
    if (line_p != NULL)
        Vect_reset_line(line_p);
    if (line_c != NULL)
        Vect_reset_cats(line_c);

    fid = ogr_info->offset.array[offset];
    G_debug(4, "  fid = %ld", fid);
    
    /* coordinates */
    if (line_p != NULL) {
        /* read feature to cache if necessary */
        if (ogr_info->cache.fid != fid) {
            G_debug(4, "Read feature (fid = %ld) to cache", fid);
            if (ogr_info->feature_cache) {
                OGR_F_Destroy(ogr_info->feature_cache);
            }
            ogr_info->feature_cache =
                OGR_L_GetFeature(ogr_info->layer, fid);
            if (ogr_info->feature_cache == NULL) {
                G_warning(_("Unable to get feature geometry, fid %ld"),
                          fid);
                return -1;
            }
            ogr_info->cache.fid = fid;
        }
        
        hGeom = OGR_F_GetGeometryRef(ogr_info->feature_cache);
        if (hGeom == NULL) {
            G_warning(_("Unable to get feature geometry, fid %ld"),
                      fid);
            return -1;
        }
        
        type = read_line(Map, hGeom, offset + 1, line_p);
    }
    else {
        type = get_line_type(Map, fid);
    }

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

    return type;
#else
    G_fatal_error(_("GRASS is not compiled with OGR support"));
    return -1;
#endif
}

#ifdef HAVE_OGR
/*!
  \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 pointer to Map_info structure
  \param[out] hGeom OGR geometry
  \param ftype feature type
  
  \return 0 on success
  \return 1 on error
*/
int cache_feature(struct Map_info *Map, OGRGeometryH hGeom, int ftype)
{
    int line, i, np, ng, tp;

    struct Format_info_ogr *ogr_info;

    OGRwkbGeometryType type;
    OGRGeometryH hGeom2;

    G_debug(4, "cache_feature() ftype = %d", ftype);

    ogr_info = &(Map->fInfo.ogr);
    
    /* alloc space in lines cache */
    line = ogr_info->cache.lines_num;
    if (line == ogr_info->cache.lines_alloc) {
        ogr_info->cache.lines_alloc += 1;
        ogr_info->cache.lines =
            (struct line_pnts **)G_realloc((void *)ogr_info->cache.lines,
                                           ogr_info->cache.lines_alloc *
                                           sizeof(struct line_pnts *));

        ogr_info->cache.lines_types =
            (int *)G_realloc(ogr_info->cache.lines_types,
                             ogr_info->cache.lines_alloc * sizeof(int));

        for (i = ogr_info->cache.lines_num; i < ogr_info->cache.lines_alloc; i++)
            ogr_info->cache.lines[i] = Vect_new_line_struct();
    }
    Vect_reset_line(ogr_info->cache.lines[line]);

    type = wkbFlatten(OGR_G_GetGeometryType(hGeom));

    switch (type) {
    case wkbPoint:
        G_debug(4, "Point");
        Vect_append_point(ogr_info->cache.lines[line],
                          OGR_G_GetX(hGeom, 0), OGR_G_GetY(hGeom, 0),
                          OGR_G_GetZ(hGeom, 0));
        ogr_info->cache.lines_types[line] = GV_POINT;
        ogr_info->cache.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(ogr_info->cache.lines[line],
                              OGR_G_GetX(hGeom, i), OGR_G_GetY(hGeom, i),
                              OGR_G_GetZ(hGeom, i));
        }

        if (ftype > 0) {        /* Polygon rings */
            ogr_info->cache.lines_types[line] = ftype;
        }
        else {
            ogr_info->cache.lines_types[line] = GV_LINE;
        }
        ogr_info->cache.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;
    }
}

int read_next_line_ogr(struct Map_info *Map, struct line_pnts *line_p,
                       struct line_cats *line_c, int ignore_constraint)
{
    int itype;
    struct bound_box lbox, mbox;
    OGRFeatureH hFeature;
    OGRGeometryH hGeom;

    struct Format_info_ogr *ogr_info;

    G_debug(3, "V1_read_next_line_ogr()");

    if (Map->constraint.region_flag && !ignore_constraint)
        Vect_get_constraint_box(Map, &mbox);

    ogr_info = &(Map->fInfo.ogr);
    while (TRUE) {
        /* reset data structures */
        if (line_p != NULL)
            Vect_reset_line(line_p);
        if (line_c != NULL)
            Vect_reset_cats(line_c);
    
        /* read feature to cache if necessary */
        while (ogr_info->cache.lines_next == ogr_info->cache.lines_num) {
            hFeature = OGR_L_GetNextFeature(ogr_info->layer);
            if (hFeature == NULL) {
                return -2;              /* nothing to read */
            }                   

            hGeom = OGR_F_GetGeometryRef(hFeature);
            if (hGeom == NULL) {        /* skip feature without geometry */
                G_warning(_("Feature without geometry. Skipped."));
                OGR_F_Destroy(hFeature);
                continue;
            }

            /* cache OGR feature */
            ogr_info->cache.fid = (int)OGR_F_GetFID(hFeature);
            if (ogr_info->cache.fid == OGRNullFID) {
                G_warning(_("OGR feature without ID"));
            }

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

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

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

        if (Map->constraint.type_flag && !ignore_constraint) {
            /* skip feature by type */
            if (!(itype & Map->constraint.type)) {
                ogr_info->cache.lines_next++;
                continue;
            }
        }

        if (Map->constraint.region_flag && !ignore_constraint) {
            /* skip feature by region */
            Vect_line_box(ogr_info->cache.lines[ogr_info->cache.lines_next],
                          &lbox);
            
            if (!Vect_box_overlap(&lbox, &mbox)) {
                ogr_info->cache.lines_next++;
                continue;
            }
        }
        
        /* skip feature by field - ignored */
        
        if (line_p != NULL)
            Vect_append_points(line_p,
                               ogr_info->cache.lines[ogr_info->cache.lines_next], GV_FORWARD);

        if (line_c != NULL && ogr_info->cache.fid != OGRNullFID)
            Vect_cat_set(line_c, 1, ogr_info->cache.fid);

        ogr_info->cache.lines_next++;
        G_debug(4, "next line read, type = %d", itype);
        
        return itype;
    }

    return -1;                  /* not reached */
}

/*!
  \brief Recursively descend to feature and read the part
  
  \param Map pointer to Map_info structure
  \param hGeom OGR geometry
  \param offset given offset
  \param[out] Points container used to store line pointes within
  
  \return feature type
  \return -1 on error
*/
int read_line(const struct Map_info *Map, OGRGeometryH hGeom, long offset,
              struct line_pnts *Points)
{
    int i, nPoints;
    int eType, line;
    
    const struct Format_info_ogr *ogr_info;
    
    OGRGeometryH hGeom2;

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

    ogr_info = &(Map->fInfo.ogr);
    
    eType = wkbFlatten(OGR_G_GetGeometryType(hGeom));
    G_debug(4, "OGR geometry type: %d", eType);
    
    switch (eType) {
    case wkbPoint:
        G_debug(4, "\t->Point");
        if (Points) {
            Vect_append_point(Points, OGR_G_GetX(hGeom, 0), OGR_G_GetY(hGeom, 0),
                              OGR_G_GetZ(hGeom, 0));
        }
        return GV_POINT;
        break;

    case wkbLineString:
        G_debug(4, "\t->LineString");   
        if (Points) {
            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 GV_LINE;
        break;

    case wkbPolygon:
    case wkbMultiPoint:
    case wkbMultiLineString:
    case wkbMultiPolygon:
    case wkbGeometryCollection:
        G_debug(4, "\t->more geoms -> part %d", ogr_info->offset.array[offset]);
        hGeom2 = OGR_G_GetGeometryRef(hGeom, ogr_info->offset.array[offset]);
        line = read_line(Map, hGeom2, offset + 1, Points);
        if (eType == wkbPolygon || eType == wkbMultiPolygon)
            return GV_BOUNDARY;
        if (eType == wkbMultiPoint)
            return GV_POINT;
        if (eType == wkbMultiLineString)
            return GV_LINE;
        return line;
        break;

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

    return -1;
}

/*!
  \brief Recursively descend to feature and read the part
  
  \param Map pointer to Map_info structure
  \param hGeom OGR geometry
  \param offset given offset
  \param[out] Points container used to store line pointes within
  
  \return feature type
  \return -1 on error
*/
int get_line_type(const struct Map_info *Map, long fid)
{
    int eType;

    const struct Format_info_ogr *ogr_info;
    
    OGRFeatureH hFeat;
    OGRGeometryH hGeom;

    G_debug(4, "get_line_type() fid = %ld", fid);

    ogr_info = &(Map->fInfo.ogr);
    
    hFeat = OGR_L_GetFeature(ogr_info->layer, fid);
    if (hFeat == NULL)
        return -1;

    hGeom = OGR_F_GetGeometryRef(hFeat);
    if (hGeom == NULL)
        return -1;
    
    eType = wkbFlatten(OGR_G_GetGeometryType(hGeom));

    OGR_F_Destroy(hFeat);

    G_debug(4, "OGR Geometry of type: %d", eType);

    switch (eType) {
    case wkbPoint:
    case wkbMultiPoint:
        return GV_POINT;
        break;
        
    case wkbLineString:
    case wkbMultiLineString:
        return GV_LINE;
        break;

    case wkbPolygon:
    case wkbMultiPolygon:
    case wkbGeometryCollection:
        return GV_BOUNDARY;
        break;

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

    return -1;
}
#endif