proj3.c

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

static int lookup(const char *, const char *, char *, int);
static int equal(const char *, const char *);
static int lower(char);


char *G_database_unit_name(int plural)
{
    int n;
    static char name[256];

    switch (n = G_projection()) {
    case PROJECTION_XY:
    case PROJECTION_UTM:
    case PROJECTION_LL:
    case PROJECTION_SP:
        return G__unit_name(G__projection_units(n), plural);
    }

    if (!lookup(UNIT_FILE, plural ? "units" : "unit", name, sizeof(name)))
        strcpy(name, plural ? "units" : "unit");
    return name;
}


char *G_database_projection_name(void)
{
    int n;
    static char name[256];

    switch (n = G_projection()) {
    case PROJECTION_XY:
    case PROJECTION_UTM:
    case PROJECTION_LL:
    case PROJECTION_SP:
        return G__projection_name(n);
    }
    if (!lookup(PROJECTION_FILE, "name", name, sizeof(name)))
        strcpy(name, _("Unknown projection"));
    return name;
}


double G_database_units_to_meters_factor(void)
{
    char *unit;
    double factor;
    char buf[256];
    int n;

    static struct
    {
        char *unit;
        double factor;
    } table[] = {
        {"unit",  1.0},
        {"meter", 1.0},
        {"foot", .3048},
        {"inch", .0254},
        {NULL, 0.0}
    };

    factor = 0.0;
    if (lookup(UNIT_FILE, "meters", buf, sizeof(buf)))
        sscanf(buf, "%lf", &factor);
    if (factor <= 0.0) {
        unit = G_database_unit_name(0);
        for (n = 0; table[n].unit; n++)
            if (equal(unit, table[n].unit)) {
                factor = table[n].factor;
                break;
            }
    }
    return factor;
}

/***********************************************************************
 * G_database_datum_name(void)
 *
 * return name of datum of current database
 *
 * returns pointer to valid name if ok
 * NULL otherwise
 ***********************************************************************/


char *G_database_datum_name(void)
{
    static char name[256], params[256];
    struct Key_Value *projinfo;
    int datumstatus;

    if (lookup(PROJECTION_FILE, "datum", name, sizeof(name)))
        return name;
    else if ((projinfo = G_get_projinfo()) == NULL)
        return NULL;
    else
        datumstatus = G_get_datumparams_from_projinfo(projinfo, name, params);

    G_free_key_value(projinfo);
    if (datumstatus == 2)
        return params;
    else
        return NULL;
}

/***********************************************************************
 * G_database_ellipse_name(void)
 *
 * return name of ellipsoid of current database
 *
 * returns pointer to valid name if ok
 * NULL otherwise
 ***********************************************************************/

char *G_database_ellipse_name(void)
{
    static char name[256];

    if (!lookup(PROJECTION_FILE, "ellps", name, sizeof(name))) {
        double a, es;

        G_get_ellipsoid_parameters(&a, &es);
        sprintf(name, "a=%.16g es=%.16g", a, es);
    }

    /* strcpy (name, "Unknown ellipsoid"); */
    return name;
}

static int lookup(const char *file, const char *key, char *value, int len)
{
    char path[GPATH_MAX];

    /*
       G__file_name (path, "", file, G_mapset());
       if (access(path,0) == 0)
       return G_lookup_key_value_from_file(path, key, value, len) == 1;
     */
    G__file_name(path, "", file, "PERMANENT");
    return G_lookup_key_value_from_file(path, key, value, len) == 1;
}

static int equal(const char *a, const char *b)
{
    if (a == NULL || b == NULL)
        return a == b;
    while (*a && *b)
        if (lower(*a++) != lower(*b++))
            return 0;
    if (*a || *b)
        return 0;
    return 1;
}

static int lower(char c)
{
    if (c >= 'A' && c <= 'Z')
        c += 'a' - 'A';
    return c;
}