convert.c

Go to the documentation of this file.

#include <grass/config.h>

#ifdef HAVE_OGR
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <grass/gis.h>
#include <grass/gprojects.h>
#include <grass/glocale.h>
#include <cpl_csv.h>
#include "local_proto.h"

/* GRASS relative location of OGR co-ordinate system lookup tables */
#define CSVDIR "/etc/ogr_csv"

static void DatumNameMassage(char **);

char *GPJ_grass_to_wkt(struct Key_Value *proj_info,
                       struct Key_Value *proj_units,
                       int esri_style, int prettify)
{
    OGRSpatialReferenceH hSRS;
    char *wkt, *local_wkt;

    hSRS = GPJ_grass_to_osr(proj_info, proj_units);

    if (hSRS == NULL)
        return NULL;

    if (esri_style)
        OSRMorphToESRI(hSRS);

    if (prettify)
        OSRExportToPrettyWkt(hSRS, &wkt, 0);
    else
        OSRExportToWkt(hSRS, &wkt);

    local_wkt = G_store(wkt);
    CPLFree(wkt);
    OSRDestroySpatialReference(hSRS);
    return local_wkt;
}

OGRSpatialReferenceH GPJ_grass_to_osr(struct Key_Value * proj_info,
                                      struct Key_Value * proj_units)
{
    struct pj_info pjinfo;
    char *proj4, *proj4mod, *wkt, *modwkt, *startmod, *lastpart;
    OGRSpatialReferenceH hSRS, hSRS2;
    OGRErr errcode;
    struct gpj_datum dstruct;
    struct gpj_ellps estruct;
    size_t len;
    char *ellps, *ellpslong, *datum, *params, *towgs84, *datumlongname,
        *start, *end, *unit, *unfact, *buff;
    const char *sysname, *osrunit, *osrunfact;
    double a, es, rf;
    int haveparams = 0;

    if ((proj_info == NULL) || (proj_units == NULL))
        return NULL;

    hSRS = OSRNewSpatialReference(NULL);

    if (pj_get_kv(&pjinfo, proj_info, proj_units) < 0) {
        G_warning(_("Unable parse GRASS PROJ_INFO file"));
        return NULL;
    }

    if ((proj4 = pj_get_def(pjinfo.pj, 0)) == NULL) {
        G_warning(_("Unable get PROJ.4-style parameter string"));
        return NULL;
    }

    unit = G_find_key_value("unit", proj_units);
    unfact = G_find_key_value("meters", proj_units);
    if (unfact != NULL && (strcmp(pjinfo.proj, "ll") != 0))
        G_asprintf(&proj4mod, "%s +to_meter=%s", proj4, unfact);
    else
        proj4mod = proj4;

    if ((errcode = OSRImportFromProj4(hSRS, proj4mod)) != OGRERR_NONE) {
        G_warning(_("OGR can't parse PROJ.4-style parameter string: "
                    "%s (OGR Error code was %d)"), proj4mod, errcode);
        return NULL;
    }

    if ((errcode = OSRExportToWkt(hSRS, &wkt)) != OGRERR_NONE) {
        G_warning(_("OGR can't get WKT-style parameter string "
                    "(OGR Error code was %d)"), errcode);
        return NULL;
    }

    ellps = G_find_key_value("ellps", proj_info);
    GPJ__get_ellipsoid_params(proj_info, &a, &es, &rf);
    haveparams = GPJ__get_datum_params(proj_info, &datum, &params);

    if ((datum == NULL) || (GPJ_get_datum_by_name(datum, &dstruct) < 0)) {
        G_asprintf(&datumlongname, "unknown");
        if (ellps == NULL)
            G_asprintf(&ellps, "unnamed");
    }
    else {
        datumlongname = G_store(dstruct.longname);
        if (ellps == NULL)
            ellps = G_store(dstruct.ellps);
        GPJ_free_datum(&dstruct);
    }
    if (GPJ_get_ellipsoid_by_name(ellps, &estruct) > 0) {
        ellpslong = G_store(estruct.longname);
        DatumNameMassage(&ellpslong);
        GPJ_free_ellps(&estruct);
    }
    else
        ellpslong = G_store(ellps);

    startmod = G_strstr(wkt, "GEOGCS");
    lastpart = G_strstr(wkt, "PRIMEM");
    len = strlen(wkt) - strlen(startmod);
    wkt[len] = '\0';
    if (haveparams == 2) {
        /* Only put datum params into the WKT if they were specifically
         * specified in PROJ_INFO */
        char *paramkey, *paramvalue;

        paramkey = strtok(params, "=");
        paramvalue = params + strlen(paramkey) + 1;
        if (G_strcasecmp(paramkey, "towgs84") == 0)
            G_asprintf(&towgs84, ",TOWGS84[%s]", paramvalue);
        else
            towgs84 = "";
    }
    else
        towgs84 = "";

    sysname = OSRGetAttrValue(hSRS, "PROJCS", 0);
    if (sysname == NULL) {
        /* Not a projected co-ordinate system */
        start = "";
        end = "";
    }
    else {
        if ((strcmp(sysname, "unnamed") == 0) &&
            (G_find_key_value("name", proj_info) != NULL))
            G_asprintf(&start, "PROJCS[\"%s\",",
                       G_find_key_value("name", proj_info));
        else
            start = G_store(wkt);

        osrunit = OSRGetAttrValue(hSRS, "UNIT", 0);
        osrunfact = OSRGetAttrValue(hSRS, "UNIT", 1);

        if ((unfact == NULL) || (G_strcasecmp(osrunit, "unknown") != 0))
            end = "";
        else {
            double unfactf = atof(unfact);

            G_asprintf(&buff, ",UNIT[\"%s\",", osrunit);

            startmod = G_strstr(lastpart, buff);
            len = strlen(lastpart) - strlen(startmod);
            lastpart[len] = '\0';

            if (unit == NULL)
                G_asprintf(&unit, "unknown");
            G_asprintf(&end, ",UNIT[\"%s\",%.16g]]", unit, unfactf);
        }

    }

    G_asprintf(&modwkt,
               "%sGEOGCS[\"%s\",DATUM[\"%s\",SPHEROID[\"%s\",%.16g,%.16g]%s],%s%s",
               start, ellps, datumlongname, ellpslong, a, rf, towgs84,
               lastpart, end);

    hSRS2 = OSRNewSpatialReference(modwkt);

    OSRDestroySpatialReference(hSRS);
    G_free(modwkt);
    CPLFree(wkt);
    pj_dalloc(proj4);
    if (proj4 != proj4mod)
        G_free(proj4mod);
    G_free(datum);
    G_free(params);
    G_free(datumlongname);
    pj_free(pjinfo.pj);
    G_free(ellpslong);
    /* Other string pointers may or may not need to be freed depending
     * on sequence of execution so just leave them. */

    return hSRS2;
}

int GPJ_osr_to_grass(struct Cell_head *cellhd, struct Key_Value **projinfo,
                     struct Key_Value **projunits, OGRSpatialReferenceH hSRS,
                     int datumtrans)
{
    struct Key_Value *temp_projinfo;
    char *pszProj4 = NULL, *pszRemaining;
    char *pszProj = NULL;
    char *datum = NULL;
    struct gpj_datum dstruct;

    if (hSRS == NULL)
        goto default_to_xy;

    /* Set finder function for locating OGR csv co-ordinate system tables */
    SetCSVFilenameHook(GPJ_set_csv_loc);

    /* Hopefully this doesn't do any harm if it wasn't in ESRI format
     * to start with... */
    OSRMorphFromESRI(hSRS);

    /* -------------------------------------------------------------------- */
    /*      Set cellhd for well known coordinate systems.                   */
    /* -------------------------------------------------------------------- */
    if (!OSRIsGeographic(hSRS) && !OSRIsProjected(hSRS))
        goto default_to_xy;

    if (cellhd) {
        int bNorth;

        if (OSRIsGeographic(hSRS)) {
            cellhd->proj = PROJECTION_LL;
            cellhd->zone = 0;
        }
        else if (OSRGetUTMZone(hSRS, &bNorth) != 0) {
            cellhd->proj = PROJECTION_UTM;
            cellhd->zone = OSRGetUTMZone(hSRS, &bNorth);
            if (!bNorth)
                cellhd->zone *= -1;
        }
        else {
            cellhd->proj = PROJECTION_OTHER;
            cellhd->zone = 0;
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Get the coordinate system definition in PROJ.4 format.          */
    /* -------------------------------------------------------------------- */
    if (OSRExportToProj4(hSRS, &pszProj4) != OGRERR_NONE)
        goto default_to_xy;

    /* -------------------------------------------------------------------- */
    /*      Parse the PROJ.4 string into key/value pairs.  Do a bit of      */
    /*      extra work to "GRASSify" the result.                            */
    /* -------------------------------------------------------------------- */
    temp_projinfo = G_create_key_value();

    /* Create "local" copy of proj4 string so we can modify and free it
     * using GRASS functions */
    pszRemaining = G_store(pszProj4);
    CPLFree(pszProj4);
    pszProj4 = pszRemaining;
    while ((pszRemaining = strstr(pszRemaining, "+")) != NULL) {
        char *pszToken, *pszValue;

        pszRemaining++;

        /* Advance pszRemaining to end of this token[=value] pair */
        pszToken = pszRemaining;
        while (*pszRemaining != ' ' && *pszRemaining != '\0')
            pszRemaining++;

        if (*pszRemaining == ' ') {
            *pszRemaining = '\0';
            pszRemaining++;
        }

        /* parse token, and value */
        if (strstr(pszToken, "=") != NULL) {
            pszValue = strstr(pszToken, "=");
            *pszValue = '\0';
            pszValue++;
        }
        else
            pszValue = "defined";


        if (G_strcasecmp(pszToken, "proj") == 0) {
            /* The ll projection is known as longlat in PROJ.4 */
            if (G_strcasecmp(pszValue, "longlat") == 0)
                pszValue = "ll";

            pszProj = pszValue;
            continue;
        }

        /* Ellipsoid and datum handled separately below */
        if (G_strcasecmp(pszToken, "ellps") == 0
            || G_strcasecmp(pszToken, "a") == 0
            || G_strcasecmp(pszToken, "b") == 0
            || G_strcasecmp(pszToken, "es") == 0
            || G_strcasecmp(pszToken, "rf") == 0
            || G_strcasecmp(pszToken, "datum") == 0)
            continue;

        /* We will handle units separately */
        if (G_strcasecmp(pszToken, "to_meter") == 0
            || G_strcasecmp(pszToken, "units") == 0)
            continue;

        G_set_key_value(pszToken, pszValue, temp_projinfo);
    }

    *projinfo = G_create_key_value();

    /* -------------------------------------------------------------------- */
    /*      Derive the user name for the projection.                        */
    /* -------------------------------------------------------------------- */
    if (pszProj) {
        char path[4095];
        char name[80];

        sprintf(path, "%s/etc/projections", G_gisbase());
        if (G_lookup_key_value_from_file(path, pszProj, name, sizeof(name)) >
            0)
            G_set_key_value("name", name, *projinfo);
        else
            G_set_key_value("name", pszProj, *projinfo);

        G_set_key_value("proj", pszProj, *projinfo);
    }
    else
        G_warning(_("No projection name! Projection parameters likely to be meaningless."));


    /* -------------------------------------------------------------------- */
    /*      Find the GRASS datum name and choose parameters either          */
    /*      interactively or not.                                           */
    /* -------------------------------------------------------------------- */

    {
        const char *pszDatumNameConst = OSRGetAttrValue(hSRS, "DATUM", 0);
        struct datum_list *list, *listhead;
        char *dum1, *dum2, *pszDatumName;
        int paramspresent =
            GPJ__get_datum_params(temp_projinfo, &dum1, &dum2);

        if (pszDatumNameConst) {
            /* Need to make a new copy of the string so we don't mess
             * around with the memory inside the OGRSpatialReferenceH? */

            pszDatumName = G_store(pszDatumNameConst);
            DatumNameMassage(&pszDatumName);

            list = listhead = read_datum_table();

            while (list != NULL) {
                if (G_strcasecmp(pszDatumName, list->longname) == 0) {
                    datum = G_store(list->name);
                    break;
                }
                list = list->next;
            }
            free_datum_list(listhead);

            if (datum == NULL) {
                if (paramspresent < 2)
                    /* Only give warning if no parameters present */
                    G_warning(_("Datum <%s> not recognised by GRASS and no parameters found"),
                              pszDatumName);
            }
            else {
                G_set_key_value("datum", datum, *projinfo);

                if (paramspresent < 2) {
                    /* If no datum parameters were imported from the OSR
                     * object then we should use the set specified by datumtrans */
                    char *params, *chosenparams = NULL;
                    int paramsets;

                    paramsets =
                        GPJ_get_default_datum_params_by_name(datum, &params);

                    if (paramsets < 0)
                        G_warning(_("Datum <%s> apparently recognised by GRASS but no parameters found. "
                                   "You may want to look into this."), datum);
                    else if (datumtrans > paramsets) {

                        G_warning(_("Invalid transformation number %d; valid range is 1 to %d. "
                                   "Leaving datum transform parameters unspecified."),
                                  datumtrans, paramsets);
                        datumtrans = 0;
                    }

                    if (paramsets > 0) {
                        struct gpj_datum_transform_list *list, *old;

                        list = GPJ_get_datum_transform_by_name(datum);

                        if (list != NULL) {
                            do {
                                if (list->count == datumtrans) {
                                    chosenparams = G_store(list->params);
                                    break;
                                }
                                old = list;
                                list = list->next;
                                G_free(old);
                            } while (list != NULL);
                        }
                    }

                    if (chosenparams != NULL) {
                        char *paramkey, *paramvalue;

                        paramkey = strtok(chosenparams, "=");
                        paramvalue = chosenparams + strlen(paramkey) + 1;
                        G_set_key_value(paramkey, paramvalue, *projinfo);
                        G_free(chosenparams);
                    }

                    if (paramsets > 0)
                        G_free(params);
                }

            }
        }
    }

    /* -------------------------------------------------------------------- */
    /*   Determine an appropriate GRASS ellipsoid name if possible, or      */
    /*   else just put a and es values into PROJ_INFO                       */
    /* -------------------------------------------------------------------- */

    if ((datum != NULL) && (GPJ_get_datum_by_name(datum, &dstruct) > 0)) {
        /* Use ellps name associated with datum */
        G_set_key_value("ellps", dstruct.ellps, *projinfo);
        GPJ_free_datum(&dstruct);
        G_free(datum);
    }
    else {
        /* If we can't determine the ellipsoid from the datum, derive it
         * directly from "SPHEROID" parameters in WKT */
        const char *pszSemiMajor = OSRGetAttrValue(hSRS, "SPHEROID", 1);
        const char *pszInvFlat = OSRGetAttrValue(hSRS, "SPHEROID", 2);

        if (pszSemiMajor != NULL && pszInvFlat != NULL) {
            char *ellps = NULL;
            struct ellps_list *list, *listhead;
            double a = atof(pszSemiMajor), invflat = atof(pszInvFlat), flat;
            double es;

            /* Allow for incorrect WKT describing a sphere where InvFlat 
             * is given as 0 rather than inf */
            if (invflat > 0)
                flat = 1 / invflat;
            else
                flat = 0;

            es = flat * (2.0 - flat);

            list = listhead = read_ellipsoid_table(0);

            while (list != NULL) {
                /* Try and match a and es against GRASS defined ellipsoids;
                 * accept first one that matches. These numbers were found
                 * by trial and error and could be fine-tuned, or possibly
                 * a direct comparison of IEEE floating point values used. */
                if ((a == list->a || fabs(a - list->a) < 0.1 || fabs(1 - a / list->a) < 0.0000001) && ((es == 0 && list->es == 0) ||    /* Special case for sphere */
                                                                                                       (invflat == list->rf || fabs(invflat - list->rf) < 0.0000001))) {
                    ellps = G_store(list->name);
                    break;
                }
                list = list->next;
            }
            if (listhead != NULL)
                free_ellps_list(listhead);

            if (ellps == NULL) {
                /* If we weren't able to find a matching ellps name, set
                 * a and es values directly from WKT-derived data */
                char es_str[100];

                G_set_key_value("a", (char *)pszSemiMajor, *projinfo);

                sprintf(es_str, "%.16g", es);
                G_set_key_value("es", es_str, *projinfo);
            }
            else {
                /* else specify the GRASS ellps name for readability */
                G_set_key_value("ellps", ellps, *projinfo);
                G_free(ellps);
            }

        }

    }

    /* -------------------------------------------------------------------- */
    /*      Finally append the detailed projection parameters to the end    */
    /* -------------------------------------------------------------------- */

    {
        int i;

        for (i = 0; i < temp_projinfo->nitems; i++)
            G_set_key_value(temp_projinfo->key[i],
                            temp_projinfo->value[i], *projinfo);

        G_free_key_value(temp_projinfo);
    }

    G_free(pszProj4);

    /* -------------------------------------------------------------------- */
    /*      Set the linear units.                                           */
    /* -------------------------------------------------------------------- */
    *projunits = G_create_key_value();

    if (OSRIsGeographic(hSRS)) {
        /* We assume degrees ... someday we will be wrong! */
        G_set_key_value("unit", "degree", *projunits);
        G_set_key_value("units", "degrees", *projunits);
        G_set_key_value("meters", "1.0", *projunits);
    }
    else {
        char szFormatBuf[256];
        char *pszUnitsName = NULL;
        double dfToMeters;
        char *pszUnitsPlural, *pszStringEnd;

        dfToMeters = OSRGetLinearUnits(hSRS, &pszUnitsName);

        /* Workaround for the most obvious case when unit name is unknown */
        if ((G_strcasecmp(pszUnitsName, "unknown") == 0) &&
            (dfToMeters == 1.))
            G_asprintf(&pszUnitsName, "meter");

        G_set_key_value("unit", pszUnitsName, *projunits);

        /* Attempt at plural formation (WKT format doesn't store plural
         * form of unit name) */
        pszUnitsPlural = G_malloc(strlen(pszUnitsName) + 3);
        strcpy(pszUnitsPlural, pszUnitsName);
        pszStringEnd = pszUnitsPlural + strlen(pszUnitsPlural) - 4;
        if (G_strcasecmp(pszStringEnd, "foot") == 0) {
            /* Special case for foot - change two o's to e's */
            pszStringEnd[1] = 'e';
            pszStringEnd[2] = 'e';
        }
        else if (G_strcasecmp(pszStringEnd, "inch") == 0) {
            /* Special case for inch - add es */
            pszStringEnd[4] = 'e';
            pszStringEnd[5] = 's';
            pszStringEnd[6] = '\0';
        }
        else {
            /* For anything else add an s at the end */
            pszStringEnd[4] = 's';
            pszStringEnd[5] = '\0';
        }

        G_set_key_value("units", pszUnitsPlural, *projunits);
        G_free(pszUnitsPlural);

        sprintf(szFormatBuf, "%.16g", dfToMeters);
        G_set_key_value("meters", szFormatBuf, *projunits);

    }

    return 2;

    /* -------------------------------------------------------------------- */
    /*      Fallback to returning an ungeoreferenced definition.            */
    /* -------------------------------------------------------------------- */
  default_to_xy:
    if (cellhd != NULL) {
        cellhd->proj = PROJECTION_XY;
        cellhd->zone = 0;
    }

    *projinfo = NULL;
    *projunits = NULL;

    return 1;
}


int GPJ_wkt_to_grass(struct Cell_head *cellhd, struct Key_Value **projinfo,
                     struct Key_Value **projunits, const char *wkt,
                     int datumtrans)
{
    int retval;

    if (wkt == NULL)
        retval =
            GPJ_osr_to_grass(cellhd, projinfo, projunits, NULL, datumtrans);
    else {
        OGRSpatialReferenceH hSRS;

        /* Set finder function for locating OGR csv co-ordinate system tables */
        SetCSVFilenameHook(GPJ_set_csv_loc);

        hSRS = OSRNewSpatialReference(wkt);
        retval =
            GPJ_osr_to_grass(cellhd, projinfo, projunits, hSRS, datumtrans);
        OSRDestroySpatialReference(hSRS);
    }

    return retval;
}


/* GPJ_set_csv_loc()
 * 'finder function' for use with OGR SetCSVFilenameHook() function */

const char *GPJ_set_csv_loc(const char *name)
{
    const char *gisbase = G_gisbase();
    static char *buf = NULL;

    if (buf != NULL)
        G_free(buf);

    G_asprintf(&buf, "%s%s/%s", gisbase, CSVDIR, name);

    return buf;
}


/* The list below is only for files that use a non-standard name for a 
 * datum that is already supported in GRASS. The number of entries must be even;
 * they are all in pairs. The first one in the pair is the non-standard name;
 * the second is the GRASS name. If a name appears more than once (as for
 * European_Terrestrial_Reference_System_1989) then it means there was more
 * than one non-standard name for it that needs to be accounted for. 
 *
 * N.B. The order of these pairs is different from that in 
 * ogr/ogrfromepsg.cpp in the GDAL source tree! GRASS uses the EPSG
 * names in its WKT representation except WGS_1984 and WGS_1972 as
 * these shortened versions seem to be standard
 */

static const char *papszDatumEquiv[] = {
    "Militar_Geographische_Institute",
    "Militar_Geographische_Institut",
    "World_Geodetic_System_1984",
    "WGS_1984",
    "World_Geodetic_System_1972",
    "WGS_1972",
    "European_Terrestrial_Reference_System_89",
    "European_Terrestrial_Reference_System_1989",
    "European_Reference_System_1989",
    "European_Terrestrial_Reference_System_1989",
    "ETRS_1989",
    "European_Terrestrial_Reference_System_1989",
    "ETRS89",
    "European_Terrestrial_Reference_System_1989",
    "ETRF_1989",
    "European_Terrestrial_Reference_System_1989",
    "NZGD_2000",
    "New_Zealand_Geodetic_Datum_2000",
    "Monte_Mario_Rome",
    "Monte_Mario",
    "MONTROME",
    "Monte_Mario",
    "Campo_Inchauspe_1969",
    "Campo_Inchauspe",
    "S_JTSK_Ferro",
    "Militar_Geographische_Institut",
    "Potsdam_Datum_83",
    "Deutsches_Hauptdreiecksnetz",
    "South_American_1969",
    "South_American_Datum_1969",
    "ITRF_1992",
    "ITRF92",
    NULL
};

/************************************************************************/
/*                      OGREPSGDatumNameMassage()                       */
/*                                                                      */
/*      Massage an EPSG datum name into WMT format.  Also transform     */
/*      specific exception cases into WKT versions.                     */

/************************************************************************/

static void DatumNameMassage(char **ppszDatum)
{
    int i, j;
    char *pszDatum = *ppszDatum;

    /* -------------------------------------------------------------------- */
    /*      Translate non-alphanumeric values to underscores.               */
    /* -------------------------------------------------------------------- */
    for (i = 0; pszDatum[i] != '\0'; i++) {
        if (!(pszDatum[i] >= 'A' && pszDatum[i] <= 'Z')
            && !(pszDatum[i] >= 'a' && pszDatum[i] <= 'z')
            && !(pszDatum[i] >= '0' && pszDatum[i] <= '9')) {
            pszDatum[i] = '_';
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Remove repeated and trailing underscores.                       */
    /* -------------------------------------------------------------------- */
    for (i = 1, j = 0; pszDatum[i] != '\0'; i++) {
        if (pszDatum[j] == '_' && pszDatum[i] == '_')
            continue;

        pszDatum[++j] = pszDatum[i];
    }
    if (pszDatum[j] == '_')
        pszDatum[j] = '\0';
    else
        pszDatum[j + 1] = '\0';

    /* -------------------------------------------------------------------- */
    /*      Search for datum equivalences.  Specific massaged names get     */
    /*      mapped to OpenGIS specified names.                              */
    /* -------------------------------------------------------------------- */
    for (i = 0; papszDatumEquiv[i] != NULL; i += 2) {
        if (EQUAL(*ppszDatum, papszDatumEquiv[i])) {
            G_free(*ppszDatum);
            *ppszDatum = G_store(papszDatumEquiv[i + 1]);
            break;
        }
    }
}

#endif /* HAVE_OGR */