OVCCoordenadas web service
Author: Ángel Delgado Panadero
Description: Retrieve spatial coordinates of urban properties.

CatastRo provides an R interface to the OVCCoordenadas web service from the Sede electrónica del Catastro.

This service retrieves the spatial coordinates of an urban property. You do not need to be the owner to get the information. You only need to know the cadastral reference of the property. Although the cadastral reference is the only required argument, providing the address can improve results and help avoid errors.

The service can also obtain the cadastral reference of an urban property from longitude and latitude. It allows you to choose the spatial reference system (SRS, also known as CRS) used to express the coordinates.

The service also handles cases where the exact location of the registered urban property is unknown. In such cases, it returns all properties located within a 50-meter square around the given point.

The documentation for this service is available here.

These functions use the `catr_ovc_get_*()` prefix and return tibbles from the tibble package.

## CatastRo API

The OVCCoordenadas web service can be accessed using the following functions:

- `catr_ovc_get_rccoor()`
- `catr_ovc_get_rccoor_distancia()`
- `catr_ovc_get_cpmrc()`

## Reverse geocoding cadastral references

`catr_ovc_get_rccoor()` takes the coordinates (`lat` and `lon`) and the spatial reference system (`srs`) used to express them. It returns a tibble with the cadastral reference of the property at that spatial point, including other information such as the address (town, street and number).

    library(CatastRo)

    result <- catr_ovc_get_rccoor(
      lat = 38.6196566583596,
      lon = -3.45624183836806,
      srs = "4230"
    )

    knitr::kable(result)

refcat | address | pc.pc1 | pc.pc2 | geo.xcen | geo.ycen | geo.srs | ldt
--- | --- | --- | --- | --- | --- | --- | ---
13077A01800039 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL) | 13077A0 | 1800039 | -3.456242 | 38.61966 | EPSG:4230 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL)

This function accepts the following values for the `srs` argument:

    data(catr_srs_values)

    # OVC valid codes.
    library(dplyr)

    catr_srs_values |>
      filter(ovc_service == TRUE) |>
      select(SRS, Description) |>
      knitr::kable()

SRS | Description
--- | ---
4230 | Geográficas en ED 50
4258 | Geográficas en ETRS89
4326 | Geográficas en WGS 80
23029 | UTM huso 29N en ED50
23030 | UTM huso 30N en ED50
23031 | UTM huso 31N en ED50
25829 | UTM huso 29N en ETRS89
25830 | UTM huso 30N en ETRS89
25831 | UTM huso 31N en ETRS89
32627 | UTM huso 27N en WGS 84
32628 | UTM huso 28N en WGS 84
32629 | UTM huso 29N en WGS 84
32630 | UTM huso 30N en WGS 84
32631 | UTM huso 31N en WGS 84

It is also possible to get all cadastral references within a 50-meter square centered on the coordinates `lat` and `lon` using the function `catr_ovc_get_rccoor_distancia()`.

    catr_ovc_get_rccoor_distancia(
      lat = 40.96002,
      lon = -5.663408,
      srs = "4230"
    ) |>
      knitr::kable()

geo.xcen | geo.ycen | geo.srs | refcat | address | cmun_ine | pc.pc1 | pc.pc2 | dt.loine.cp | dt.loine.cm | dt.lourb.dir.cv | dt.lourb.dir.pnp | ldt | dis
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
-5.663408 | 40.96002 | EPSG:4230 | 5877501TL7357F | AV REYES DE ESPAÑA 1 SALAMANCA (SALAMANCA) | 37274 | 5877501 | TL7357F | 37 | 274 | 643 | 1 | AV REYES DE ESPAÑA 1 SALAMANCA (SALAMANCA) | 21.81
-5.663408 | 40.96002 | EPSG:4230 | 5778706TL7357H | AV REYES DE ESPAÑA 2 N2-4 SALAMANCA (SALAMANCA) | 37274 | 5778706 | TL7357H | 37 | 274 | 643 | 2 | AV REYES DE ESPAÑA 2 N2-4 SALAMANCA (SALAMANCA) | 23.18

## Geocoding a cadastral reference

The opposite query is also possible. When provided with a cadastral reference (`rc`), province (`province`) and municipality (`municipality`), the function `catr_ovc_get_cpmrc()` returns the coordinates (`lat` and `lon`) in a specified `srs`, along with the address (town, street and number).

    catr_ovc_get_cpmrc(
      rc = "13077A01800039",
      srs = "4230",
      province = "CIUDAD REAL",
      municipality = "SANTA CRUZ DE MUDELA"
    ) |>
      knitr::kable()

xcoord | ycoord | refcat | address | pc.pc1 | pc.pc2 | geo.xcen | geo.ycen | geo.srs | ldt
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
-3.456242 | 38.61966 | 13077A01800039 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL) | 13077A0 | 1800039 | -3.45624183836806 | 38.6196566583596 | EPSG:4230 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL)

The `province` and `municipality` arguments are optional, but if `municipality` is provided, `province` must also be provided. If a value is passed to the `province` argument while `municipality` is `NULL`, the function `catr_ovc_get_cpmrc()` displays a message and returns an empty tibble.

    catr_ovc_get_cpmrc(
      rc = "13077A01800039",
      municipality = "SANTA CRUZ DE MUDELA"
    ) |>
      knitr::kable()
    #> ✖ OVC service error 11: LA PROVINCIA ES OBLIGATORIA

refcat | geo.srs
--- | ---
13077A01800039 | EPSG:4326

When using only `rc`, the result is provided as expected:

    # Get the result without a warning.
    catr_ovc_get_cpmrc(rc = "13077A01800039") |>
      knitr::kable()

xcoord | ycoord | refcat | address | pc.pc1 | pc.pc2 | geo.xcen | geo.ycen | geo.srs | ldt
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
-3.457532 | 38.61843 | 13077A01800039 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL) | 13077A0 | 1800039 | -3.45753233627867 | 38.6184314024661 | EPSG:4326 | DS DISEMINADO Polígono 18 Parcela 39 000100200VH67C EL TIRADERO. SANTA CRUZ DE MUDELA (CIUDAD REAL)