WKT-PARSER-DART

Wkt-parser-dart is the Dart version of proj4js/wkt-parser to convert a WKT CRS string into a Map<String, dynamic> object.

Installing

Add wkt_parser to pubspec.yml (dependencies section), then run pub get to download the new dependencies.

dependencies:
                  wkt_parser: any # or the latest version on Pub
                

Using

You can convert any OGC WKT / ESRI WKT definition string copied from epsg.io into a Map<String,dynamic> format which then can be further converted into JSON to be fully interoperable with any programming languages. This example uses the OGC WKT of EPSG:23700.

import 'package:wkt_parser/wkt_parser.dart' as wkt_parser;
                
                void main() {
                  // WKT CRS string
                  var wktText =
                      'PROJCS["HD72 / EOV",GEOGCS["HD72",DATUM["Hungarian_Datum_1972",SPHEROID["GRS 1967",6378160,298.247167427,AUTHORITY["EPSG","7036"]],TOWGS84[52.17,-71.82,-14.9,0,0,0,0],AUTHORITY["EPSG","6237"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4237"]],PROJECTION["Hotine_Oblique_Mercator_Azimuth_Center"],PARAMETER["latitude_of_center",47.14439372222222],PARAMETER["longitude_of_center",19.04857177777778],PARAMETER["azimuth",90],PARAMETER["rectified_grid_angle",90],PARAMETER["scale_factor",0.99993],PARAMETER["false_easting",650000],PARAMETER["false_northing",200000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Y",EAST],AXIS["X",NORTH],AUTHORITY["EPSG","23700"]]';
                  // Parsed object of type ProjWKT
                  var output = wkt_parser.parseWKT(wktText);
                  // This returns a JSON encoded string of the WKT
                  print(output.toString());
                }
                

The result should be (with JSON encode):

{
                  "type": "PROJCS",
                  "name": "HD72 / EOV",
                  "GEOGCS": {
                    "name": "HD72",
                    "DATUM": {
                      "name": "Hungarian_Datum_1972",
                      "SPHEROID": {
                        "name": "GRS 1967",
                        "a": 6378160.0,
                        "rf": 298.247167427,
                        "AUTHORITY": {
                          "EPSG": "7036"
                        }
                      },
                      "TOWGS84": [52.17, -71.82, -14.9, 0.0, 0.0, 0.0, 0.0],
                      "AUTHORITY": {
                        "EPSG": "6237"
                      }
                    },
                    "PRIMEM": {
                      "name": "greenwich",
                      "convert": 0.0,
                      "AUTHORITY": {
                        "EPSG": "8901"
                      }
                    },
                    "UNIT": {
                      "name": "degree",
                      "convert": 0.0174532925199433,
                      "AUTHORITY": {
                        "EPSG": "9122"
                      }
                    },
                    "AUTHORITY": {
                      "EPSG": "4237"
                    }
                  },
                  "PROJECTION": "Hotine_Oblique_Mercator_Azimuth_Center",
                  "latitude_of_center": 47.14439372222222,
                  "longitude_of_center": 19.04857177777778,
                  "azimuth": 90.0,
                  "rectified_grid_angle": 90.0,
                  "scale_factor": 0.99993,
                  "false_easting": 650000.0,
                  "false_northing": 200000.0,
                  "UNIT": {
                    "name": "metre",
                    "convert": 1.0,
                    "AUTHORITY": {
                      "EPSG": "9001"
                    }
                  },
                  "AXIS": [
                    ["Y", "EAST"],
                    ["X", "NORTH"]
                  ],
                  "AUTHORITY": {
                    "EPSG": "23700"
                  },
                  "projName": "Hotine_Oblique_Mercator_Azimuth_Center",
                  "units": "meter",
                  "to_meter": 1.0,
                  "datumCode": "hungarian_datum_1972",
                  "ellps": "GRS 1967",
                  "a": 6378160.0,
                  "rf": 298.247167427,
                  "datum_params": [52.17, -71.82, -14.9, 0.0, 0.0, 0.0, 0.0],
                  "k0": 0.99993,
                  "lat0": 0.8228248943093227,
                  "longc": 0.3324602953246919,
                  "x0": 650000.0,
                  "y0": 200000.0,
                  "alpha": 1.5707963267948966,
                  "srsCode": "HD72 / EOV"
                }
                

Author

Wkt-parser-dart was ported from proj4js/wkt-parser by Gergely Padányi-Gulyás (@fegyi001) at Ulyssys Ltd, Budapest, Hungary.

Changelog

2.0.0 - 2021-03-23

• Stable null safety release
• BREAKING CHANGE: parseWKT now returns Map<String, dynamic> instead of Map<dynamic, dynamic>

1.0.7 - 2020-03-20

• Merge fix

1.0.6 - 2020-03-20

• Rename example file for dart pub to find it

1.0.5 - 2020-03-20

• Rename example file for dart pub to find it
• Longer description for dart pub

1.0.4 - 2020-03-20

• Fix in cleanWKT

1.0.3 - 2020-03-04

• Add missing params to ProjWKT

1.0.2 - 2020-03-04

• Rename WKT to ProjWKT
• Rename parse() to parseWKT()

1.0.1 - 2020-03-03

• Class WKT with static parse() method
• Getters for WKT object parameters

1.0.0 - 2020-03-02

• Initial version
• It produces the same result as proj4js/wkt-parser for all the tests defined in proj4js/wkt-parser