Update documentation

Also old GDS links were replaced with those of the Open Data portal

conversion.go

@@ -21,7 +21,7 @@ type ZR struct {
 
 // Common Z-R relationships
 var (
-	Aniol80          = NewZR(256, 1.42) // operational use in germany, described in [6]
+	Aniol80          = NewZR(256, 1.42) // operational use in germany, described in [5]
 	Doelling98       = NewZR(316, 1.50) // operational use in switzerland
 	JossWaldvogel70  = NewZR(300, 1.50)
 	MarshallPalmer55 = NewZR(200, 1.60) // operational use in austria

radolan.go

 // Package radolan parses the DWD RADOLAN / RADVOR radar composite format. This data
-// is available at the Global Basic Dataset (http://www.dwd.de/DE/leistungen/gds/gds.html).
+// is available at the Open Data Portal (https://www.dwd.de/DE/leistungen/opendata/opendata.html).
 // The obtained results can be processed and visualized with additional functions.
 //
-// Currently the national grid [1][4] and the extended european grid [5] are supported.
-// Tested input products are PG, FZ, SF, RW, RX and EX. Those can be considered working with
-// sufficient accuracy.
+// Tested input products and grids:
+//
+//	| Product | Grid              | Description             |
+//	| ------- | ----------------- | ----------------------- |
+//	| EX      | middle-european   | reflectivity            |
+//	| FX      | national          | nowcast reflectivity    |
+//	| FZ      | national          | nowcast reflectivity    |
+//	| PE      | local             | echo top                |
+//	| PF      | local             | reflectivity            |
+//	| PG      | national picture  | reflectivity            |
+//	| PR      | local             | doppler radial velocity |
+//	| PX      | local             | reflectivity            |
+//	| PZ      | local             | 3D reflectivity CAPPI   |
+//	| RW      | national          | hourly accumulated      |
+//	| RX      | national          | reflectivity            |
+//	| SF      | national          | daily accumulated       |
+//	| WX      | extended national | reflectivity            |
+//
+// Those can be considered working with sufficient accuracy.
 //
 // In cases, where the publicly available format specification is unprecise or contradictory,
 // reverse engineering was used to obtain reasonable approaches.
@@ -12,10 +28,10 @@
 //
 //	[1] https://www.dwd.de/DE/leistungen/radolan/radolan_info/radolan_radvor_op_komposit_format_pdf.pdf
 //	[2] https://www.dwd.de/DE/leistungen/gds/weiterfuehrende_informationen.zip
-//	[3]  - legend_radar_products_fz_forecast.pdf
-//	[4]  - legend_radar_products_pg_coordinates.pdf
-//	[5]  - legend_radar_products_radolan_rw_sf.pdf
-//	[6] https://www.dwd.de/DE/leistungen/radarniederschlag/rn_info/download_niederschlagsbestimmung.pdf
+//	[3] https://www.dwd.de/DE/leistungen/radarprodukte/formatbeschreibung_fxdaten.pdf
+//	[4] https://www.dwd.de/DE/leistungen/opendata/help/radar/radar_pg_coordinates_pdf.pdf
+//	[5] https://www.dwd.de/DE/leistungen/radarniederschlag/rn_info/download_niederschlagsbestimmung.pdf
+//	[6] hex editor and much reverse engineering
 package radolan
 
 import (

translate.go

@@ -62,7 +62,7 @@ func (c *Composite) detectGrid() grid {
 
 // cornerPoints returns corner coordinates of the national, extended or
 // middle-european grid based on the dimensions of the composite. The used
-// values are described in [1], [4] and [5].  If an error is returned,
+// values are described in [1], [4].  If an error is returned,
 // translation methods will not work.
 func (c *Composite) cornerPoints() (originTop, originLeft, edgeBottom, edgeRight float64, err error) {
 	switch c.detectGrid() {
@@ -72,10 +72,10 @@ func (c *Composite) cornerPoints() (originTop, originLeft, edgeBottom, edgeRight
 	case nationalPictureGrid: // (pg) described in [4]
 		originTop, originLeft = 54.66218275, 1.900684377 // N, E
 		edgeBottom, edgeRight = 46.98044293, 14.73300934 // N, E
-	case extendedNationalGrid: // described in [5]
+	case extendedNationalGrid: // described in [1]
 		originTop, originLeft = 55.5482, 03.0889 // N, E
 		edgeBottom, edgeRight = 46.1827, 15.4801 // N, E
-	case middleEuropeanGrid: // described in [5]
+	case middleEuropeanGrid: // described in [1]
 		originTop, originLeft = 56.5423, -0.8654 // N, E
 		edgeBottom, edgeRight = 43.8736, 18.2536 // N, E
 	default: