Exercise: Measuring point coordinates using WMS Google maps
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# Specify the coordinate reference system (CRS) ETRS / UTM zone 32N. Search for the EPSG code: ''25832''. Three precise geodetic survey points are loaded into the viewer. The current active project CRS is displayed on the lower left frame of the viewer as EPSG:25832. | # Specify the coordinate reference system (CRS) ETRS / UTM zone 32N. Search for the EPSG code: ''25832''. Three precise geodetic survey points are loaded into the viewer. The current active project CRS is displayed on the lower left frame of the viewer as EPSG:25832. | ||
# Activate {{mitem|text=Web --> Openlayers plugin --> Google Maps --> Google Satellite}}. | # Activate {{mitem|text=Web --> Openlayers plugin --> Google Maps --> Google Satellite}}. | ||
| − | + | A high spatial resolution aerial othophoto originally aqcuired in 2009 provided by GeoBasis-DE/BKG (Bundesamt für KArtographie und Geodäsie, Frankfurt is loaded in the viewer. Note, the active CRS is autoamtically changed to EPSG:3857 which is WGS84/ Pseudo Mercator projection often used by web map services. | |
| + | # Add additional | ||
Revision as of 15:35, 30 June 2016
Coordinates are often needed for ground control points (GCP) with the objective to georeference remote sensing data or scanned maps without graticule. Google maps can be used as one source for registering point coordinates.
Import highly accurate DGPS points stored in a ASCII CSV file
- Click Add delimeted Text File. Select the input file GBdata\GBData\GNSS\Festpunkte_Forstbotanischer_Garten.csv. Define the X field: East and Y field North. OK.
- Specify the coordinate reference system (CRS) ETRS / UTM zone 32N. Search for the EPSG code: 25832. Three precise geodetic survey points are loaded into the viewer. The current active project CRS is displayed on the lower left frame of the viewer as EPSG:25832.
- Activate Web --> Openlayers plugin --> Google Maps --> Google Satellite.
A high spatial resolution aerial othophoto originally aqcuired in 2009 provided by GeoBasis-DE/BKG (Bundesamt für KArtographie und Geodäsie, Frankfurt is loaded in the viewer. Note, the active CRS is autoamtically changed to EPSG:3857 which is WGS84/ Pseudo Mercator projection often used by web map services.
- Add additional
