...
| Code | Descrption |
|---|---|
<27700> | The SRID for the projection |
+title=British National Grid | The Title to display |
+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.999601 +x_0=400000 +y_0=-100000 +ellps=airy +units=m +no_defs no_defs | The Projection definition. In order to find the correct definition for your required projection please see http://spatialreference.org/ref/ select the relevant entry and then click on the Proj4 link which will give you what you require. |
| <> | The end of line |
Remember that your mapsources may be set up for WMS & WFS access. If your mapsources' associated .map files are set up to support multiple projections then make sure the epsg file referenced contains all the necessary projection definitions. Below is a typical epsg file shortened to only include projections typically used with British data.
| Code Block |
|---|
# WGS 84
<4326> +title=long/lat:WGS84 +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs no_defs <>
# ETRS89
<4258> +title=long/lat:ETRS89 +proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs no_defs <>
# OSGB 1936 / British National Grid
<27700> +title=British National Grid +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs <>
# TM75 / Irish Grid
<29903> +proj=tmerc +lat_0=53.5 +lon_0=-8 +k=1.000035 +x_0=200000 +y_0=250000 +a=6377340.189 +b=6356034.447938534 +units=m +no_defs no_defs <>
# OSNI 1952 / Irish National Grid
<29901> +proj=tmerc +lat_0=53.5 +lon_0=-8 +k=1.000000 +x_0=200000 +y_0=250000 +ellps=airy +units=m +no_defs no_defs <>
# IRENET95 / Irish Transverse Mercator
<2157> +proj=tmerc +lat_0=53.5 +lon_0=-8 +k=0.999820 +x_0=600000 +y_0=750000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs no_defs <>
# SR-ORG:6864
<3857> +proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs <>
# EPSG:3035
<3035> +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80 +units=m +no_defs <> |