2 replies to this topic

[chris henrick]

Hello,

Maybe some savy QGIS users out there could assist me with a simple question relating to projecting map data in QGIS.

I'm making a map of Ontario, Canada and would like to create a custom CRS for the province using Natural Earth 10m vector data. I've seen that a CRS resource does exist at the following website: http://spatialreference.org/ but it appears the website is currently not working.

So, I've modified an existing CRS from this tutorial: http://www.baruch.cu...gis_prac_4.html to try to center the projection on Ontario.

Here is my CRS code, for an Lambert Conformal Conic projection: +proj=lcc +lat_1=40 +lat_2=80 +lat_060 +lon_0=-90 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs.

Also, I'm going to be bringing the map into AI to apply styles. I do not have Mapublisher so will export the map from QGIS as an SVG.

Anyone have any comments or advice? I'd appreciate it.

much thanks,

-Chris

[Melita Kennedy]

...

I'm making a map of Ontario, Canada and would like to create a custom CRS for the province using Natural Earth 10m vector data. I've seen that a CRS resource does exist at the following website: http://spatialreference.org/ but it appears the website is currently not working.

So, I've modified an existing CRS from this tutorial: http://www.baruch.cu...gis_prac_4.html to try to center the projection on Ontario.

Here is my CRS code, for an Lambert Conformal Conic projection: +proj=lcc +lat_1=40 +lat_2=80 +lat_060 +lon_0=-90 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs.

...

The standard parallel 2 (lat_2) value seems too far north. Ontario Ministry of Natural Resources has a Lambert conformal conic-based coordinate system that uses:

central meridian: -85.0
1st std parallel: 44.5
2nd std parallel: 53.5
lat of origin: 0.0

false easting: 930000.0 m
false northing: 6430000.0 m (this one I don't understand. I think either this value or the lat of origin value is incorrect as the Y values currently are probably around 12 million m. You could leave these set to zeroes).

It may be a transcription error, but note the +lat_060 option in the proj command.

Melita

[chris henrick]

...

I'm making a map of Ontario, Canada and would like to create a custom CRS for the province using Natural Earth 10m vector data. I've seen that a CRS resource does exist at the following website: http://spatialreference.org/ but it appears the website is currently not working.

So, I've modified an existing CRS from this tutorial: http://www.baruch.cu...gis_prac_4.html to try to center the projection on Ontario.

Here is my CRS code, for an Lambert Conformal Conic projection: +proj=lcc +lat_1=40 +lat_2=80 +lat_060 +lon_0=-90 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs.

...

The standard parallel 2 (lat_2) value seems too far north. Ontario Ministry of Natural Resources has a Lambert conformal conic-based coordinate system that uses:

central meridian: -85.0
1st std parallel: 44.5
2nd std parallel: 53.5
lat of origin: 0.0

false easting: 930000.0 m
false northing: 6430000.0 m (this one I don't understand. I think either this value or the lat of origin value is incorrect as the Y values currently are probably around 12 million m. You could leave these set to zeroes).

It may be a transcription error, but note the +lat_060 option in the proj command.

Melita

Ah, thanks Melita. Those coordinates sound much more accurate and definitely help the map's look. Also, I didn't notice the syntax error. Thanks, I appreciate your help.

-Chris