# WRF: EPSG code or spatial reference for Lambert conformal, Mercator and polar stereographic projections [closed]

I'm building an R package (https://github.com/ibarraespinosa/wrftools) to read namelist.wps and return a dynamic map which you can make zoom. In my case, it would be very beneficial because writing a namelist.wps can be tricky. The problem is that I need to know the EPSG or spatial reference (http://spatialreference.org/) to transform the spatial data to WGS84. Hence: What are the EPSG code for: Lambert conformal, Mercator and polar stereographic projections

Thanks

Edit 1: According to the WRF Manual , page 3-10: "As a general guideline,

1. the polar stereographic projection is best suited for high-latitude WRF domains,

2. the Lambert conformal projection is well suited for mid-latitude domains, and

3. the Mercator projection is good for low-latitude domains or domains with predominantly west-east extent."

What I want to do is to tell R how to recognize these projections (spatial references), so that I can plot into the map.

Note: The example is from Brazil but the idea is that it can be used anywhere.

I would like to know:

If projection is lambert, the EPSG code is XX or the spatial reference is "+proj=lcc +lat_1=YY..."

Thanks

• You will get a better result asking questions like this on GIS Stack Exchange. – Spencer Apr 19 '18 at 23:24
• I would like to caution you, however, that you're currently asking about projection algorithms, and a projection algorithm is only one part of a spatial reference's specification. So you're probably going to have to reformulate your question before you can get an answer. – Spencer Apr 19 '18 at 23:51
• @Spencer, yeah, perhaps, but these projections come from WRF model, so, I'm assuming that WRF model experts would know about this – Sergio Apr 20 '18 at 15:17
• WRF model looks like it takes a lot of custom spatial references. They're not going to be in EPSG. – mkennedy Apr 27 '18 at 1:30
• Dear @mkennedy, so, which are these custom spatial references? – Sergio Apr 27 '18 at 2:22

Spatial reference systems are coordinate systems that can be geographical coordinate systems defined on a model ellipsoid or projection coordinate systems.

A projection coordinate system is defined by four groups of parameters:

1. model ellipsoid,
2. projection type
3. projection parameters
4. measurement unit

EPSG codes refer to complete spatial reference systems or model ellipsoids.

You are saying that you want an EPSG code for projection coordinate systems that use WGS84 as model ellipsoids and Mercator, Lambert conformal conical, and stereographic projections. These projections require additional parameters such as the central meridian and origin latitude. Choice of parameters depends on your region of interest.

You could start with EPSG:4326 which is a geographical coordinate system with degrees as units.

Next, since your region of interest seems to be in the south of Brazil, consider EPSG:32722 that stays for Universal Transverse Mercator zone 22S and uses the WGS84 ellipsoid.

For a Lambert Conformal Conic projection consider ESRI:102015 that stays for South America Lambert Conformal Conic. This spatial reference uses a model ellipsoid that is different from WGS84, so this might be a problem for you. The standard parallel numbers for this projection are 5S and 42S meaning that the distortion would be greater for regions that lie away from these latitude, i.e. the Northern hemisphere or the Antarctic regions.

Finally for a Stereographic Polar you might consider EPSG:3031. An Antarctic Polar Stereographic projection coordinate system that uses WGS84 as a model ellipsoid.

• Dear @Dimitri Chubarov, thank you for your answer, but the example is from Brazil but the idea is that it can be used anywhere. What I want to do is to tell R what are the spatial references of my objects so that it can plot the domains into a map. – Sergio Apr 20 '18 at 15:28
• Note: 102015 is actually an Esri code, not an EPSG one. – mkennedy Apr 27 '18 at 1:18
• @mkennedy thank you for the correction. This seems to be also a mistake in QGIS srs.db. – Dmitri Chubarov Apr 27 '18 at 6:32
• @DmitriChubarov Yes, pretty much everyone says the authority for any well-known ID / code is EPSG, but their code range is 1 - 32766. – mkennedy Apr 27 '18 at 19:21