Does anybody have any suggestions for a projected coordinate system for the Northern part of South America? I have a data set that reaches from Venezuela to Southern Peru and I'd like to do some spatial autocorrelation on it. However, the current WGS84 is obviously a geographic coordinate system and not suitable for this type of analysis. I could just stick it in UTM 19 or 20 (north or south I guess given it spans the Equator) but I just wanted to know if anyone had any better suggestions.
You first need to decide what distortion properties would you like to control for. That is to say, are you interested in preserving area, distance or shape? There is a decision support tool for selecting projections that is quite user friendly and available for free from Oregon State University (Map Projection Selection Tool). Note that you can select the distortion property and a specific area of interest. The tool yields a recommended projection, a central meridian and PROJ.4 code.
You can use some projections that are provided by ESRI, depending on whether distance or area is important for you. They look very similar:
+proj=eqdc +lat_0=-32 +lon_0=-60 +lat_1=-5 +lat_2=-42 +x_0=0 +y_0=0 +ellps=aust_SA +units=m +no_defs
+proj=aea +lat_1=-5 +lat_2=-42 +lat_0=-32 +lon_0=-60 +x_0=0 +y_0=0 +ellps=aust_SA +units=m +no_defs
Both projections are included in newer GDAL and QGIS versions as EPSG:102032 and EPSG:102033
A third choice can be EPSG:2317 PSAD56 / ICN Regional using Lambert Conformal Conical:
+proj=lcc +lat_1=9 +lat_2=3 +lat_0=6 +lon_0=-66 +x_0=1000000 +y_0=1000000 +ellps=intl +towgs84=-288,175,-376,0,0,0,0 +units=m +no_defs