1 Getting started

1.1 Obtaining and saving API Key

CMAP hosts data on a Microsoft SQL Server. To retrieve data from the database, cmap4r requires an API key. For this, the user needs to register on the SimonsCMAP website and navigate to the "APIKeys" tab on the webpage to obtain an API key. The package allows the user to save the key as a keyring variable which will be used for data retrieval whenever required.

1.2 Installation and setup

First, open R in a command line or in an R console. In order to install the R package, first install the devtools R package using install.packages("devtools").

Next, install the cmap4r R package using devtools::install_github("simonscmap/cmap4r/cmap4r"). There are some other dependencies to install as well:

## Package for data processing:
install.packages("dplyr")  

## Packages for visualization:
install.packages("ggplot2")
install.packages("plotly")

Now, in your R session, run set_authorization() to set/reset the API Key. You will be prompted to enter the key on the command line or in a pop-up prompt. Alternatively, you can attempt to use any of the functions (e.g. get_catalog()) and you will be prompted to enter the key.

1.3 Catalog of data

You can obtain the latest version of the data catalog for the CMAP data (https://cmap.readthedocs.io/en/latest/catalog/catalog.html) to R using get_catalog(), partially reproduced here.

get_catalog() %>%
  select(Variable, Table_Name, Unit, Sensor, Unit) %>%
  head(20) %>%
  kable()

Variable	Table_Name	Unit	Sensor
vgosa	tblAltimetry_REP	m/s	Satellite
vgos	tblAltimetry_REP	m/s	Satellite
sla	tblAltimetry_REP	m	Satellite
adt	tblAltimetry_REP	m	Satellite
ugosa	tblAltimetry_REP	m/s	Satellite
ugos	tblAltimetry_REP	m/s	Satellite
wind_speed_rms	tblWind_NRT	m/s	Satellite
eastward_wind_rms	tblWind_NRT	m/s	Satellite
wind_stress	tblWind_NRT	Pa	Satellite
eastward_wind	tblWind_NRT	m/s	Satellite
surface_downward_eastward_stress	tblWind_NRT	Pa	Satellite
wind_speed	tblWind_NRT	m/s	Satellite
surface_downward_northward_stress	tblWind_NRT	Pa	Satellite
northward_wind	tblWind_NRT	m/s	Satellite
northward_wind_rms	tblWind_NRT	m/s	Satellite
sst	tblSST_AVHRR_OI_NRT	C	Satellite
ftle_bw_sla	tblLCS_REP	1/day	Satellite
disp_bw_sla	tblLCS_REP	deg	Satellite
ftle_fw_sla	tblLCS_REP	1/day	Satellite
disp_fw_sla	tblLCS_REP	deg	Satellite