Query the Data Delivery Network
Query the DDNThe easiest way to query any data on Splitgraph is via the "Data Delivery Network" (DDN). The DDN is a single endpoint that speaks the PostgreSQL wire protocol. Any Splitgraph user can connect to it at data.splitgraph.com:5432 and query any version of over 40,000 datasets that are hosted or proxied by Splitgraph.
For example, you can query the citizen_statewide_lake_monitoring_assessment table in this repository, by referencing it like:
"ny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht:latest"."citizen_statewide_lake_monitoring_assessment"or in a full query, like:
SELECT
":id", -- Socrata column ID
"dec_region", -- NYSDEC Region where facility is located: Region 1: (Long Island) Nassau and Suffolk counties; Region 2: (New York City) Brooklyn, Bronx, Manhattan, Queens and Staten Island; Region 3: (Lower Hudson Valley) Dutchess, Orange, Putnam, Rockland, Sullivan, Ulster and Westchester counties; Region 4: (Capital Region/Northern Catskills) Albany, Columbia, Delaware, Greene, Montgomery, Otsego, Rensselaer, Schenectady and Schoharie counties; Region 5: (Eastern Adirondacks/Lake Champlain) Clinton, Essex, Franklin, Fulton, Hamilton, Saratoga, Warren and Washington counties; Region 6: (Western Adirondacks/Eastern Lake Ontario) Herkimer, Jefferson, Lewis, Oneida and St. Lawrence counties; Region 7: (Central New York) Broome, Cayuga, Chenango, Cortland, Madison, Onondaga, Oswego, Tioga and Tompkins counties; Region 8: (Western Finger Lakes) Chemung, Genesee, Livingston, Monroe, Ontario, Orleans, Schuyler, Seneca, Steuben, Wayne and Yates counties; Region 9: (Western New York) Allegany, Chautauqua, Cattaraugus, Erie, Niagara and Wyoming counties.
"lake_name", -- Name of lake
"area_hectares", -- Area in hectares
"access_yes_no", -- Indicates if public access is available on lake
"water_quality_classification", -- The lakes designated best usage classification. A,AA, AASpec = Drinking water supply; B = Public Bathing; C = Recreation; (T) trout survival; (TS) trout propagation.
"georeference", -- Open Data/Socrata-generated geocoding information from supplied address components.
"cslap_number", -- A unique number used to identify each program lake
"waterbody_index_number", -- A unique string used to identify the lake within New York State Regulations
"bathymetric_map_available_yes_no", -- Indicates if a bathymetric map is available for the lake
"last_year_sampled", -- The last year in which the lake was sampled by CSLAP volunteers
"area_acres", -- The area of lake in acres
"town", -- The town in which the sampling location on the lake is in.
"depth_feet", -- Mean lake depth in feet
"sampling_years", -- Years that the lake was sampled by CSLAP volunteers
"trophic_state", -- A ranking of nutrient enrichment status of a lake where: oligotrophic = nutrient poor and low productivity; mesotrophic = moderately productive; and eutrophic = very productive and fertile; mesoligotrophic = between oligotrophic and mesotrophic; mesoeutrophic = between mesotrophic and eutrophic
"longitude", -- Longitude in decimal degrees
"number_of_years_sampled", -- Number of years the lake has been sampled by CSLAP volunteers
"priority_waterbody_list_number", -- Priority waterbody listing identification number. Blanks indicate lakes without an assigned priority waterbody list number.
"public_private_access", -- Description of the access type to the lake
"mean_depth_meters", -- Mean lake depth in meters
"watershed_name", -- The major drainage basin within which the lake is located.
"elevation_meters", -- Elevation in meters above sea level
"county", -- The county in which the sampling location on the lake is in.
"watershed_area_hectares", -- Lake watershed area in hectares
"public_access", -- Description of public access to the lake
"latitude" -- Latitude in decimal degrees
FROM
"ny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht:latest"."citizen_statewide_lake_monitoring_assessment"
LIMIT 100;Connecting to the DDN is easy. All you need is an existing SQL client that can connect to Postgres. As long as you have a SQL client ready, you'll be able to query ny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht with SQL in under 60 seconds.
This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.ny.gov. When you queryny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht:latest on the DDN, we "mount" the repository using the socrata mount handler. The mount handler proxies your SQL query to the upstream data source, translating it from SQL to the relevant language (in this case SoQL).
We also cache query responses on the DDN, but we run the DDN on multiple nodes so a CACHE_HIT is only guaranteed for subsequent queries that land on the same node.
Query Your Local Engine
bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"Read the installation docs.
Splitgraph Cloud is built around Splitgraph Core (GitHub), which includes a local Splitgraph Engine packaged as a Docker image. Splitgraph Cloud is basically a scaled-up version of that local Engine. When you query the Data Delivery Network or the REST API, we mount the relevant datasets in an Engine on our servers and execute your query on it.
It's possible to run this engine locally. You'll need a Mac, Windows or Linux system to install sgr, and a Docker installation to run the engine. You don't need to know how to actually use Docker; sgrcan manage the image, container and volume for you.
There are a few ways to ingest data into the local engine.
For external repositories (like this repository), the Splitgraph Engine can "mount" upstream data sources by using sgr mount. This feature is built around Postgres Foreign Data Wrappers (FDW). You can write custom "mount handlers" for any upstream data source. For an example, we blogged about making a custom mount handler for HackerNews stories.
For hosted datasets, where the author has pushed Splitgraph Images to the repository, you can "clone" and/or "checkout" the data using sgr cloneand sgr checkout.
Mounting Data
This repository is an external repository. It's not hosted by Splitgraph. It is hosted by data.ny.gov, and Splitgraph indexes it. This means it is not an actual Splitgraph image, so you cannot use sgr clone to get the data. Instead, you can use the socrata adapter with the sgr mount command. Then, if you want, you can import the data and turn it into a Splitgraph image that others can clone.
First, install Splitgraph if you haven't already.
Mount the table with sgr mount
sgr mount socrata \
"ny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht" \
--handler-options '{
"domain": "data.ny.gov",
"tables": {
"citizen_statewide_lake_monitoring_assessment": "b6x3-58ht"
}
}'That's it! Now you can query the data in the mounted table like any other Postgres table.
Query the data with your existing tools
Once you've loaded the data into your local Splitgraph engine, you can query it with any of your existing tools. As far as they're concerned, ny-gov/citizen-statewide-lake-monitoring-assessment-b6x3-58ht is just another Postgres schema.