austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5
Icon for Socrata external plugin

Query the Data Delivery Network

Query the DDN

The 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 procotol. 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 vision_zero_crash_report_data table in this repository, by referencing it like:

"austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5:latest"."vision_zero_crash_report_data"

or in a full query, like:

SELECT 
    ":id", -- Socrata column ID
    ":@computed_region_m2th_e4b7",
    ":@computed_region_rxpj_nzrk",
    "motorcycle_serious_injury_count",
    "pedestrian_serious_injury_count",
    "onsys_fl", -- Flag indicates whether primary road of crash was on the TxDOT highway system.
    "bicycle_serious_injury_count",
    "bicycle_death_count",
    "pedestrian_death_count",
    "road_constr_zone_fl", -- Construction Zone - Indicates whether the crash occurred in or was related to a construction, maintenance, or utility work zone, regardless of whether or not workers were actually present at the time of the crash
    "motorcycle_fl", -- Motorcycle involved crash flag
    "apd_confirmed_fatality", -- APD Fatality flag
    "contrib_factr_p2_id", -- The second factor for a given vehicle which the officer felt possibly contributed to the crash
    "units_involved", -- Mode of units involved in crash
    "sus_serious_injry_cnt", -- Total Suspected Serious Injury Count
    "rpt_block_num", -- Reported Block Number (road on which crash occurred)
    "rpt_street_name", -- Reported Street Name (road on which crash occurred)
    "longitude", -- Derived Longitude map coordinate of the crash
    "atd_mode_category_metadata", -- Description of units involved in crash
    "crash_speed_limit", -- Speed Limit
    "street_nbr", -- Derived Street Number - Block number of primary street where crash occurred as determined by the Locator application
    "motor_vehicle_fl", -- Motor vehicle involved crash flag
    "point", -- Point datatype created with crash latitude and longitude to enable request of GeoJSON.
    "case_id", -- Case ID
    "street_name_2", -- Derived Street Name 2 - The road name for the secondary road related to the crash location (If applicable)
    "crash_date", -- Crash Date
    "motor_vehicle_death_count",
    "tot_injry_cnt", -- Total Injury Count
    "unkn_injry_cnt", -- Total Unknown Injury Count
    "rpt_latitude", -- Reported Latitude 
    "motorcycle_death_count",
    "poss_injry_cnt", -- Total Possible Injury Count
    "rpt_longitude", -- Reported Longitude
    "crash_id", -- TxDOT C.R.I.S. system-generated unique identifying number for a crash
    "pedestrian_fl", -- Pedestrian involved crash flag
    "contrib_factr_p1_id", -- The first factor for a given vehicle which the officer felt possibly contributed to the crash
    "death_cnt", -- Total Death Count
    "street_nbr_2", -- Derived Street Number 2 - Block number of secondary street related to the crash location as determined by the Locator application  (If applicable)
    "private_dr_fl", -- Flag indicating whether crash occurred on a private drive or road/private property/parking lot.
    "other_serious_injury_count",
    "other_death_count",
    "motor_vehicle_serious_injury_count",
    "other_fl", -- Other involved crash flag
    "bicycle_fl", -- Bicyclist involved crash flag
    "non_injry_cnt", -- Total Not Injured Count
    "nonincap_injry_cnt", -- Total Non-incapacitating Injury Count
    "crash_sev_id", -- Crash Severity - Most severe injury suffered by any one person involved in the crash ( 0=UNKNOWN, 1=INCAPACITATING INJURY, 2=NON-INCAPACITATING INJURY, 3=POSSIBLE INJURY, 4=KILLED, 5=NOT INJURED)
    "street_name", -- Derived Street Name - Name of the road crash occurred on, as determined by the Locator application.
    "latitude", -- Derived Latitude map coordinate of the crash
    "rpt_street_sfx", -- Reported Street Suffix (road on which crash occurred)
    "rpt_street_pfx", -- Reported Street Prefix (road on which crash occurred)
    "crash_fatal_fl", -- Fatal Crash Identifier - Indicates that the crash involved one or more fatalities
    "crash_time", -- Crash Time - Time crash occurred
    "apd_confirmed_death_count", -- APD Fatality Count
    ":@computed_region_8spj_utxs",
    ":@computed_region_jcrc_4uuy",
    ":@computed_region_q9nd_rr82",
    ":@computed_region_e9j2_6w3z"
FROM
    "austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5:latest"."vision_zero_crash_report_data"
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 austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5 with SQL in under 60 seconds.

This repository is an "external" repository. That means it's hosted elsewhere, in this case at data.austintexas.gov. When you queryaustintexas-gov/vision-zero-crash-report-data-y2wy-tgr5: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

Install Splitgraph Locally
bash -c "$(curl -sL https://github.com/splitgraph/splitgraph/releases/latest/download/install.sh)"
 

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.austintexas.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 \
  "austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5" \
  --handler-options '{
    "domain": "data.austintexas.gov",
    "tables": {
        "vision_zero_crash_report_data": "y2wy-tgr5"
    }
}'

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, austintexas-gov/vision-zero-crash-report-data-y2wy-tgr5 is just another Postgres schema.

Related Documentation: