ArcGIS Interface¶

This interface layer provides a lightweight interface to the underlying PostGIS data stored in Tablo similar to that provided by an ArcGIS feature service. The services stored in Tablo can be accessed using endpoints such as {tablo_server}/rest/services/{service_id}/FeatureServer, where tablo_server is the host name of the server and service_id is the ID of the service within Tablo.

Accessing the FeatureServer endpoint will provide data about the Feature Service itself, such as version and layer information. Since these represent feature services, they are limited to a single layer, so the {tablo_server}/rest/services/{service_id}/FeatureServer/0 endpoint will give more information about the specific layer properties, such as attributes, extent and related tables (if they exist).

This is the main interface layer that most external applications will use to access and query the spatial data stored within Tablo. The access points here are open and not restricted by any authentication layers, so authentication would need to happen outside of Tablo.

The Feature Server Layer will have more information provided by the layer specific endpoints.

Query¶

class tablo.interfaces.arcgis.views.QueryView(*args, **kwargs)¶

Query is the main way data is retrieved from a feature service. This implements an api similar to ArcGIS http://resources.arcgis.com/en/help/rest/apiref/fsquery.html, but limited to the following parameters listed below. It can be accessed using the endpoint at {tablo_server}/rest/services/{service_id}/FeatureServer/0/query.

Keyword arguments can be passed as query arguments such as {tablo_server}/rest/services/{service_id}/FeatureServer/0/query?f=json&offset=2&returnIdsOnly=true

Keyword Arguments:

geometryType

(string) The type of geometry sent in the geometry argument. Valid values are esriGeometryEnvelope and esriGeometryPolygon
limit

(int) The maximum number of features returned by the query
objectIds

(comma-separated list) A comma-separated list of ObjectIDs for the features in the table that you want to query
offset

(int) The starting record number for the query, often used in concert with the limit to paginate groups of responses
orderByFields

(string List) The names of the attributes to order the response by. Optional ASC and DESC flags can be used here to specify ascending or descending order. The default order is ASC.
outFields

(string List) The names of the attributes to include in the response
outSR

(spatial reference) The spatial reference for the returned geometry.
returnCountOnly

(boolean) Returns only the count of the matching features
returnGeometry

(boolean) Whether or not to return the geometry of the feature in the query response.
returnIdsOnly

(boolean) Returns only the ObjectIDs of the matching features
time

([float, float]) The start_time and end_time for the query (in seconds since the epoch)
where

(string) A where clause for the query

Returns:

A JSON response, with slightly different syntax depending on the information requested with the keyword arguments. Example responses can be seen at http://resources.arcgis.com/en/help/rest/apiref/fsquery.html

TimeQuery¶

class tablo.interfaces.arcgis.views.TimeQueryView(*args, **kwargs)¶

TimeQuery is a way to get back consolidated time data about a time-enabled feature service in Tablo. It is an extension to the base ArcGIS interface, but is built on top of it. It can be accessed at the {tablo_server}/rest/services/{service_id}/FeatureServer/0/query endpoint. It does not take any keyword arguments but returns a list of features that specify the location and count of feature occurrences over the full time of the feature service’s time extent.

Response:

A JSON object similar to the following:

{
    "fields":[
        {
            "type":"esriFieldTypeInteger",
            "name":"count",
            "alias":"count"
        }
    ],
    "geometryType":"esriGeometryPoint",
    "count":3,
    "features":[
        {
            "attributes":{
                "count":90
            },
            "geometry":{
                "y":4020267.35731412,
                "x":-12974132.1182389
            }
        },
        {
            "attributes":{
                "count":173
            },
            "geometry":{
                "y":4021352.9816459,
                "x":-12978661.118326
            }
        },
        {
            "attributes":{
                "count":1572
            },
            "geometry":{
                "y":4020153.56924836,
                "x":-12978123.2336784
            }
        }
    ]
}

GenerateRenderer¶

class tablo.interfaces.arcgis.views.GenerateRendererView(*args, **kwargs)¶

GenerateRenderer operation groups data using the supplied classificationDef to create a renderer object. This renderer object can then be used as a style or to create a legend. It can be accessed using the endpoint at {tablo_server}/rest/services/{service_id}/FeatureServer/0/generateRenderer.

Keyword Arguments:

classificationDef

A classificationDef object with a JSON syntax like:

{
    "type": "classBreaksDef",
    "classificationField": "POP2010",
    "classificationMethod": "esriClassifyNaturalBreaks",
    "breakCount": 5,
    "normalizationType": "esriNormalizeByField",
    "normalizationField": "Area"
}

Returns:

An ArcGIS renderer JSON object, like this:

{
    "type": "simple",
    "symbol":
    {
        "type": "esriSMS",
        "style": "esriSMSCircle",
        "color": [255,0,0,255],
        "size": 5,
        "angle": 0,
        "xoffset": 0,
        "yoffset": 0,
        "outline":
        {
         "color": [0,0,0,255],
         "width": 1
        }
    },
    "label": "",
    "description": ""
}