hana

README

HANA MVT Provider

The HANA MVT provider manages querying for tile requests against a HANA database with Vector Tiles support to handle the MVT encoding at the database.

The connection between tegola and HANA is configured in a tegola.toml file. An example minimum connection config:

[[providers]]
name = "test_hana"       # provider name is referenced from map layers (required)
type = "mvt_hana"        # the type of data provider must be "mvt_hana" for this data provider (required)
uri = "hdb://myuser:mypassword@something.hanacloud.ondemand.com:443?" # HANA connection string (required)

Connection Properties

• uri (string): [Required] HANA connection string
• name (string): [Required] provider name is referenced from map layers
• type (string): [Required] the type of data provider. must be "hana" to use this data provider
• srid (int): [Optional] The default SRID for the provider. Defaults to WebMercator (3857) but also supports WGS84 (4326)

Connection string properties

Example

# {protocol}://{user}:{password}@{host}:{port}/{database}?{options}=
hdb://myuser:mypassword@something.hanacloud.ondemand.com:443?TLSInsecureSkipVerify&timeout=3600&max_connections=30

Options

• timeout: [Optional] Driver side connection timeout in seconds.
• TLSRootCAFile [Optional] Path,- filename to root certificate(s).
• TLSServerName [Optional] ServerName to verify the hostname. By setting TLSServerName=host, the provider will set TLSServerName same as 'host' value in uri.
• TLSInsecureSkipVerify [Optional] Controls whether a client verifies the server's certificate chain and host name.
• max_connections: [Optional] The max connections to maintain in the connection pool. Defaults to 100. 0 means no max.
• max_connection_idle_time: [Optional] The maximum time an idle connection is kept alive. Defaults to "30m".
• max_connection_life_time [Optional] The maximum time a connection lives before it is terminated and recreated. Defaults to "1h".

Provider Layers

In addition to the connection configuration above, Provider Layers need to be configured. A Provider Layer tells tegola how to query HANA for a certain layer. When using the HANA MVT Provider the ST_AsMVTGeom() MUST be used. An example minimum config using the sql config option:

[[providers.layers]]
name = "landuse"
# MVT data provider can use both table names and SQL statements. Internally, the provider wraps an SQL query by using 
# ST_AsMVT and ST_AsMVTGeom functions.
tablename = "gis.zoning_base_3857"

Provider Layers Properties

• name (string): [Required] the name of the layer. This is used to reference this layer from map layers.
• geometry_fieldname (string): [Optional] the name of the filed which contains the geometry for the feature. Defaults to geom.
• id_fieldname (string): [Optional] the name of the feature id field. defaults to gid.
• geometry_type (string): [Optional] the layer geometry type. If not set, the table will be inspected at startup to try and infer the gemetry type. Valid values are: Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, GeometryCollection.
• srid (int): [Optional] the SRID of the layer. Supports 3857 (WebMercator) only.
• sql (string): [Required] custom SQL to use use. Supports the following tokens:
  • !BBOX! - [Required] will be replaced with the bounding box of the tile before the query is sent to the database. !bbox! and!BOX! are supported as well for compatibilitiy with queries from Mapnik and MapServer styles.
  • !X! - [Optional] will replaced with the "X" value of the requested tile.
  • !Y! - [Optional] will replaced with the "Y" value of the requested tile.
  • !Z! - [Optional] will replaced with the "Z" value of the requested tile.
  • !ZOOM! - [Optional] will be replaced with the "Z" (zoom) value of the requested tile.
  • !SCALE_DENOMINATOR! - [Optional] scale denominator, assuming 90.7 DPI (i.e. 0.28mm pixel size)
  • !PIXEL_WIDTH! - [Optional] the pixel width in meters, assuming 256x256 tiles
  • !PIXEL_HEIGHT! - [Optional] the pixel height in meters, assuming 256x256 tiles
  • !ID_FIELD! - [Optional] the id field name
  • !GEOM_FIELD! - [Optional] the geom field name
  • !GEOM_TYPE! - [Optional] the geom type if defined otherwise ""
• buffer (int): [Optional] the buffer distance by which the clipped geometry may exceed the tile's area. Defaults to 256.
• clip_geometry (bool): [Optional] the flag to control whether the geometry is clipped to the tile bounds or not. Defaults to TRUE.

Example mvt_hana and map config

[[providers]]
name = "test_hana"
type = "mvt_hana"
uri = "hdb://myuser:mypassword@something.hanacloud.ondemand.com:443?" # HANA connection string (required)
srid = 3857                                                           # The only supported srid is 3857 (optional)

  [[providers.layers]]
  name = "landuse"
  sql = "SELECT geom, gid FROM gis.landuse WHERE !BBOX!"

[[maps]]
name = "cities"
center = [-90.2,38.6,3.0]  # where to center of the map (lon, lat, zoom)

  [[maps.layers]]
  name = "landuse"
  provider_layer = "test_hana.landuse"
  min_zoom = 0
  max_zoom = 14

Example mvt_hana and map config for SRID 4326

When using a 4326 projection with ST_AsMVT the SQL statement needs to be modified. ST_AsMVTGeom is expecting data in 3857 projection so the geometries and the !BBOX! token need to be transformed prior to ST_AsMVTGeom processing them. For example:

[[providers]]
name = "test_hana"
type = "mvt_hana"
uri = "hdb://myuser:mypassword@something.hanacloud.ondemand.com:443?" # HANA connection string (required)
srid = 3857                                                           # The only supported srid is 3857 (optional)

  [[providers.layers]]
  name = "landuse"
  sql = "SELECT * FROM (SELECT id, name, geom.ST_Transform(3857) AS geom FROM ne_50m_rivers_lake_centerlines) AS sub WHERE !BBOX!"

[[maps]]
name = "cities"
center = [-90.2,38.6,3.0]  # where to center of the map (lon, lat, zoom)

  [[maps.layers]]
  name = "landuse"
  provider_layer = "test_hana.landuse"
  min_zoom = 0
  max_zoom = 14

Testing

Testing is designed to work against a live SAP HANA database. To see how to set up a database check this github actions script. To run the HANA tests, the following environment variables need to be set:

$ export RUN_HANA_TESTS=yes
$ export HANA_CONNECTION_STRING="hdb://myuser:mypassword@something.hanacloud.ondemand.com:443?TLSInsecureSkipVerify"

Documentation

Overview

Package hana is a placeholder for the SAP HANA database. The hana provider is provided by the provider.Hana provider please consult that for information on how to use it. please note that the provider type will be mvt_hana