The legacy tokenizer implements the analysis algorithms of older Nominatim
versions. It uses a special Postgresql module to normalize names and queries.
-This tokenizer is currently the default.
+This tokenizer is automatically installed and used when upgrading an older
+database. It should not be used for new installations anymore.
+
+### Compiling the PostgreSQL module
+
+The tokeinzer needs a special C module for PostgreSQL which is not compiled
+by default. If you need the legacy tokenizer, compile Nominatim as follows:
+
+```
+mkdir build
+cd build
+cmake -DBUILD_MODULE=on
+make
+```
+
+### Enabling the tokenizer
To enable the tokenizer add the following line to your project configuration:
The ICU tokenizer uses the [ICU library](http://site.icu-project.org/) to
normalize names and queries. It also offers configurable decomposition and
abbreviation handling.
+This tokenizer is currently the default.
To enable the tokenizer add the following line to your project configuration:
``` yaml
normalization:
- ":: lower ()"
- - "ß > 'ss'" # German szet is unimbigiously equal to double ss
+ - "ß > 'ss'" # German szet is unambiguously equal to double ss
transliteration:
- !include /etc/nominatim/icu-rules/extended-unicode-to-asccii.yaml
- ":: Ascii ()"
The normalization and transliteration sections each define a set of
ICU rules that are applied to the names.
-The **normalisation** rules are applied after sanitation. They should remove
+The **normalization** rules are applied after sanitation. They should remove
any information that is not relevant for search at all. Usual rules to be
applied here are: lower-casing, removing of special characters, cleanup of
spaces.
rendering:
heading_level: 6
+##### clean-housenumbers
+
+::: nominatim.tokenizer.sanitizers.clean_housenumbers
+ selection:
+ members: False
+ rendering:
+ heading_level: 6
+
+##### clean-postcodes
+::: nominatim.tokenizer.sanitizers.clean_postcodes
+ selection:
+ members: False
+ rendering:
+ heading_level: 6
+
+##### clean-tiger-tags
+
+::: nominatim.tokenizer.sanitizers.clean_tiger_tags
+ selection:
+ members: False
+ rendering:
+ heading_level: 6
+
+#### delete-tags
+
+::: nominatim.tokenizer.sanitizers.delete_tags
+ selection:
+ members: False
+ rendering:
+ heading_level: 6
+
+#### tag-japanese
+
+::: nominatim.tokenizer.sanitizers.tag_japanese
+ selection:
+ members: False
+ rendering:
+ heading_level: 6
#### Token Analysis
The token-analysis section contains the list of configured analyzers. Each
analyzer must have an `id` parameter that uniquely identifies the analyzer.
The only exception is the default analyzer that is used when no special
-analyzer was selected.
+analyzer was selected. There are analysers with special ids:
+
+ * '@housenumber'. If an analyzer with that name is present, it is used
+ for normalization of house numbers.
+ * '@potcode'. If an analyzer with that name is present, it is used
+ for normalization of postcodes.
Different analyzer implementations may exist. To select the implementation,
-the `analyzer` parameter must be set. Currently there is only one implementation
-`generic` which is described in the following.
+the `analyzer` parameter must be set. The different implementations are
+described in the following.
##### Generic token analyzer
-The generic analyzer is able to create variants from a list of given
+The generic analyzer `generic` is able to create variants from a list of given
abbreviation and decomposition replacements and introduce spelling variations.
###### Variants
to the analyser configuration.
+##### Housenumber token analyzer
+
+The analyzer `housenumbers` is purpose-made to analyze house numbers. It
+creates variants with optional spaces between numbers and letters. Thus,
+house numbers of the form '3 a', '3A', '3-A' etc. are all considered equivalent.
+
+The analyzer cannot be customized.
+
+##### Postcode token analyzer
+
+The analyzer `postcodes` is pupose-made to analyze postcodes. It supports
+a 'lookup' varaint of the token, which produces variants with optional
+spaces. Use together with the clean-postcodes sanitizer.
+
+The analyzer cannot be customized.
+
### Reconfiguration
Changing the configuration after the import is currently not possible, although