Methods, devices and computer software for facilitating searching and display of locations relevant to a digital map
A portable electronic device is disclosed comprising data processing means and a data repository containing: data records representative of locations relevant to or within a digital map; and data representative of an index associating words contained in the data records with the records in which those words appear. The device further comprises means for, in relation to a received search query including a search string, processing the search string to provide one or more search words; querying the index to identify data records containing the or each search word; and generating a rank for each of the one or more identified data records indicative of the relevance of each identified data record to the search query.
1. A portable electronic device comprising:
one or more processors;
a data repository containing:
data records representative of locations relevant to or within a digital map, wherein each data record is associated with a record identifier comprising a first portion and a second portion: the first portion being a location reference and the second portion being a reference or pointer to information in the data record; and
data representative of an index associating words contained in the data records with the record identifiers associated with the data records in which those words appear; and
a computer readable medium comprising instructions which, when executed by the one or more processors, cause the electronic device, in relation to a received search query including a search string derived from user input on a user interface of the electronic device and a search center derived from a user selected location or from a current location received from a location sensor, to:
process the search string to provide one or more search words;
query the index to identify one or more identified data records containing the or each search word;
determine a distance from the search center for each of the one or more identified data records based on the location reference of the record identifier;
generate a rank for each of the one or more identified data records indicative of the relevance of each identified data record to the search query, the generating including calculating a score for each of the one or more identified data records based on words in that identified data record, the calculating including adjusting penalties used for words when calculating scores for identified data records that represent addresses based on distances for the identified data records that represent addresses; and
cause the display of the results of the search query on a display of the electronic device in rank order.
2. The portable electronic device of claim 1 , wherein the instructions further cause the electronic device, when processing the search string, to perform one or more of:
splitting the search string into words; and
normalising the words.
3. The portable electronic device of claim 2 , wherein normalising the words includes one or more processing steps that account for irregularities in the content of the search string, the processing steps including one or more of:
converting all letters to lower case;
removing accents from letters;
replacing a sequence of the same letter by a single letter;
replacing single letters with other letters; and
replacing words and abbreviations with standard abbreviations.
4. The portable electronic device of claim 2 , wherein the index contains normalised versions of the words contained in the data records and the search string is processed to normalise the words contained therein using the same normalisation rules used in the generation of the index.
5. The portable electronic device of claim 1 , wherein the instructions further cause the electronic device, when querying the index to identify the one or more identified data records containing the or each search word, to:
for each search word, find a set of matching records from the index; and
determine the intersection of the sets of records to provide the records that match all words.
6. The portable electronic device of claim 1 , wherein the instructions further cause the electronic device to:
rank the one or more identified data records based on their scores; and
if two of the one or more identified data records have a same score, reconcile their rank ordering based on a distance from the search center, otherwise rank the two identified data records in a random order.
7. The portable electronic device of claim 1 , wherein calculating the score for each of the of the one or more identified data records includes starting from a starting score and one or more of:
subtracting a penalty from the score for each word contained in the search string not exactly matched to a word contained in that identified data record;
subtracting a penalty from the score for a structural difference between the search words arranged in the search string and how the words appear in that identified data record, including incorrect word order and word gaps; and
subtracting a penalty from the score for each unmatched word contained in a component of that identified data record for which there is a word matching a search word.
8. The portable electronic device of claim 1 , wherein generating the rank for each of the one or more identified data records representing an address includes:
not ranking that identified data record if there is no search word matched against a word in the index contained in a street name of the identified data record.
9. The portable electronic device of claim 7 , wherein generating the rank for each of the one or more identified data records representing a place of interest (POI) includes one or more of:
not ranking that identified data record if there is no search word matched against a word in the index contained in the one of the components of that identified data record representing the name of the POI, the brand name of the POI or the POI category; and
not subtracting a penalty from the score for each unmatched word contained in a component for which there is a word matching a search word.
10. The portable electronic device of claim 1 , wherein the index includes tuples one for each word of the set of words contained in the data records relating each of said words to the respective record identifiers of all the records in which those words appear.
11. The portable electronic device of claim 1 , wherein each data record represents either an address or a Place of Interest (POI).
12. The portable electronic device of claim 11 , wherein the data records contain one or more of the following components or data indicative thereof: street name; place name; postal code; country code; POI name; POI brand name; POI address; and POI category code.
13. The portable electronic device of claim 1 , wherein the search string is derived from a single field free-text string input by the user on the user interface.
14. The portable electronic device of claim 1 , wherein adjusting the penalties used for words when calculating the score for each of the one or more identified data records includes at least one of:
reducing penalties for identified data records having a distance smaller than a first distance; and
increasing penalties for data records having a distance larger than a second distance.
15. The portable electronic device of claim 1 , wherein calculating the score for each of the one or more identified data records includes:
adding a bonus to the score for that identified data record when there is a word match with a center of settlement based on properties of the center of settlement and a distance of the center of settlement from the search center.
16. A method of operating a portable electronic device comprising one or more data processors and a data repository containing: data records representative of locations relevant to or within a digital map, wherein each data record is associated with a record identifier comprising a first portion and a second portion: the first portion being a location reference; and the second portion being a reference or pointer to information in the data record; and data representative of an index associating words contained in the data records with the record identifiers associated with the data records in which those words appear, the method comprising:
in relation to a received search query including a search string derived from user input on a user interface of the electronic device and a search center derived from a user selected location or from a current location received from a location sensor:
processing the search string to provide one or more search words;
querying the index to identify one or more identified data records containing the or each search word;
determining a distance from the search center for each of the one or more identified data records based on the location reference of the record identifier;
generating a rank for each of the one or more identified data records indicative of the relevance of each identified data record to the search query, the generating including calculating a score for each of the one or more identified data records based on words in that identified data record, the calculating including adjusting penalties used for words when calculating scores for identified data records that represent addresses based on distances for the identified data records that represent addresses; and
causing the display of the results of the search query on a display of the electronic device in rank order.
17. The method of claim 16 , wherein adjusting the penalties used for words when calculating the score for each of the one or more identified data records includes at least one of:
reducing penalties for identified data records having a distance smaller than a first distance; and
increasing penalties for data records having a distance larger than a second distance.
18. The method of claim 16 , wherein calculating the score for each of the one or more identified data records includes:
adding a bonus to the score for that identified data record when there is a word match with a center of settlement based on properties of the center of settlement and a distance of the center of settlement from the search center.
19. A non-transitory computer readable storage medium storing instructions that, when executed by one or more data processors of an electronic device that includes the one or more data processors and a data repository containing: data records representative of locations relevant to or within a digital map, wherein each data record is associated with a record identifier comprising a first portion and a second portion: the first portion being a location reference; and the second portion being a reference or pointer to information in the data record; and data representative of an index associating words contained in the data records with the record identifiers associated with the data records in which those words appear, cause the electronic device to perform a method comprising:
in relation to a received search query including a search string derived from user input on a user interface of the electronic device and a search center derived from a user selected location or from a current location received from a location sensor:
processing the search string to provide one or more search words;
querying the index to identify one or more identified data records containing the or each search word;
determining a distance from the search center for each of the one or more identified data records based on the location reference of the record identifier;
generating a rank for each of the one or more identified data records indicative of the relevance of each identified data record to the search query, the generating including calculating a score for each of the one or more identified data records based on words in that identified data record, the calculating including adjusting penalties used for words when calculating scores for identified data records that represent addresses based on distances for the identified data records that represent addresses; and
causing the display of the results of the search query on a display of the electronic device in rank order.
20. The non-transitory computer readable storage medium of claim 19 , wherein adjusting the penalties used for words when calculating the score for each of the one or more identified data records includes at least one of:
reducing penalties for identified data records having a distance smaller than a first distance; and
increasing penalties for data records having a distance larger than a second distance.
21. The non-transitory computer readable storage medium of claim 19 , wherein calculating the score for each of the one or more identified data records includes:
adding a bonus to the score for that identified data record when there is a word match with a center of settlement based on properties of the center of settlement and a distance of the center of settlement from the search center.