Make spatial completion ponderation f(level, population) with priority on level #811
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udata/core/spatial/search.py
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| return 2147483647 | ||
| def compute_weight(cls, zone): | ||
| ''' | ||
| Give a weight to the zone according its administrative level first |
udata/core/spatial/search.py
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| and then its population. | ||
| ''' | ||
| # Each level give give a step | ||
| level = min(admin_levels.get(zone.level, ADMIN_LEVEL_MAX), 1) |
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No: here to avoir devision by zero so I prefer explicit 1 over an ADMIN_LEVEL_MIN which can be 0.
udata/core/spatial/search.py
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| Give a weight to the zone according its administrative level first | ||
| and then its population. | ||
| ''' | ||
| # Each level give give a step |
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Can you put boundaries like with population to have an idea?
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Done but I don't think it brings any value because this is relative scoring. What matter is that admin level weight more that population.
udata/core/spatial/search.py
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| ''' | ||
| # Each level give give a step | ||
| level = min(admin_levels.get(zone.level, ADMIN_LEVEL_MAX), 1) | ||
| level_weight = (ADMIN_LEVEL_MAX / level) * 10 * PONDERATION_STEP |
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Why not set PONDERATION_STEP to 10000 in that case?
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Because, of the use later: for the mathemtical explnation, th * 10 is here to dilate the (ADMIN_LEVEL_MAX / level) which is 1 < f(level) < inf. The factor is only here to ensure steps are not overlapping too much. If I touch the PONDERATION_STEP, the overlapping doesn't change, it is dilated too.
udata/core/spatial/search.py
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| level_weight = (ADMIN_LEVEL_MAX / level) * 10 * PONDERATION_STEP | ||
| # Population gives 0 < weight < 1000 to rank between level steps only | ||
| population = min(max(0, zone.population), POPULATION_MAX) | ||
| population_weight = (population / POPULATION_MAX) * PONDERATION_STEP |
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Mmh ok got it for the ponderation, in that case why not below directly to the sum?
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Because (population / POPULATION_MAX) < 1 so population_weight < PONDERATION_STEP
udata/core/spatial/models.py
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| @@ -24,6 +24,9 @@ | |||
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| ADMIN_LEVEL_MIN = 1 | |||
| ADMIN_LEVEL_MAX = 110 | |||
| # Max known population for a zone | |||
| # World population is 6772425850. | |||
| POPULATION_MAX = 2147483647 | |||
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I think it comes from an ES limitation given that it's the maximum positive value for a 32-bit signed binary integer. So it's not related to the population.
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As a consequence, it should be the max for the level weight too.
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OK, so not a problem here because the max computed value is far from it.
I changed for the world population (approximative) so the number means something and the algo works on any zone
This PR try to enhance spatial completion for zones with short name and few population (or no population data available) by taking in account administrative level and area.
The algorithm gives priority to the administrative level and then optionally to the population.
It could be enhanced with the area too which is also available.