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# 

# LSST Data Management System 

# 

# Copyright 2008-2017 AURA/LSST. 

# 

# This product includes software developed by the 

# LSST Project (http://www.lsst.org/). 

# 

# This program is free software: you can redistribute it and/or modify 

# it under the terms of the GNU General Public License as published by 

# the Free Software Foundation, either version 3 of the License, or 

# (at your option) any later version. 

# 

# This program is distributed in the hope that it will be useful, 

# but WITHOUT ANY WARRANTY; without even the implied warranty of 

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

# GNU General Public License for more details. 

# 

# You should have received a copy of the LSST License Statement and 

# the GNU General Public License along with this program. If not, 

# see <https://www.lsstcorp.org/LegalNotices/>. 

# 

import esutil 

 

 

class HtmIndexer: 

"""Manage a spatial index of hierarchical triangular mesh (HTM) 

shards. 

 

Parameters 

---------- 

depth : `int` 

Depth of the HTM hierarchy to construct. 

""" 

def __init__(self, depth=8): 

self.htm = esutil.htm.HTM(depth) 

 

def getShardIds(self, ctrCoord, radius): 

"""Get the IDs of all shards that touch a circular aperture. 

 

Parameters 

---------- 

ctrCoord : `lsst.geom.SpherePoint` 

ICRS center of search region. 

radius : `lsst.geom.Angle` 

Radius of search region. 

 

Returns 

------- 

results : `tuple` 

A tuple containing: 

 

- shardIdList : `list` of `int` 

List of shard IDs 

- isOnBoundary : `list` of `bool` 

For each shard in ``shardIdList`` is the shard on the 

boundary (not fully enclosed by the search region)? 

""" 

shardIdList = self.htm.intersect(ctrCoord.getLongitude().asDegrees(), 

ctrCoord.getLatitude().asDegrees(), 

radius.asDegrees(), inclusive=True) 

coveredShardIdList = self.htm.intersect(ctrCoord.getLongitude().asDegrees(), 

ctrCoord.getLatitude().asDegrees(), 

radius.asDegrees(), inclusive=False) 

isOnBoundary = (shardId not in coveredShardIdList for shardId in shardIdList) 

return shardIdList, isOnBoundary 

 

def indexPoints(self, raList, decList): 

"""Generate shard IDs for sky positions. 

 

Parameters 

---------- 

raList : `list` of `float` 

List of right ascensions, in degrees. 

decList : `list` of `float` 

List of declinations, in degrees. 

 

Returns 

------- 

shardIds : `list` of `int` 

List of shard IDs 

""" 

return self.htm.lookup_id(raList, decList) 

 

@staticmethod 

def makeDataId(shardId, datasetName): 

"""Make a data id from a shard ID. 

 

Parameters 

---------- 

shardId : `int` 

ID of shard in question. 

datasetName : `str` 

Name of dataset to use. 

 

Returns 

------- 

dataId : `dict` 

Data ID for shard. 

""" 

if shardId is None: 

# NoneType doesn't format, so make dummy pixel 

shardId = 0 

return {'pixel_id': shardId, 'name': datasetName}