CODEWITHSUNDEEP
google-mapsmathmapsmappinglatitude-longitude
Ashwini Khare
Ashwini Khare

Reputation: 1675

Given two point's latitude and longitude, computing coordinates of point in between

I'm trying to generate some annotations on a map. Currently, I'm using openstreetmap but the query is general. I have two end points on a map and a corpus of few selected points I would like to highlight.

The two endpoints are given in the form lat, long

<walkSteps>
<distance>9.742464221826811</distance>
<streetName>5th St NW</streetName>
<absoluteDirection>EAST</absoluteDirection>
<stayOn>false</stayOn>
<bogusName>false</bogusName>
<lon>-84.3937361115149</lon>
<lat>33.77692965678444</lat>
<elevation/>
</walkSteps>

<walkSteps>
<distance>508.2608917548245</distance>
<relativeDirection>LEFT</relativeDirection>
<streetName>Fowler St NW</streetName>
<absoluteDirection>NORTH</absoluteDirection>
<stayOn>false</stayOn>
<bogusName>false</bogusName>
<lon>-84.39363494600667</lon>
<lat>33.77692904176358</lat>
<elevation/>
</walkSteps>

My aim is to highlight those points on the map, which are present in the corpus and lie in the line connecting these two points.

How can I go about querying the corpus for the same? Annotating on map given lat, lng is not an issue

Upvotes: 0

Views: 237

Answers (1)

andand
andand

Reputation: 17487

Rounding errors will prevent you from directly doing as you want. What you should be doing instead is determining the great-circle path between the two end points and highlighting those members of the corpus which are within a certain distance of the great circle route. This is known as the cross-track distance or cross-track error. Formulas for computing the cross-track distance can be found at one of the standard reference sites for geospatial equations but there are others as well.. The problem then becomes one of searching for points in the corpus which are close enough to the great circle path between the two end points.

Upvotes: 2

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