solidity-gis

Solidity GEO

Solidity GEO implements GIS polygon core functions and circle functions.

A polygon contains an array of rings.
Each ring is represented as an array of points. The first point of each ring is always the same as the last point.
Each point contain from two cells first cell is latitude, second cell is longitude.
The polygon consists of int32 array. Where max allowed value for latitude is 90000000 and for longitude is 180000000.
Solidity support only integers so 180000000 will represent 180.000000.
So if you what to store geoPoint(79.123, -110.000287) you have send it like(79123000, -110000287).

A circle contains latitude, longitude and radius.
Latitude and longitude has the same type as in polygon.

Quickstart

• Choose which polygon contract we need LightPolygon.sol or HeavyPolygon.sol. (Light cheaper by gas consumption if it consists of less than 19 points otherwise use Heavy)

• You have to submit to constructor of the contract predefined polygon data. Example: [2, 6, 3, 3, 177200246, 110441952, 25242204, 39802040, 15242224, -39802040, 65000000, 20000000, -51000000, 25000000, -164000000, -4000000]

• Data format:

  • Zero cell contain amount of rings in polygon. (In our example: date[0] == 2)
  • First cell contain the total amount of points in the polygon. (In our example: date[1] == 6)
  • Next N cells contains amount of points in each rings, where N this rings amount. (date[2]... date[2 + date[0]])
  • All other cells contains points of all rings in order of the rings.
    • (In our example first rings points: [177200246, 110441952, 25242204, 39802040, 15242224, -39802040])
    • (In our example second rings points: [65000000, 20000000, -51000000, 25000000, -164000000, -4000000])

• Constrains:

  • Max rings amount in polygon is 255.
  • Min points amount per ring is 3, max points amount depend on gas limit.
  • The sum of the points in the rings should be equal to the total number of points in the polygon.

Polygon functions

 makeImmutable() public

Make this contract immutable. After this functions will be executed
you will not be able to modify any values in this contract.

 addPoints(int32[] memory points, uint8 ringIndex) public

Add points to ring specific by index(Index started from 0).
Constrain: ring must exist, and already contain points.
points param is array of points.
ringIndex param is Index of ring in which points will be added.

 addPoints(int32[] memory points, uint8 ringIndex, uint32 pointNum) public

Add points to ring specific by index(Index started from 0).
Constrain: ring must exist, and already contain points.
points param is array of points.
ringIndex param is index of ring in which points will be added.
pointNum is the number of points(not cells, each point is two cell) from which new will be added.

 removePoints(uint32 amount, uint8 ringIndex, uint32 offset) public

Remove points from ring specific by index(Index started from 0).
Constrain: ring must exist, and contain enough cells to do offset * 2 + amount * 2.
Remember that each point is two cells.
amount param is amount of points to delete(not cells, each point is two cell).
ringIndex param is index of ring from which points will be removed.
offset param is the number of points(not cells, each point is two cell) from which amount of points will be deleted

 addRing(int32[] memory points) public

Create new ring and add points in it. points param is array of points.

 addRing(int32[] memory points, uint8 index) public

Create new ring and add points in it.
Constrain: rings amount must be enough to do offset.
Remember that each point is two cells.
points param is array of points.
index param is the number of cells in rings array in which new ring will be added.

 removeRing(uint8 ringIndex) public

Remove ring and all its points by ring index(Index started from 0).
ringIndex param is index of ring.

 changeContractOwner(address _to) public returns (bool)

Change contract owner to onther address.(Only contract owner can add oracle addresses and make contract immutable, only contract owner can call this function)
Function returns true if contract owner was changed successful.

addOracledAddress(address _oracled) public returns (bool)

Add oracle address. (Only contract owner and oracles are able to change contract state if contract is still mutable, only contract owner can call this function).
Function returns true if oracle address was added successful.

 deleteOracledAddress(address _oracled) public returns (bool)

Delete oracle address. (Only contract owner can call this function)
Function returns true if oracle address was deleted successful.

getPointsByRing(uint8 ringIndex) public view returns (int32[] memory)

Get ring points by ring index.
ringIndex is index of ring.

 getPoints() public view returns (int32[] memory)

Get points of first ring(ring index 0)

 getPointsAmountByRing(uint8 ringIndex) public view returns(uint32)

Get points amount by index ring(Index started from 0).
ringIndex param is index of ring.

 getPointsAmount() public view returns(uint32)

Get total points amount(sum of points in all rings).

 getRingsAmount()

Get rings amount in polygon

 isImmutable() public view returns (bool)

If function returned true then polygon is immutable (no one will be able to change its state).

Circle functions

 getData() public view returns(int32[])

Generate data array with size of 3 elements.
Zero cell contains latitude.
First cell contains longitude.
Second cell contains radius.