private void PaintBtn_Click(object sender, EventArgs e)
        {
            if (sectorSelected && parent.pop.curTerrain != null)
            {
                var curSector = parent.pop.curTerrain._sectorArray[selectedX][selectedY];
                var curPlanet = parent.pop.curPlanet;
                PlanetObj.planet_type planetType = PlanetObj.planet_type.tUnknown;
                if (curPlanet != null)
                {
                    planetType = curPlanet.planetType;
                }
                bool updated = true;

                switch (planetType)
                {
                case PlanetObj.planet_type.tRock:
                case PlanetObj.planet_type.tGasGiant:
                case PlanetObj.planet_type.tSubGasGiant:
                case PlanetObj.planet_type.tSubSubGasGiant:
                case PlanetObj.planet_type.tAsteroids:
                case PlanetObj.planet_type.tVenusian:
                    updated = false;
                    break;

                case PlanetObj.planet_type.tTerrestrial:
                case PlanetObj.planet_type.t1Face:
                    if (curSector.surfaceType == SectorObj.SurfaceType.Rock)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Grass;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Grass)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Dirt;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Dirt)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Ice;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Ice)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Water;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Water)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Rock;
                    }
                    updated = true;
                    break;

                case PlanetObj.planet_type.tMartian:
                    if (curSector.surfaceType == SectorObj.SurfaceType.Rock)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Dirt;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Dirt)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Ice;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Ice)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Rock;
                    }
                    updated = true;
                    break;

                case PlanetObj.planet_type.tWater:
                    if (curSector.surfaceType == SectorObj.SurfaceType.Rock)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Grass;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Grass)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Dirt;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Dirt)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Water;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Water)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Ice;
                    }
                    break;

                case PlanetObj.planet_type.tIce:
                    if (curSector.surfaceType == SectorObj.SurfaceType.Rock)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Ice;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Ice)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Rock;
                    }
                    break;

                case PlanetObj.planet_type.tUnknown:
                    if (curSector.surfaceType == SectorObj.SurfaceType.Rock)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Grass;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Grass)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Dirt;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Dirt)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Ice;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Ice)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Water;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Water)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Gas;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Gas)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Unknown;
                    }
                    else if (curSector.surfaceType == SectorObj.SurfaceType.Unknown)
                    {
                        curSector.surfaceType = SectorObj.SurfaceType.Rock;
                    }
                    updated = true;
                    break;
                }

                if (updated)
                {
                    curSector.dirty = true;
                    View sectorView = gridView.FindViewWithTag(curSector.Id);
                    if (sectorView != null)
                    {
                        var imageView = sectorView.FindViewById <ImageView>(Resource.Id.backgroundImage);
                        Koush.UrlImageViewHelper.SetUrlDrawable(imageView, curSector.DefaultUrl, Resource.Drawable.Icon);
                    }
                    isDirty = true;
                }
            }
        }