Types for Surface Analysis – Global Mapper

The following types are used in functions related to surface analysis operations as parameters and return values. These types use fixed, numeric constants, which are defined here.

globalmapper.GM_CombineOp_t8

Available operations when combining terrain layers

Values:

GM_CombineOp_Add = 0: Addition
GM_CombineOp_SubtractSigned = 1: Subtraction (Difference) - Signed
GM_CombineOp_SubtractUnsigned = 2: Subtraction (Difference) - Unsigned
GM_CombineOp_Average = 3: Average Elevation
GM_CombineOp_Minimum = 4: Minimum Elevation
GM_CombineOp_Maximum = 5: Maximum Elevation
GM_CombineOp_Multiply = 6: Multiply the values from the layers together
GM_CombineOp_Divide = 7: Divide the First Layer Value by the Second
GM_CombineOp_FilterKeepFirstIfSecond = 8: Filter - Keep First Layer Value only if Second Layer Value Valid
GM_CombineOp_KeepFirstIfGTSecond = 9: Filter - Keep First Layer Value only if Greater Than Second Layer Value
GM_CombineOp_KeepFirstIfLTSecond = 10: Filter - Keep First Layer Value only if Less Than Second Layer Value
GM_CombineOp_KeepFirstIfSecondGTVal = 11: Filter - Keep First Layer Value only if Second Layer Value > Some Value
GM_CombineOp_KeepFirstIfSecondLTVal = 12: Filter - Keep First Layer Value only if Second Layer Value > Some Value
GM_CombineOp_FilterKeepFirstIfNotSecond = 13: Filter - Keep First Layer Value only if Second Layer Value Invalid
GM_CombineOp_CountValid = 14: Count Valid Samples at Each Location

GM_CombineOp_NumTypes = 15

globalmapper.GM_CombineOpFlags_t32

Flags used in the setup structure needed for a grid layer combine operation

Values:

GM_CombineOp_FillGaps = 0x00000001: Fill small gaps in terrain layers
GM_CombineOp_HideProgress = 0x00000002: Hide progress for the operation
GM_CombineOp_FindOverlap = 0x00000004: When counting layers, only count where all layers overlap (1 for valid from all, 0 otherwise)

globalmapper.GM_DensityGridFlags_t32

Flags for density grid generation

Values:

GM_DensityFlags_DisableProgress = 0x00000001: Don’t display a progress dialog

globalmapper.GM_DensityKernelType_t8

Different type of calculation kernels to use for density generation

Values:

GM_KernelType_Gaussian = 0: Gaussian
GM_KernelType_Circle = 1: Circle
GM_KernelType_Epanechnikov = 2: Anechnikov

GM_NumKernelTypes = 3

globalmapper.GM_EqualValueAreaFlags_t32

Flags for the equal-value area operation

Values:

GM_EqualValueArea_ForceRGB = 0x00000001: Use RGB attribute for color attributes even if in palette
GM_EqualValueArea_Coverage = 0x00000002: Just create a coverage layer, so we only care about valid or not
GM_EqualValueArea_FixInvalid = 0x00000004: Automatically chop up any resulting areas that are invalid
GM_EqualValueArea_BluntCorners = 0x00000008: Force the blunting of right angles to avoid invalid areas
GM_EqualValueArea_NoSlope = 0x00000010: Don’t do equal value of slope even if slope shader is used
GM_EqualValueArea_UseElevRange = 0x00000020: The mElevRangeLow/mElevRangeHigh values in GM_EqualValueAreaSetup_t are valid
GM_EqualValueArea_UseSlopeDir = 0x00000040: Use slope direction values
GM_EqualValueArea_BaseElevRangeZero = 0x00000080: make the area ranges based on elevations or slopes start at zero rather than having the bin at zero go +/- mElevDist to either side. For example, with mElevDist=500, you would get ranges of [0,1000),[1000,2000),… rather than [-500,500),[500,1500),…
GM_EqualValueArea_HideProgress = 0x00000100: don’t display the progress bar during the process

globalmapper.GM_GridAlg_t8

Gridding algorithm - Specify what gridding algorithm to use when gridding 3D vector data and point clouds

Values:

GM_GridAlg_TIN = 0: Triangulate and grid, same as normal 3D gridding
GM_GridAlg_BinMinimum = 1: (DTM) Bin the points, use min value (i.e. elevation) in each bin, use a bin size some multiplier of average spacing
GM_GridAlg_BinAverage = 2: Bin the points, use avg value (i.e. elevation) in each bin, use a bin size some multiplier of average spacing
GM_GridAlg_BinMaximum = 3: (DSM) Bin the points, use max value (i.e. elevation) in each bin, use a bin size some multiplier of average spacing
GM_GridAlg_BinMedian = 4: Bin the points. Use median value (i.e. elevation) in each bin.
GM_GridAlg_BinVariance = 5: Bin the points. use variance of value (i.e. elevation) in each bin.
GM_GridAlg_BinFromMaxElev = 6: Bin Lidar points, use attribute value from point with maximum elevation
GM_GridAlg_BinFromMinElev = 7: Bin Lidar points, use attribute value from point with minimum elevation

GM_GridAlg_NumTypes = 8

GM_GridAlg_None = 0xFF: Create a point cloud (don’t grid)

GM_GridAlg_Default = GM_GridAlg_TIN

GM_GridAlg_DefaultLidar = GM_GridAlg_BinMinimum: Default algorithm for only Lidar points

globalmapper.GM_GridGapFillAlg_t8

Gridding gap fill algorithm - specify what gridding algorithm to use when filling gaps

Values:

GM_GapFillAlg_None = 0: No Gap fill at all
GM_GapFillAlg_TinSample = 1: Sample TIN surface triangles (piecewise affine) [only available with GM_GridAlg_TIN]
GM_GapFillAlg_IDW = 2: Inverse weighted distance algorithm
GM_GapFillAlg_Kriging = 3: Kriging
GM_GapFillAlg_NearestNeighbor = 4: Use elevation of nearest valid sample
GM_GapFillAlg_NaturalNeighbor = 5: The neighbor weights are calculated by finding how much of each of the surrounding areas is “stolen” when inserting (x,y) into the Voronoi tessellation

GM_GapFillAlg_NumTypes = 6

GM_GapFillAlg_Default = GM_GapFillAlg_IDW

globalmapper.GM_GridGenFlags_t32

This type represents the different flags available for elevation grid generation

Values:

GM_GridGen_NoConstraints = 0x00000001: Don’t treat area and line boundaries as constraints (i.e. break lines)
GM_GridGen_FlattenAreas = 0x00000002: Flatten 3D areas
GM_GridGen_FillToBounds = 0x00000004: Fill the grid to the full bounding rectangle of the input data and not just to the convex hull
GM_GridGen_IgnoreZeroElevs = 0x00000008: Don’t use features with an elevation value of 0
GM_GridGen_HeightsRelative = 0x00000010: Vector elevations are relative to underlying terrain data (if loaded)
GM_GridGen_CropToAreasIfAllAreas = 0x00000020: If all features are areas, mark everything outside areas as invalid
GM_GridGen_IncludeStreams = 0x00000040: If stream lines are provided assign them elevations from intersecting lines
GM_GridGen_SelAreasOnly = 0x00000080: Only consider selected areas
GM_GridGen_AreaVertexRelativeOnly = 0x00000100: Only the area vertex height is relative to ground, not inside the area
GM_GridGen_RelativeRequireValid = 0x00000200: If GM_GridGen_HeightsRelative is set, don’t grid points if there is no terrain at the location
GM_GridGen_SaveGroundHeight = 0x00000400: If using Lidar field GM_LidarGrid_Height, grid the DSM (digital surface model) by working backwards from calculated heights above ground
GM_GridGen_CreateLidarImage = 0x00000800: If gridding a Lidar field than can potentially be stored as an image or grid (i.e. GM_LidarGrid_Intensity), create an image rather than a grid
GM_GridGen_ApplyLidarBreaklines = 0x00040000: Apply 3D line and 3D area features as breaklines when gridding Lidar data
GM_GridGen_IgnoreTypeFilters = 0x00080000: Ignore any set type filters and grid all 3D features in the provided layer(s)
GM_GridGen_TinAreasOnly = 0x00100000: Only grid 3D area features with TIN geometry (ignore all other features)
GM_GridGen_HideProgress = 0x00200000: Don’t show progress during this operation

globalmapper.GM_GridValType_t8

(DEPRECATED) List of supported grid layouts for GM_CreateCustomElevGridLayer

Values:

GM_GridValType_SInt16 = 0: Each sample is a signed 16-bit integer
GM_GridValType_SInt32 = 1: Each sample is a signed 32-bit integer
GM_GridValType_Float = 2: Each sample is an IEEE 32-bit floating point number

GM_GridValType_NumTypes = 3

globalmapper.GM_PathProfileLOSFlags_t32

Flags to control the behavior of path profile/line of sight analysis

Values:

GM_PathProfile_LOSValid = 0x00000001: Perform line-of-sight analysis
GM_PathProfile_LOSIgnoreEndpoints = 0x00000002: Ignore endpoints when performing line-of-sight analysis (i.e. end points can’t block line of sight)

GM_PathProfile_LOSFromHeightAbsolute = 0x00000004

GM_PathProfile_LOSToHeightAbsolute = 0x00000008: Line-of-sight to height is absolute height above sea level rathern than height above ground
GM_PathProfile_IgnoreEarthCurvature = 0x00000010: Ignore earth curvature in any line-of-sight analysis

globalmapper.GM_RoughnessGridFlags_t32

Flags for roughness grid generation

Values:

GM_RoughnessFlags_DisableProgress = 0x00000001: Don’t display a progress dialog
GM_RoughnessFlags_DontFixInvalid = 0x00000002: Don’t automatically chop up invalid areas to make them valid

globalmapper.GM_RoughnessTable_t

Types of roughness tables for converting color values representing land cover to roughness values

Values:

GM_Roughness_CorineSummer = 0: CORINE Land Cover - Summer
GM_Roughness_CorineWinter = 1: CORINE Land Cover - Winter
GM_Roughness_VCF = 2: Vegetation Continuous Fields (GLCF from MODIS)
GM_Roughness_NLCD = 3: US NLCD (National Land Cover Database)
GM_Roughness_GlobCoverESA2009 = 4: GlobCover ESA 2009 Land Cover Database
GM_Roughness_GlobeLand30 = 5: GlobeLand30 Land Cover Database
GM_Roughness_ESA_CCI = 6: ESA CCI (Climate Change Initiative) Land Cover Database
GM_Roughness_GlobCoverESA2020 = 7: GlobCover ESA 2020 Land Cover Database

GM_Roughness_NumTypes = 8

globalmapper.GM_WatershedFlags_32

Flags for watershed calculations

Values:

GM_Watershed_FillGaps = 0x00000001: Fill small gaps when getting elevation values?
GM_Watershed_CreateAreas = 0x00000002: Should we generate areas coverage the drainage basin for each stream?
GM_Watershed_KeepZeroAtZero = 0x00000004: Keep elevation of zero at zero during depression filling
GM_Watershed_SmoothStreams = 0x00000008: Smooth generated streams?
GM_Watershed_FindRidgeLines = 0x00000010: Find ridge lines rather than streams. This is basically a watershed operation with inverted terrain.
GM_Watershed_AutoStyle = 0x00000020: Automatically style generated stream / ridge lines
GM_Watershed_CalcStrahler = 0x00000040: Specifies whether the Strahler stream order should be calculated and added to stream lines as an attribute