GS+ produces 2d and 3d maps of spatial data following interpolation. The data to be mapped come from kriging or IDW analysis, and are thus contained in interpolation output files. Maps can be displayed in a variety of ways with a variety of different contouring schemes, 3-dimensional maps can be rotated on the fly, and both 2-dimensional and 3-dimensional maps can be zoomed to more closely view a transition or other map feature. Additionally, sample postings (original data locations) can be displayed, and estimation standard errors can be mapped for input files that have been saved in the standard GS+ format.
• Select – allows you to choose the file with the data to be mapped. The default file extension will correspond to the selected file format (e.g. .krg for GS+ format), although a file with any extension can be selected.
• View – view the selected file in the View File window.
• File Format – specify the format to use to read the input file. Files with a .krg, .idw, .blk, or .pun extension are assumed to be in GS+ format. The format specified in this field will override any assumed format:
• GS+ Krig format (.krg) – in this format a header area defines the interpolation grid, variate names, and other information about the file needed to initiate mapping later, and the data records include for each X and Y Coordinate location that is kriged the interpolation or Z-estimate, the standard deviation of the Z-estimate, and the number of neighbors that were used to make the estimate.
• Surfer Grid format (.grd) – in this format a short header area defines information needed for mapping, and the data is written as a continuous stream of Z-estimates beginning from a specific corner of the interpolation grid. The standard deviation of the estimate and the number of neighbors used for interpolation are not included in this format. This format is compatible with Golden SoftwareSurfer mapping program. Note that this format is not the same as the Surfer XYZ Input file format.
• ArcInfo or ArcView Format (.asc) – this is similar to the Surfer format but the header area is formatted differently and the Z-estimates are written in a pattern that begins from a different corner of the interpolation grid. The standard deviation of the estimate and the number of neighbors used for interpolation are not included in this format. Also for this format, the x and y interpolation intervals must be the same (you can set them to be the same from the Interpolation Grid dialog window). This format is compatible with ESRIArc-Info Geographic Information System.
• GSLib Format (.out) – this format is similar to the GeoEas input format. A long first record contains coordinate interval information that is read by GS+ when mapping GSLib files. The second record of the file specifies three header records named “estimate,” “estimation variance” (or “standard deviation”), and “neighbors.” Records that follow are in the same order as for Surfer® , but there are three fields per record (estimate, estimation error, and number of neighbors) rather than just one field (the Z-estimate).
• X direction – the range within the file for values in the x (horizontal) direction.
• Y direction – the range within the file for values in the y (vertical) direction; for 1-dimensional data sets this field is blank.
• Z values – the range of estimated Z values in the input file.
• Z SD values – the range of estimation Z standard deviation values in the input file; only files in the GS+ format contain both Z values and Z standard deviation values.
• N (N missing) – the number of valid records in the file and (in parentheses) the number of missing values. The default missing value indicator (e.g. –999.) is specified in the Configuration window; the active missing value indicator for map files is indicated in the Map Contour Intervals window. Missing values are mapped as transparent regions. Exclusive polygons are mapped as missing values, as is any interpolate location for which there is no kriging solution.
• Z values – maps the estimated Z values in the file
• Z standard deviations – maps the estimation Z standard deviations in the file; only files in the GS+ format contain both Z values and Z standard deviation values.
• Sample Posting – map only the original sample locations. Requires the presence of a posting file, which has the same name as the input file but a .pos extension. This file is created during kriging; if it is not present you will not be able to map a sample posting. Note that you may also view a posting map for the active worksheet data from the Data Summary Window.
• 2-d – displays a flat, 2-dimensional map of the data
• 3-d – displays a 3-dimensional map of the data. The height of the map can be adjusted with the Edit Graph command of the Map window; the perspective can be adjusted with the Rotate command of the Map window.
• 1-d – displays 1-dimensional data (e.g. a geographic transect or a time series) as an x-y graph. This choice is not available for 2-dimensional data.
• Contour lines – draws lines between contour intervals
• Color bands – fills the space between contour lines with different colors; colors can be specified from the Define Contour dialog window by pressing Define Contour Levels, below.
• Smoothing – apply slight smoothing to the data to improve visualization.
• Solid pedestal – for a 3-d map fill in the area beneath the surface with a solid color.
• Wireframe – for 3-d maps, drapes an x-y grid over the surface.
• Wireframe Weave – specifies the density of the wireframe grid. A weave of 0 puts a grid line at every data row and column; a weave of 1 skips one row/column, a weave of 2 skips 2, etc.
• Number – the number of contour levels to put on the map.
• Define – brings up the Map Contour Intervals dialog window that allows you to set break points for individual intervals and colors for contour bands.
• Show legend – displays the contour legend next to the map.
• Continuous vs. Stepped – display legend as continuous scale with values next to break points (e.g. between color bands) or display legend as stepped format, with values next to boxed colors.
• Contour lines – project contour lines above the surface onto the ceiling of the plot (3d maps only).
• Color bands – project color bands onto the ceiling of the plot (3d maps only).
• Contour lines – project contour lines beneath the surface onto the floor of the plot (3d maps only).
• Color bands – project color bands onto the floor of the plot (3d maps only).
• X axis – place a vertical grid line along the back walls of the 3d plot x axis.
• Y axis – place a vertical grid line along the back wall of the 3d plot y axis.
• Z axis – place horizontal grid lines along the back walls of 3d plots.
Create the map in a Map Image window.
Close the Map window and exit.