Troubleshooting

CSV Editor attempts to cope with some of the common variations on input GIS files. However, there are many reasons why an input file will not correctly parse. Here are some guidelines for input data.

Raster Import

Raster data must follow an exact grid, meaning there must be an equal number of columns in each row of the data. Each 'cell' is interpreted as one pixel of depth data, and easting is considered to increase going along a row of data. Cells must be equally spaced.

Many files with extensions such as CSV, TXT, ASC, XYZ, etc., in fact, contain vector data, and in those cases, it is appropriate to use the XYZ vector import tool. If an input file has three columns of text data, it is very likely a vector XYZ file rather than a raster. There are also raster gridded XYZ files (where the given points are located on a regular grid). However, CSV Editor also imports these using the XYZ vector import tool.

ESRI Ascii grid files commonly (but not exclusively) use the .ASC extension. There are several variations in the file header data, such as offering different X and Y cell sizes (using the DX and DY parameters in place of CELLSIZE), or using latitude/longitude coordinates instead of easting and northing given in metres. CSV Editor will attempt to interpret the input file, but not all header variations are known, and some manual editing may be necessary. The delimiter for ESRI Ascii grid files is the space character (ASCII code 32).

Vector Import

Whether the input file is .shp or .xyz, the quality of the generated raster will depend on the spacing of the input points. Best results are achieved where the given points are spread relatively evenly over the project area, and there are no large areas where no points are found. Areas at the edge of the map where there are no points will be shown in grey and will not contribute to any calculations. Increasing the size of the output raster gives greater resolution, at the expense of more calculation time, and the added detail may not be warranted by the quality of the input data.

Shapefile Import

Both a .SHP and .DBF file are required. The input shapes are interpreted as contours, and the height/depth of each contour is read from one of the numerical fields in the .DBF file. Input shapes where the height/depth data is given by the z point coordinate are not currently supported.

XYZ Import

There are several different ways of expressing XYZ data, and XYZ files may also use a variety of extensions. CSV Editor requires data to be comma or tab-separated, in three columns, showing X, Y, and Z coordinates as shown in the page CSV Editor Vector Import. Alternatively, the columns may be ordered Z, X, Y. Ignore any non-numerical header rows by clicking in the Ignore column. The distribution of the given points in space is not important beyond the guidelines given above, so gridded XYZ files will import as well as partially gridded files and files with unstructured/unsorted point spacing.