Cartographica is commonly used to take data from a number of sources and provide visual interpretations as well as facilitate analysis of that data. As such, most data comes into Cartographica by importing it from other sources (as opposed to data that is created directly in the program—for that, see Creating Data).
Cartographica imports data from many sources. Using algorithms created by the ClueTrust team and by the folks who create, maintain, and contribute to GDAL, Cartographica is able to bring in data from an enormous number of sources, including (but not limited to):
The types of files you will use as source data will vary depending upon what you have available and what specific needs you have. The general kinds of files that Cartographica can import are:
Vector files contain geospatial information and often have accompanying field data that describes the data in the files
To import a Vector file into a Cartographica document, select Import Vector File from the File menu and then select the vector file when prompted. If you have more than one file to import, you can either select multiple items during this import, or import another file after the first one.
Relatively speaking, Vector imports are quite straightforward. There are no parameters, nor are there any additional specifications. Data loaded from these files are inserted into the Cartographica system as points, lines, or polygons (as appropriate) and any per-entity data is added to the entities as necessary.
For shapefiles, Cartographica attempts to figure out what kind of encodings are used in the files by first checking for a ".cpg" file (which will be written by ESRI's products when attempting to write out files that don't conform to specifications in the DBF format), then looking at the LDID inside of the ".dbf" file itself. If that fails, the presumption is that the data is in ISO Latin 1, which is the default for older files. We have confirmed success working with UTF-8 and many other character sets, but since not all characters are represented in the schemes other than UTF-8, there is the potential for losing some data when exporting to other character formats.
In the case of GML and KML, the imported data is presumed to be Unicode UTF-8 (unless specified otherwise in the file itself, since there exist ways to do that in these XML-based formats).
Raster files contain data whose form is that of samples in some form of matrix. The most common example of this kind of file is an image file (such as a JPEG). In these files, the data provided are color information and the matrix is the frame of the picture.
To import a Raster file into a Cartographica document, select Import Raster File from the File menu and then select the raster file when prompted. If you have more than one file to import, you may either select multiple items during this import, or import another file after the first one.
Raster data, when imported, is more complex. In some cases, it is not georeferenced
Cartographica can import text files that contain tables as geospatial and data sources. Cartographica can use text files (either CSV or TSV) to provide three different types of data:
Upon selecting Import Table Data from the File menu, Cartographica will prompt for the file and then will present a window that describes the format of the file and requests that you determine how it should interpret the data as it is read. On the right side of the window, indicate how the data is to be interpreted. Depending on this selection, the data in the left side of the window takes on a different meaning.
Import Map
The Import Map is used to define the relationship between fields within the file or database that is being imported and the layer that they are being imported into. Each use is described below with specifics related to the interpretation that style of import will use. The Field Name is the name of the field based either on the initial line of the file or the database source that the data is coming from. The type is either the explicit type which is stated by the database or the implicit type that Cartographica determined by looking at the contents of the file. Map To defines the column that this field will map to in the resultant layer. If you are importing to a new layer, then your choices here will be limited to "New Column" or items appropriate for the Geocode or Coordinate import. If you are importing to an existing layer, you will also have the choice to map to an existing field. For each type of import, read the appropriate section for further details on how the Map is used.
Address data can be geocoded using any valid geocoding service available to Cartographica. Selection of the geocoding service is via the standard means, but one that is selected, the import window allows you to assign specific columns to particular attributes in the geocoding. For example, a column named "Street" may map to the "Address" field. In some cases, you may have incomplete postal addresses (i.e. they may be missing the City, State, or Country attributes). In these cases, you can put values in the City, State, and Country boxes in the Geocode pane in order to set (or provide defaults for) values in the table. Any additional data may be ignored or added to the data in Cartographica.
Coordinate data may be loaded directly into Cartographica as Point data. When the Coordinates pane is selected in the load window, you can use the "Map To" column to indicate to Cartographica which columns contain X or Y data (Longitude or Latitude respectively) as well as the altitude and time data that corresponds to the points in the file. Any additional data may be ignored or added to the data pane in Cartographica.
At times it may be necessary to add more data to an existing layer by cross-referencing that data with another table. Cartographica can also load this kinds of non-geospatial data by performing a non-geospatial join between an existing layer and new data. By using the "Map To" column to map data in the table file to existing data in the target layer, you can use these (one or more) entries as keys for the join. All other data (not set to be ignored) will be added as columns in the target layer. If more than one column is selected for the join, they will be taken as a logical "and" and will serve as a compound key to the data. Thus, selecting for a match in Color and Size would mean that new data would only be added to each row whose (color,size) tuple is equal to any (color,row) tuple that appears in the target layer.
Cartographica supports loading data directly into the system from a wide variety of GPS receivers. Documentation for specific receivers is in another chapter. In general, the mechanism is to use the Acquire GPS Data… command from the File menu and then select which elements to load into the system. Imported data is represented as follows:
| Tracks | Loaded as lines with each line containing a full track and missing data being represented by discontinuous lines. Altitude is used as the Z coordinate. Time is used as the M coordinate. |
| Waypoints | Loaded as individual points, with each point containing as much data as is available, Z coordinates are set to altitude if available. |
| Routes | Loaded as continuous lines with each waypoint represented by a single point in the line. Altitude is loaded in the Z coordinate if available. M is ignored. |
Additional data types may be available (such as Laps or exercise units) which will be loaded as data without features into a layer.
Acquiring database information works very similarly to Importing Text Files, except that instead of reading the data from a data file, it is read using ODBC—providing compatibility with a wide variety of file formats and database systems (including, but not limited to: Oracle, MySQL, PostgreSQL, and many others).
NOTE: At this time there are compatibility problems with 64-bit applications and most ODBC drivers. If you plan to import data with ODBC, please visit the ClueTrust Knowledgebase and read the article on ODBC.