Finding and reading data

#Search

Search looks for text in the features of the app's layers — a name, a number, a code. Type at least two characters; accents and capitals do not matter, and a part of a word is enough. Results are grouped by layer (up to 10 per layer); click one to zoom to it and highlight it.

Search looks in the layers' text fields that the app's builder chose for searching. It does not look up place names or coordinates.

#Identify

Click anything on the map: a card opens next to the pointer with the layer's name, a photo if the feature has one, and its first attributes. See all in the panel opens the Identify panel with everything that was under the click, layer by layer. The card closes when the map moves.

Some raster layers answer too — a terrain model says the Altitude at the point, a classified map its Class.

#The attribute table

Attribute table in the rail (or in a layer's options) opens a layer's features as a table under the map.

• Choose the layer at the top left. On map beside it switches the layer on or off without going back to the layer list.
• Click a column's name to sort by it; click again to reverse. Shift-click another column's name to sort by it as well: rows that are equal in the first column are put in order by the second, and so on. While the table is sorted by more than one column, small numbers 1, 2… beside the arrows show the order; Shift-click a sorted column again to reverse it, and click any name without Shift to sort by that column alone.
• Previous / Next move through the rows, 50 at a time.
• Zoom to on a row shows that feature: it blinks on the map and stays outlined. If the layer is off, it is switched on.
• Double-click a row to do the same: the row is selected and the map goes to its feature.
• Click a row to select it; Ctrl-click (Cmd on a Mac) adds a row or takes it away, and Shift-click selects the rows between it and the last one clicked. The box at the head of the first column selects every row of the layer, or none. Rows selected in the table are the selection on the map, and features selected on the map are marked in the table, so CSV and the other selection tools work on either.
• When features of the layer are selected, Selection only shows just those. Switch selects the rows that were not selected and unselects the others, as Switch selection does in other GIS programs; Clear unselects every row of the layer.
• Drag a column's header to put it elsewhere, and the edge of a header to change its width; a double click on the edge gives the column back its natural width. The column's menu (its small arrow) can also move it, and Reset columns puts every column back.
• Columns, in the table's toolbar, lists the layer's columns with a box each: untick a column to take it out of the table, tick it to bring it back, or Show all. Hide column in a column's menu does the same for one. Hiding changes only your view: the data, the other people's tables and exports are not affected.
• Freeze up to this column, in a column's menu, keeps the columns from the first to that one in place while the others scroll sideways — useful for keeping a name or a number in view on a wide layer. Unfreeze columns lets them scroll again.
• Cartema remembers the columns of each layer for you: their order, widths, the ones you hid and the ones you froze.
• The table can float over the map (Float the table over the map) and be moved and resized, or be docked under it again.

#Querying the table

Query, in the table's toolbar, shows only the rows that meet conditions, as Select by attributes does in other GIS programs. Choose a Field, an Operator — Is, Is not, Less than, At most, Greater than, At least, Contains, Starts with, Is empty, Is not empty or Is one of (values separated by commas, semicolons or lines) — and a Value. Add up to five conditions with + Condition, matched All or Any, and Apply.

While a query is on, the table lists only the matching rows, and the Query button is marked. Select these (with the number of matching rows) makes them the selection on the map, so the selection tools, CSV and Export of Selected rows work on them. Clear removes the query; closing the bar keeps it.

#Column statistics

Statistics, in a column's menu, summarises the column's values:

• for a number column: Rows, With a value, Empty, Minimum, Maximum, Sum, Mean and Standard deviation, with a small chart of how the values are spread between the minimum and the maximum (point at a bar to see its range and count);
• for a date column: the Earliest and the Latest date, and how many rows have one;
• for a text or yes/no column: how many Different values there are, and the 20 most frequent with how many rows have each.

Under Rows, choose what is counted: the Whole layer, the Query's rows while a query is on, or the Selected rows while some are selected. The statistics open on what the table is showing. Only rows you can see in the app are counted, and only columns the table shows you can be summarised.

#Exporting from the table

The table's toolbar takes its rows away, all of them or only the selected ones. Under Rows, All rows is every row the layer shows in this app; Selected rows is the rows selected in the table or on the map, and can be chosen only while some are selected.

• Export saves the rows as a file — GeoPackage, Shapefile (zip), GeoJSON, KML, CSV or DXF — in longitude and latitude or one of the app's grids, as Export… in a layer's menu does (see My layers, files and exports). The file is prepared in the background and offered as Download.
• Save as layer copies the rows and their attributes into a new layer. My layers makes it a private layer of yours, listed in this app; the app's data is not touched. Where the app's data can be edited from the map, its editors can also choose This app's layers: the new layer is the workspace's, editable, placed just above the original, and the original stays as it is.

The buttons are there for whoever may use them: Export for the people who may export the layer, Save as layer for the people who may make layers of their own in the app. Either way, only rows you can see in the app leave it — a layer the app shows for one area exports and copies that area's rows, however many were asked for — and a field the app hides from the table is left out of a viewer's file.

#Selecting features

Selection picks features to work with — to count them, see them in the table, or export them. Only layers that are switched on can be selected, and Cartema counts from the data itself, not from what is drawn on screen.

Mode	How
Point	Click a feature
Rectangle	Drag a rectangle over the map
Polygon	Click around an area, then Finish
Attribute	Choose a layer and write conditions — for example Area Greater than 100. Up to five conditions, matched All or Any
Layer	Features that intersect, are inside, contain or are within a distance of the features of another layer — or only of those selected there

The result says how many features were selected, layer by layer. For each layer you can open it in the table, zoom to it, or export it with CSV. Clear empties the selection.

#Exporting to a spreadsheet

CSV, next to a layer in the selection result, downloads the selected features and their attributes as a CSV file that opens directly in Excel (semicolon-separated, with accents intact). An export holds at most 20 000 rows.