How to check for empty string?
Hiking & ActivitiesThe isEmpty() method checks whether a string is empty or not. This method returns true if the string is empty (length() is 0), and false if not. How to check for empty string in js? Answer: Use the === Operator You can use the strict equality operator ( === ) to check whether a string
Defining variables by selection
Hiking & ActivitiesWhat is meant by variable selection? Variable selection means choosing among many variables which to include in a particular model, that is, to select appropriate variables from a complete list of variables by removing those that are irrelevant or redundant. How do you define a selection variable in SAP? Procedure Call up the transaction STVARV
Rasters to PostGIS
Hiking & ActivitiesCan you store raster in PostGIS? The raster data type in PostGIS can be used to store any kind of raster data: images, elevation grids, model outputs, and more. One band, four band, multi-band and anything in between. This flexibility leads some beginners to dump all their imagery into the database as “step one” in
How can I access second (or even third) level attributes in a vector layer and add them to the attribute table?
Hiking & ActivitiesHow do I view attribute tables in QGIS? Open Attribute Table button in the Attributes toolbar. This will open a new window that displays the feature attributes for the layer (figure_attributes_table). According to the setting in Settings ‣ Options ‣ Data sources menu, the attribute table will open in a docked window or a regular
How do algorithms load pieces of maps?
Hiking & ActivitiesHow do map routing algorithms work? Google Maps essentially uses two Graph algorithms – Dijkstra’s algorithm and A* algorithm, to calculate the shortest distance from point A ( Source) to point B ( destination). A graph data structure is essentially a collection of nodes that are defined by edges and vertices. What is mapping algorithms?
SQL query on array data in ArcGIS attribute table
Hiking & ActivitiesHow do I query an attribute table? Selecting records in a table by attributes Click Table Options in the table you want to query and click Select By Attributes . Click the Method arrow and click the selection procedure you want to use. Double-click the field from which you want to select. Click the logical