Category: Geographic Information Systems

Create additional ‘fields’ in GDB domain system table (GDB_items)?

What is a GDB table? The internal structure of the geodatabase is represented as a series of simple tables called the geodatabase system tables (the tables prefixed with GDB_), which track the contents of each geodatabase. They essentially describe the geodatabase schema that specifies all dataset definitions, rules, and relationships. Which geodatabase repository table stores

Exporting layer to PostgreSQL / Inserts per Transaction

How many inserts per second can Postgres handle? If you’re simply filtering the data and data fits in memory, Postgres is capable of parsing roughly 5-10 million rows per second (assuming some reasonable row size of say 100 bytes). If you’re aggregating then you’re at about 1-2 million rows per second.  How to store large

Advantages either way between GML and Shapefiles?

What are the main advantages of using shapefiles? A primary advantage of shapefiles is that this simple file structure draws faster than a coverage does. This may be why the shapefile data structure was developed for ArcView GIS, a software program that was originally designed for data viewing rather than analysis. What is the difference

Trouble with Hot Spot Analysis (Getis-Ord Gi*) tool in ArcGIS

How to do hotspot analysis in ArcGIS? From the Toolbox navigate to Spatial Statistics Tools > Mapping Clusters and open the Optimized Hotspot Analysis tool. This tool allows for quick hotspot analysis using minimal input parameters and sets/calculates default parameters for those you have no control over.  What is Getis Ord Gi * statistic? The

Storing shapefile in PostgreSQL database as a table using PHP?

Can we store file in PostgreSQL database? BLOB is a Binary large object (BLOB) is a data type that can store any binary data. To Store Blob data in a Postgres database Table, we will use psycopg2. The table for storing BLOB data in PostgreSQL is called a Large Object table and the data type

Select features from attribute table and then create a new field with the selected attribute data

How do I add a new field to an attribute table? i. In ArcMap, right-click the shapefile layer in the table of contents and click Open Attribute Table. ii. Click the Options button and click Add Field. How do I create a new field in an attribute table in Arcgis? No other users or applications

Difference between Merge Raster Layers and Build Virtual Raster in QGis?

What is a virtual raster QGIS? A virtual raster (VRT) is a special type of file that references one or more existing raster datasets and combines them into a single virtual layer.  Can you merge raster layers in QGIS? QGIS uses the the GDAL merge tool, which is a very fast and efficient tool, to

Creating DEM after converting MapInfo tab files to ArcGIS Desktop?

How do I convert MapInfo to ArcGIS? ArcGIS will not read MapInfo files directly; instead, the user must create a MapInfo Interchange Format (MIF) file in MapInfo (using Table > Export) which can then be imported into ArcGIS. MIF is a file format which enables both graphical and tabular data from MapInfo to be imported

Remove unwanted multipolgon parts

How do you Delete part of a multipart polygon in ArcMap? on the Manage Features window. Select a multipart polygon or line feature. on the Production Editing toolbar. Right-click a node on the part of the feature you want to delete and click Delete Feature Part. How to remove overlapping areas of a polygon without

CSV file not joining to Shapefile using QGIS?

How do I link a CSV file to a shapefile in QGIS? Steps to join: Open csv via the open vector icon. Open properties tab on the layer you want to join onto (your map) Click the Join tab and press the + button. Select the csv layer and the two columns that you want

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