on February 7, 2023
Creating an sf object from the maps package
Geographic Information SystemsHow do you create an SF object? Quote from video: In practice sf objects are usually created by reading in a shapefile or something like that however particularly for point observations. What package is SF in R? The sf package represents simple features as native R objects, using simple data structures (S3 classes, lists, matrices,
on February 7, 2023
Add Geometry Attributes tool failing on line feature class and giving no error code using ArcMap
Geographic Information SystemsHow do I fix invalid geometry in ArcGIS? Start ArcMap. On the main menu, click Customize > Toolbars > Data Reviewer. Click the Select Data Check drop-down arrow on the Data Reviewer toolbar, click the plus sign (+) next to Default Checks, then click Invalid Geometry Check. Why can’t I add a field to attribute
on February 7, 2023
Creation of polygon in the gap between two existing polygons
Geographic Information SystemsHow do I fill gaps between two polygons in Arcgis? Select the polygons that have holes you want to fill. on the Production Editing Advanced toolbar. Press the Ctrl key and click inside any of the selected polygons. The Fill Hole message appears and notifies you that all holes in the selected features will be
on February 7, 2023
Why are my polygon features area being calculated as zero?
Geographic Information SystemsHow do you find the area of a polygon? The formula to calculate the area of a regular polygon is, Area = (number of sides × length of one side × apothem)/2, where the value of apothem can be calculated using the formula, Apothem = [(length of one side)/{2 ×(tan(180/number of sides))}]. How do you
on February 7, 2023
Removing parts of raster layer with QGIS (equivalent of vector difference tool)?
Geographic Information SystemsHow do I trim a raster image in QGIS? Clipper Tool Verify the raster you want clipped is the Input file. Click “Select…” next to the Output file, find your working folder, and name the output raster. Click the radio button next to Mask layer and use the drop-down arrow to select the layer you
on February 7, 2023
Using QGIS SpatiaLite/Geopackage databases on shared network drives
Geographic Information SystemsCan you open a GeoPackage in QGIS? You are now ready to add any layer from this GeoPackage to QGIS. Click on the Connect button. In the central part of the window you should now see the list of all the layers contained in the GeoPackage file. Select the roads layer and click on the
on February 7, 2023
Comparing two spatial datasets statistically
Geographic Information SystemsHow do you compare spatial distributions? To analyze the spatial distribution of attribute values (not features itself, but certain attribute values), you can divide (weigh) the values by distance to neighbors and create a frequency distribution. You can then compare that against a uniform or random distribution. What is the statistical test for spatial distribution?
on February 7, 2023
Check data from ArcPad
Geographic Information SystemsWhere is Arc map data? The following steps describe how you can view your data in ArcMap: Start ArcMap, open the Catalog window, and connect to your database. Click the table in the Catalog tree to select it. To view the data, drag the table from the Catalog window to the table of contents or
on February 7, 2023
Is QGIS multi-threaded?
Geographic Information SystemsDoes QGIS use multiple cores? QGIS uses by default only one CPU core for rendering, but you can change this. Multi-threaded rendering should speed up your performance significantly! How do I enable multithreading in QGIS? To enable it, open the Options dialog, select the Rendering tab and check the Render layers in parallel using many
on February 7, 2023
What is a good world reference atlas with information for each country?
Geographic Information SystemsWhich atlas is best for world? No atlas is more accurate than Oxford’s Atlas of the World. Combined with stunning photography, detailed charts and graphs, and crisp cartography of urban and natural locations, this volume is one of the best world atlas choices on the market. What reference book would you use to find a