on January 25, 2023
Calculating area with formula gives zero in the attribute table in QGIS
Geographic Information SystemsHow do I replace null with 0 in QGIS? You can do this directly in the field calculator: Open the field calculator. Check the “Update Existing Field” box. Select the field you want to work on. Enter the following expression in the expression box: if(“fieldname” is null, 0, “fieldname”) , replacing fieldname with the actual
on January 25, 2023
Intersection of points for overlapping polygons
Geographic Information SystemsHow do you fix overlapping polygons? Removing overlaps from existing polygons Select the polygon feature whose border you want to maintain. The other polygon will be clipped back to match it. Click the Editor menu and click Clip. Set the buffer distance to 0 and choose to discard the area that intersects. Click OK. How
on January 25, 2023
Unsupervised classification in Google Earth Engine
Geographic Information SystemsHow do you use unsupervised classification in Google Earth Engine? Unsupervised Classification (clustering) Assemble features with numeric properties in which to find clusters. Instantiate a clusterer. Set its parameters if necessary. Train the clusterer using the training data. Apply the clusterer to an image or feature collection. Label the clusters. Can unsupervised learning be used
on January 25, 2023
Editing multiple layers using QGIS?
Geographic Information SystemsHow do I edit multiple layers in QGIS? Select the layer in the Layers panel and click Layer | Toggle Editing. Alternatively you can right click on a layer in the Layers panel and choose Toggle Editing from the context menu. Multiple layers can be edited at a time. The layer currently being edited is
on January 25, 2023
Visibility of multiple points from one other point?
Geographic Information SystemsWhat is a line-of-sight analysis? Line-of-sight (LOS), also called “viewshed analysis,” can be used to determine what can be seen from a particular location in the landscape. Conversely, the same analysis also determines from where within the surroundings that location can be seen. What is Viewshed analysis used for? A viewshed identifies the cells in
on January 25, 2023
Accessing GeoServer on own domain (Windows OS)
Geographic Information SystemsHow do I connect to Geoserver? In a web browser, navigate to http://localhost:8080/geoserver . Log into GeoServer as described in the Logging In section. Navigate to Data ‣ Workspaces. Workspaces page. Click the Add new workspace button. You will be prompted to enter a workspace Name and Namespace URI. Click the Submit button. How to
on January 25, 2023
Add location search to openlayers map
Geographic Information SystemsCan I use Google Maps with OpenLayers? Unlike Bing Google does not allow its map tiles to be used directly in Openlayers, and you can’t use OpenLayers code in the Google maps API so you would need to rewrite much of it. However, it is possible to use javascript to place an Openlayers map and
on January 25, 2023
Create GeoTIFF images from TIFF image using the coordinates of the four corners
Geographic Information SystemsDo TIFF files have coordinates? In the TIFF/GeoTIFF framework, there are essentially three different spaces upon which coordinate systems may be defined. The spaces are: 1) The raster space (Image space) R, used to reference the pixel values in an image, 2) The Device space D, and 3) The Model space, M, used to reference
on January 25, 2023
How to convert double bearing into x and y coordinate
Geographic Information SystemsHow do you convert bearings to coordinates? Quote from video: The departure is calculated by L sine theta and the latitude is calculated by L cos theta. So if you know the coordinate of point a then you can get the coordinate of easting/northing. How do you convert angles into X and Y coordinates? Quote
on January 25, 2023
In arcmap how to modify time value in editor tracking fields
Geographic Information SystemsHow do you change a value field in ArcGIS? Note: Click the Editor menu on the Editor toolbar and click Start Editing. Right-click the table or layer in the table of contents and choose Open Attribute Table. Click the cell containing the attribute value you want to change. Tip: Type the values and press ENTER.