Union: Merge the input feature classes into the new feature class. Graphics: Union can only merge feature classes of type polygon. When two feature classes are merged, the intersecting parts are processed to form multipart features individually, with options to allow gaps gaps or gaps to be allowed.
If you choose not to allow a gap, the merged gap of the two feature classes will generate features. All the attribute table fields of the two feature classes are placed in the order of the attribute tables of the output feature class, including the FID. Union does not do field mapping. Graphics: Merge can merge feature classes and tables, such as points, lines, and polygons, but must be of the same type.
Merge does not process features, it simply places features in a feature class, so the output feature classes may have overlapping or gaps. The data table includes only the salamander OR the frog, but not both.
I made this comparison because I thought there might be a way to append fields from the union data tables; while I can think of a way to do this with the field calculator, I would like to understand the logic prior to advancing in this direction.
I was also surprised that polygon union SAGA did not give the same result as union QGIS vector overlay , which makes me concerned and wonder about the steps that I followed to build the initial layers. This creates another type of output that looks more like the merge function in the QGIS. Is there a single illustrative resource that could help me to understand the difference in logic as it applies to the QGIS functions union, merge, join, intersection as this relates to the data tables as described in this example; same goes for r-stats sf package?
I note that there is the plugin called "Append Features to Layer", but I want to clearly understand the logic to manage my data appropriately to bring this information together logically and with the correct final answer. I don't understand everything you're trying to achieve, but I think this will help with some of it:. When you have a result with the amphibian field data in multiple fields, use the Field Calculator to concatenate the data from those two fields.
Note the two different concatenation methods. The difference is in how they handle NULL input. You can further refine this expression in many ways, depending on what the inputs are likely to be. Note: You won't be able to create a new field called "Amphibian" if you already have a field with that name. Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 2 years, 5 months ago. Active 2 years, 5 months ago. The table fields are all placed in the attribute table of the output feature class in sequence, including fid. Fields with the same name except for fid after the field name.
Add numbers to show the difference fid plus the name of the feature class. The order is all placed in the attribute table of the output feature class.
In the attribute table of the class, add the feature class name after fid to show the difference. Union does not do field mapping. Graphics: merge can merge feature classes and tables such as points, lines, and polygons, but they must be of the same type. Attribute table: When merge processing the attribute table, the fields with the same name will be combined into one, and the fields with different names will be in the original name and order.
All added to the output feature class attribute table, the original fid will be discarded. Merge can perform field mapping. And raster catalogs. Also, it is one of only two classified as a level 7 event the maximum classification. Surrounding vegetation absorbed radioactive isotopes and died within a week of the blast. As a result of the deadly toxins released into the atmosphere, the safety crew declared a square kilometer buffer around the nuclear power plant.
There are an estimated to 93, deaths across Europe. And the exclusion zone is still in effect. Since the blast, satellites like SPOT have been monitoring the Chernobyl exclusion zone because of its restrictions.
The clip tool is an overlay function that cuts out an input layer with the extent of a defined feature boundary. The result of this tool is a new clipped output layer. If you can picture a cookie cutter, this is like using the clip tool. And carving out vectors and rasters is one of the most common operations in GIS. To clip data, you need points, lines, or polygons as input and a polygon as the clipping extent.
The preserved data is the result of a clip. You can even find the Sunshine State on their license plate. But how much sunshine does Florida really receive? It turns out that global horizontal irradiance GHI is a good measure of incoming solar radiation. So if you wanted to install a solar panel, GHI is the recommended data set. If you clip GHI to the Florida state boundary, you can really find how much sunshine Florida really gets.
The merge tool combines data sets that are the same data type points, lines, or polygons. When you run the merge tool, the resulting data will be merged into one. Similar to the clip tool, we use the merge tool regularly. For merging, data sets have to be the same type. For example, if two grocery store giants like Ahold NV and Delhaize Group want to combine their 6, stores, we can use the merge tool. In this case, we have two existing data sets from both companies.
The merger between the two grocery stores into one company — Ahold Delhaize — means all grocery stores will be combined into a single data set.
When you combine grocery stores points from both companies, they all end up in a final data set. The dissolve tool unifies boundaries based on common attribute values. In other words, dissolve merges neighboring boundaries if the neighbors have the same attributes. For example, if you want to remove the borders of countries to form a continent, the dissolve tool is the tool to use.
But you would need an attribute for each country and the continent it belongs to. What do Germany , Yemen , Tanzania , and Vietnam all share in common?
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