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How to select by location with multiple source layers?

How to select by location with multiple source layers?


I would like to script the selection of the square that contains both the orange and green points, but not the squares with any other combination of points including white points. I am very familiar with python, but I do not know if the process of selecting a target feature with two sources layers is even possible. I cannot seem to figure out the process even within ArcMap's GUI. This seems like it should be easy. Any ideas?

Pseudo code: If square contains both orange and green points but only those points > select


You can do it in the GUI, just not all at once. Multiple selections are required using a 'current selected set' that gets modified. One option would be:

  1. Select squares that intersect green.
  2. Per Michael's comment, change method to 'from current' rather than 'create new', and select squares that intersect orange. You should now have all squares containing both green and orange and none that contain only one or the other (but some may contain white as well).
  3. Again change the method, this time to 'remove from current', and do those that intersect white. You should be left with squares that only contain green and orange, and nothing else.

Related question with some help document links, which would address a case if your points were all one layer (requiring both a location and attribute selection): Select by Attribute within a specific area (using Select by Location?)


GIS Analysis Functions

GIS analysis functions use the spatial and non-spatial attribute data to answer questions about real-world. It is the spatial analysis functions that distinguishes GIS from other information systems.

When use GIS to address real-world problems, you'll come up against the question that which analysis function you want to use and to solve the problems. In this case, you should be aware that wisely using functions will lead to high quality of the information produced from GIS and individual analysis functions must be used in the context of a complete analysis strategy. (Stan Aronoff, 1989)


Checking for a Coordinate System

  1. Right click on the title of your Map Layer in the Table of Contents of ArcMap. Choose Properties at the bottom of the pop up menu.
  2. Click on the Source tab.
  3. In the Data Source section, there should be a label that says Geographic Coordinate System or Projected Coordinate System. This tells you which Coordinate System this map layer uses.
  4. Check all of your other Map Layers to make sure that they are using the same Coordinate System. If not, use the directions below to change the Coordinate Systems to match one another.

Create a Map chart with Data Types

Map charts have gotten even easier with geography data types. Simply input a list of geographic values, such as country, state, county, city, postal code, and so on, then select your list and go to the Data tab > Data Types > Geography. Excel will automatically convert your data to a geography data type, and will include properties relevant to that data that you can display in a map chart. In the following example, we've converted a list of countries to geography data types, then selected the Tax revenue (%) field from the Add Column control to use in our map.

Now it's time to create a map chart, so select any cell within the data range, then go to the Insert tab > Charts > Maps > Filled Map.

If the preview looks good, then press OK. Depending on your data, Excel will insert either a value or category map.

Tip: If your data is set up as an Excel table, and then you add a country to the list, Excel will automatically update it as a geography data type and update the linked map chart. Similarly, if you remove a country, then Excel will also remove it from the chart.


Relating tables

Unlike joining tables, relating tables simply defines a relationship between two tables. The associated data isn't appended to the layer's attribute table like it is with a join. Instead, you can access the related data when you work with the layer's attributes.

For example, if you select a building, you can find all the tenants that occupy that building. Similarly, if you select a tenant, you can find what building it resides in (or several buildings, in the case of a chain of stores in multiple shopping centers—a many-to-many relationship). However, if you performed a join on such data, ArcMap will only find the first tenant belonging to each building, ignoring additional tenants.

Relates defined in ArcMap are essentially the same as simple relationship classes defined in a geodatabase, except that they are saved with the map instead of in a geodatabase.

If your data is stored in a geodatabase and has relationship classes defined, you can use these directly without having to establish a relate in ArcMap. The relationship classes will automatically be available when you add a layer that participates in a relationship class to the map. Note that the many-to-many relationship is defined differently when your data is stored in a geodatabase. In general, if you have relationship classes defined in your geodatabase, you should use these instead of creating new ones in ArcMap.


Create a dual-axis map from custom latitude and longitude fields

If your data source contains custom latitude and longitude fields, you can use them instead of the Tableau Latitude (generated) and Longitude (generated) fields to create a dual-axis map. Follow the steps below to learn how.

Open Tableau and connect to a data source with custom latitude and longitude values.

Navigate to a new worksheet.

In the Data pane, right-click the custom latitude field and select Geographic Role > Latitude .

Note that the Latitude geographic role may already be assigned to the field.

In the Data pane, right-click the custom longitude field and select Geographic Role > Longitude .

Note that the Longitude geographic role may already be assigned to the field.

From the Data pane, drag the custom latitude field to the Rows shelf.

From the Data pane, drag the custom longitude field to the Columns shelf.

From the Data pane, under Dimensions, drag a geographic field to Detail on the Marks card.

In this example, the geographic field, Country (Name), is used.

On the Marks card, click the Mark Type drop-down and select Map .

The map updates to a filled map.

On the Rows shelf, Ctrl-click (Command-click on a Mac) and drag the custom latitude field to the right. This copies the field.

A second, identical map is created and the Marks card updates to include three tabs. The middle tab is for the top map, and the bottom tab is for the bottom map.

On the Marks card, click the bottom tab and remove the geographic field by dragging it off.

From the Data pane, drag a new geographic field to Detail on the Marks card.

In this example, Airport (City) is used.

On the Marks card, click Color and select a color for the marks. In this example, the color orange is used.

On the Rows shelf, right-click the custom latitude field on the right and select Dual Axis .

The two maps are now combined.


5. Map Overlay Concept

Environmental scientists and engineers consider many geological, climatological, hydrological, and surface and subsurface land use criteria to determine whether a plot of land is suitable or unsuitable for a LLRW facility. Each criterion can be represented with geographic data, and visualized as a thematic map. In theory, the site selection problem is as simple as compiling onto a single map all the disqualified areas on the individual maps, and then choosing among whatever qualified locations remain. In practice, of course, it is not so simple.

There is nothing new about superimposing multiple thematic maps to reveal optimal locations. One of the earliest and most eloquent descriptions of the process was written by Ian McHarg, a landscape architect and planner, in his influential book Design With Nature. In a passage describing the process he and his colleagues used to determine the least destructive route for a new roadway, McHarg (1971) wrote:

As you probably know, this process has become known as map overlay. Storing digital data in multiple "layers" is not unique to GIS, of course computer-aided design (CAD) packages and even spreadsheets also support layering. What's unique about GIS, and important about map overlay, is its ability to generate a new data layer as a product of existing layers. In the example illustrated below, for example, analysts at Penn State's Environmental Resources Research Institute estimated the agricultural pollution potential of every major watershed in the state by overlaying watershed boundaries, the slope of the terrain (calculated from USGS DEMs), soil types (from U.S. Soil Conservation Service data), land use patterns (from the USGS LULC data), and animal loading (livestock wastes estimated from the U.S. Census Bureau's Census of Agriculture).

As illustrated below, map overlay can be implemented in either vector or raster systems. In the vector case, often referred to as polygon overlay, the intersection of two or more data layers produces new features (polygons). Attributes (symbolized as colors in the illustration) of intersecting polygons are combined. The raster implementation (known as grid overlay) combines attributes within grid cells that align exactly. Misaligned grids must be resampled to common formats.


Manage data

These tools are used for both the day-to-day management of geographic data and for combining data prior to analysis.

This tool extracts data that you select for a specified area of interest. Layers that you select are added to a .zip file or layer package.

This tool merges areas that overlap or share a common boundary to form a single area.

You can control which boundaries are merged by specifying a field. For example, if you have a layer of counties and each county has a State_Name attribute, you can dissolve boundaries using the State_Name attribute. Adjacent counties are merged if they have the same State_Name value. The result is a layer of state boundaries.

This tool creates bins of a specified shape and size for the study area.

Bins can be square, hexagonal, transverse hexagonal, triangular, or diamond shaped.

This tool copies features from two layers into a new single layer. The layers to be merged must all contain the same feature types (points, lines, or areas). You can control how the fields from the input layers are joined and copied.

  • Merge a layer of public schools and a layer of private schools into a single layer showing all schools.
  • Merge two layers which each contain parcel information for contiguous townships into a single layer, keeping only the fields that have the same name and data type for the two input layers.

This tool combines two or more layers into a single layer. You can think of overlay as peering through a stack of maps and creating a single map containing all the information found in the stack. Overlay is much more than a merging of line work all the attributes of the features taking part in the overlay are carried through to the final product. Overlay is used to answer one of the most basic questions of geography: What is on top of what?

  • What parcels are within the 100-year floodplain? (Within is just another way of saying on top of.)
  • What roads are within what counties?
  • What land use is on top of what soil type?
  • What wells are within abandoned military bases?

How to select by location with multiple source layers? - Geographic Information Systems

A global positioning system (GPS) is a network of satellites and receiving devices used to determine the location of something on Earth. Some GPS receivers are so accurate they can establish their location within 1 centimeter.

Geography, Geographic Information Systems (GIS), Physical Geography

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The global positioning system (GPS) is a network of satellites and receiving devices used to determine the location of something on Earth. Some GPS receivers are so accurate they can establish their location within 1 centimeter (0.4 inches). GPS receivers provide location in latitude, longitude, and altitude. They also provide the accurate time.

GPS includes 24 satellites that circle Earth in precise orbits. Each satellite makes a full orbit of Earth every 12 hours. These satellites are constantly sending out radio signals.

GPS receivers are programmed to receive information about where each satellite is at any given moment. A GPS receiver determines its own location by measuring the time it takes for a signal to arrive at its location from at least four satellites. Because radio waves travel at a constant speed, the receiver can use the time measurements to calculate its distance from each satellite.

Using multiple satellites makes the GPS data more accurate. If a GPS receiver calculates its distance from only one satellite, it could be that exact distance from the satellite in any direction. Think of the satellite as a flashlight. When you shine it on the ground, you get a circle of light. With one satellite, the GPS receiver could be anywhere in that circle of light. With two more satellites, there are two more circles. These three circles intersect, or cross, in only one place. That is the location of the GPS receiver. This method of determining location is called trilateration.

Aircraft, ships, submarines, trains, and the space shuttle all use GPS to navigate. Many people use receivers when driving cars. The GPS receiver plots the car's constantly-changing location on an electronic map. The map provides directions to the person's destination. Both the location and the vehicle are plotted using satellite data. Some hikers use GPS to help them find their way, especially when they are not on marked trails.

Sometimes there are obstacles to getting a clear GPS signal. Gravity can pull the GPS satellites slightly out of orbit. Parts of Earth's atmosphere sometimes distort the satellite radio signals. Trees, buildings, and other structures can also block the radio waves. GPS control and monitoring stations around the world track the satellites and constantly monitor their signals. They then calculate corrections that are broadcast to GPS receivers. These corrections make GPS much more accurate.

The original GPS system began as a project of the U.S. military. The first experimental satellite was launched in 1978. By 1994, a full 24 GPS satellites were orbiting Earth. At first, GPS available for civilian, or nonmilitary, use was not very accurate. It would only locate a GPS receiver within about 300 meters (1,000 feet). Today, an accurate signal is free and available to anyone with a GPS receiver.

GPS is American. Russia has its own version of a GPS system, called GLONASS (Global Orbiting Navigation Satellite System). China and the European Union are currently creating systems of their own.

Photograph by Scott S. Warren

Tracking
GPS technology is used to track animals as they migrate. Animals, from humpback whales to arctic terns to grizzly bears, are fitted with GPS receivers. These receivers let researchers know where that animal is as it moves. Biologists can track animals as they migrate to another habitat for a season, move in search of food or shelter, or are forced out of their ecosystem by human activity such as construction.

Early Warning
Scientists are using GPS to quickly determine the size of earthquakes. First, scientists plant GPS receivers in the ground. By measuring how far these GPS receivers move, scientists can sometimes measure the strength of an earthquake in as little as 15 minutes.

Knowing the size of an earthquake is central to predicting whether it can produce dangerous ocean waves known as a tsunamis. By the time a tsunami reaches land, it can be a huge, destructive wall of water. Early warning is crucial in saving lives because tsunami waves move faster than people can run.


Relates can help you discover specific information in your data. For example, if you select a building, you can find all the tenants that occupy that building. Similarly, if you select a tenant, you can find what building they reside in (or several buildings, in the case of a chain of stores in multiple shopping centers—a many-to-many relationship). A relate or relationship class is recommended when using data where a one-to-many or many-to-many relationship exists.

Unlike joining tables, relating tables defines a relationship between two tables. The associated data isn't appended to the layer's attribute table like it is with a join. Instead, you can access the related data through selected features or records in your layer or table. You can create a relate using the Add Relate geoprocessing tool.

Relates that are added to a layer or table in a map are essentially the same as simple relationship classes defined in a geodatabase, except that they are saved with the map instead of in a geodatabase. A relationship class stores information about associations among features and records in a geodatabase and can help ensure your data's integrity. To create a relationship class, use the Create Relationship Class tool or right-click the geodatabase in the Catalog pane, point to New , and click Relationship .

If a feature class in a geodatabase already participates in a relationship class, you don't need to create a relate for the tables. It is already available for use and listed in the Related Data menu that you can use to view related data. Note that the many-to-many relationship is defined differently when your data is stored in a geodatabase.


Watch the video: QGIS - Select By Expression - Select By Attribute