UsTract2010 Database

The UsTractMap class stores the map data and exposes a query method to find the tract and related metadata at a given latitude and longitude. Because each UsTractMap instance is quite large, we recommend instantiating a single static instance in your project. The methods that you will need to use are as follows.

class UsTractMap {

static UsTractMap create(InputStream dataFileStream)

UsTractResult findResult(float latDeg, float lonDeg)

// Additional methods exist in this class; for complete documentation, please see the Full Java Docs

}

The UsTractResult class embodies the result of a query on a UsTractMap instance. All of the results listed in the Returned Values Section may be accessed using an accessor whose method name consists of "get" followed by the Key parameter from the Returned Values tables. Those tables also specify the type of the returned value. For example, here are several important accessors:

class UsTractResult {

String getTractName()

float GetCensusTotalPopulation()

float GetCensusAgeMedianAge()

float GetAcsHouseholdIncomeMedian()

// Additional methods exist in this class; for complete documentation, please see the Full Java Docs

}

The CensusField and AcsField enums lists the fields taken from the 2010 US Census and 2006-2010 American Community Survey that are reported for each tract. These may be used with the UsTractResult to access these data if, for whatever reason, the more traditional accessors are not suitable to the application at hand. For example, some applications might result in having a list of desired fields, which could be represented as a list of CensusField or AcsField members, and accessed in a for loop.

The following methods on the UsTractResult class work with these enums:

class UsTractResult {

String getAcsField(AcsField field)

float getAcsFieldAsFloat(AcsField field)

String getCensusField(CensusField field)

float getCensusFieldAsFloat(CensusField field)

// Additional methods exist in this class; for complete documentation, please see the Full Java Docs

}

Please note that if you are just trying to access a couple of fields that are known at compile time, it is probably much easier to use the direct accessors documented here.

The following is a complete example program demonstrating the use of the Ask Geo UsTract2010 Java Library.

import com.askgeo.flt.base.AcsField;
import com.askgeo.flt.us.census2010.low.UsTractMap;
import com.askgeo.flt.us.census2010.low.UsTractResult;

import java.io.FileInputStream;

public class UsCensusExample {
    static float[][] examplePoints = {{37f, -122f}, {42f, -89f}};
    static String license = "INSERT YOUR LICENSE STRING HERE";
    static String dataFilePath = "askgeo-us-state-2010-low-1.1.0.dat";

    public static void main(String[] args) {
        try {
            UsTractMap map = UsTractMap.create(new FileInputStream(dataFilePath));
            map.authorize(license);
            for (float[] point : examplePoints) {
                UsTractResult result = map.findResult(point[0], point[1]);
                String name = result.getTractName();
                float population = result.getCensusTotalPopulation();
                float medianAge = result.getCensusAgeMedianAge();
                float medianIncome = result.getAcsFieldAsFloat(AcsField.AcsHouseholdIncomeMedian);
                System.out.println(" Latitude: " + point[0] +
                        ", Longitude: " + point[1] +
                        ", Name: " + name +
                        ", Population: " + population +
                        ", Median Age: " + medianAge +
                        ", Median Income: " + medianIncome);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

The UsTractMap class stores the map data and exposes a query method to find the tract and related metadata at a given latitude and longitude. Because each UsTractMap instance is quite large, we recommend instantiating a single static instance in your project. The methods that you will need to use are as follows.

class UsTractMap {

static UsTractMap Create(Stream dataFileStream)

UsTractResult FindResult(float latDeg, float lonDeg)

// Additional methods exist in this class; for complete documentation, please see the Full .NET Docs

}

The UsTractResult class embodies the result of a query on a UsTractMap instance. All of the results listed in the Returned Values Section may be accessed using an accessor whose method name consists of "Get" followed by the Key parameter from the Returned Values tables. Those tables also specify the type of the returned value. For example, here are several important accessors:

class UsTractResult {

String GetTractName()

float GetCensusTotalPopulation()

float GetCensusAgeMedianAge()

float GetAcsHouseholdIncomeMedian()

// Additional methods exist in this class; for complete documentation, please see the Full .NET Docs

}

The CensusField and AcsField classes lists (as static public members) the fields taken from the 2010 US Census and 2006-2010 American Community Survey that are reported for each tract. These may be used with the UsTractResult to access these data if, for whatever reason, the more traditional accessors are not suitable to the application at hand. For example, some applications might result in having a list of desired fields, which could be represented as a list of CensusField or AcsField members, and accessed in a for loop.

The following methods on the UsTractResult class work with the static public members of these classes:

class UsTractResult {

String GetAcsField(AcsField field)

float GetAcsFieldAsFloat(AcsField field)

String GetCensusField(CensusField field)

float GetCensusFieldAsFloat(CensusField field)

// Additional methods exist in this class; for complete documentation, please see the Full .NET Docs

}

Please note that if you are just trying to access a couple of fields that are known at compile time, it is probably much easier to use the direct accessors documented here.

The following is a complete example program demonstrating the use of the Ask Geo UsTract2010 .NET Library.

using System;
using System.IO;
using AskGeo.Flt;
using AskGeo.Base;

class UsCensus {
    static void Main(string[] args) {
        float[,] examplePoints = { { 37f, -122f }, { 42f, -89f } };
        String license = "INSERT YOUR LICENSE STRING HERE";
        String dataFilePath = @"askgeo-us-state-2010-low-1.1.0.dat";

        UsTractLowMap map = UsTractLowMap.Create(new FileStream(dataFilePath, FileMode.Open));
        map.Authorize(license);

        for (int i = 0; i < examplePoints.GetLength(0); i++) {
            UsTractLowResult result = map.FindResult(examplePoints[i, 0], examplePoints[i, 1]);
            String name = result.GetTractName();
            float population = result.GetCensusTotalPopulation();
            float medianAge = result.GetCensusAgeMedianAge();
            float medianIncome = result.GetAcsFieldAsFloat(AcsField.AcsHouseholdIncomeMedian);
            Console.WriteLine(" Latitude: " + examplePoints[i, 0] +
                    ", Longitude: " + examplePoints[i, 1] +
                    ", Name: " + name +
                    ", Population: " + population +
                    ", Median Age: " + medianAge +
                    ", Median Income: " + medianIncome);

        }
    }
}