Read layered maps the way GIS does: overlay and find the pattern

Grade 9 Social Studies Worksheet

Circle the best answer.

1. Read this first

   Use this

   Card C. Egypt: water, farms and people, drawn as see-through layers on one base map. Egypt's land area is about 1 million km². Layer 1 (water): the Nile flows north through Egypt to its delta on the Mediterranean Sea. Layer 2 (farmland): cultivated land, about 35,000 km², or about 3.5% of Egypt's land, lies along the Nile and in the delta; the rest is desert. Layer 3 (people): almost all of Egypt's people live in the Nile Valley and Delta, which cover only about 5% of the country. Key: blue = river; green = cultivated land; dark shading = where most people live; tan = desert. Note: nine governorates of Lower Egypt lie in the delta, and ten of Upper Egypt line the Nile from Cairo south to Aswan.

2. 1.

   Jun overlays the farmland layer on the Nile Valley and Delta (about 5% of Egypt's land). About what share of the valley and delta is cultivated?

   • About 35%, because the 35,000 km² of farmland is taken out of 100,000 km² of valley and delta
   • About 5%, because the valley and delta cover 5% of the country and so the farmland fills the same share
   • About 3.5%, the share of Egypt's land that is cultivated, since the overlay keeps the same share inside the valley
   • About 70%: the valley and delta cover about 50,000 km², and 35,000 km² of it is cultivated
3. 2.

   Pia says: "The Nile makes almost all of Egypt's people live along it." What do the layers support?

   • Nothing follows, because a map of three layers cannot show anything about where people live
   • The note is wrong, because just 3.5% of Egypt is farmland and so most people cannot depend on the river
   • The note is right, since the overlay shows the people layer sitting on top of the river layer, which shows the river caused it
   • The people, farmland and river layers line up along the Nile, but the overlay does not show why people settled there

4. Use this

   Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

5. 3.

   Zee runs a query on Card D: villages within 1 km of a canal AND on cultivated land. How many villages does it keep?

   • Six villages, the ones that meet both conditions, as the overlay result states
   • Eleven villages, the ones that meet at least one of the two conditions, 9 + 8 - 6
   • Nine villages, the ones within 1 km of a canal, since AND takes just the first layer
   • Seventeen villages, the 9 near canals plus the 8 on farmland, counted separately
6. 4.

   Kira runs a second query on Card D: within 1 km of a canal OR on cultivated land. How many villages does it keep, and why not 17?

   • Twelve villages, because OR with two layers keeps the whole district
   • Six villages, because OR keeps just the villages that meet both conditions
   • Seventeen villages, because OR adds the villages in each group and the two groups are separate
   • Eleven villages: 9 + 8 = 17 counts the six in both groups twice, so subtract them once
7. 5.

   Ren runs: on cultivated land AND NOT within 1 km of a canal. How many villages does it keep?

   • Eight villages, because NOT just removes the villages near a canal that are not farmland
   • Two villages: 8 on cultivated land, minus the 6 that are also within 1 km of a canal
   • One village, the one that meets neither condition, since NOT picks out the village left out
   • Three villages, the ones within 1 km of a canal but not on cultivated land, since NOT removes farmland
8. 6.

   Esme compares two shares on Card D: villages on farmland that are near a canal, and villages near a canal that are on farmland. Which is right?

   • Both are 6 of 12, which is 50%, since the district has 12 villages and 6 meet both conditions
   • Both are 75%, because the overlap of 6 is the same in each and so the share must be the same
   • 75% of farmland villages are near a canal (6 of 8); about 67% of canal villages are on farmland (6 of 9)
   • About 67% of the farmland villages are near a canal, and 75% of the canal villages are on farmland
9. 7.

   Noah says: "Canals cause farmland, because 6 of the 9 canal villages are on cultivated land." What does Card D support?

   • Nothing can be said, because 12 villages are too few for any link between canals and farmland
   • A link, since 6 of 9 canal villages are on farmland, yet 2 farmland villages have no canal near
   • The claim is wrong, because 3 of the 9 canal villages are not on farmland and so canals do not matter
   • The claim is right, because most canal villages are on farmland and so the canals made the farmland

10. Use this

    Card C. Egypt: water, farms and people, drawn as see-through layers on one base map. Egypt's land area is about 1 million km². Layer 1 (water): the Nile flows north through Egypt to its delta on the Mediterranean Sea. Layer 2 (farmland): cultivated land, about 35,000 km², or about 3.5% of Egypt's land, lies along the Nile and in the delta; the rest is desert. Layer 3 (people): almost all of Egypt's people live in the Nile Valley and Delta, which cover only about 5% of the country. Key: blue = river; green = cultivated land; dark shading = where most people live; tan = desert. Note: nine governorates of Lower Egypt lie in the delta, and ten of Upper Egypt line the Nile from Cairo south to Aswan. Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

11. 8.

    Ari compares Card D's delta villages with Card C's Egypt. In which place is the overlap of farms and canals better supported by the data?

    • In Egypt, where the Nile layer overlaps the farmland layer along the whole river, so it has the stronger evidence
    • In the delta district, where Card D counts 6 of 12 villages in both layers; Card C has no canal layer
    • In neither, because one is made up and the other has no canals, so neither can be used for this overlap
    • In both equally, because each shows a water layer next to a farmland layer, so both give equal support
12. 9.

    Luz says the delta district is a good sample for Egypt's delta. What does Card C say that Card D cannot?

    • Card C gives real land areas for the whole country, while Card D is a made-up sample of 12 villages
    • Card C shows the delta has more villages than the valley, so Card D should have more villages near the sea
    • Card C includes the canals in the delta, so it can check Card D's canal layer
    • Card D is a random sample of Egypt's delta villages, so its 6 of 12 can be used for the whole delta

13. Use this

    Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

14. 10.

    Tala asks how many of Card D's 12 villages meet neither condition (near a canal, on cultivated land). What is the count?

    • Six villages: the villages that meet both conditions, since NOT removes them from the district
    • Zero villages: 9 near a canal plus 8 on farmland is 17, which is more than the 12 villages
    • One village: 12 minus the 11 that are near a canal or on cultivated land
    • Three villages: 12 minus the 9 near a canal, since the rest are not near water and so are left out